2D MXene(Ti_(3)CNT_(x))has been considered as the most promising electrode material for flexible supercapacitors owing to its metallic conductivity,ultra-high capacitance,and excellent flexibility.However,it suffers f...2D MXene(Ti_(3)CNT_(x))has been considered as the most promising electrode material for flexible supercapacitors owing to its metallic conductivity,ultra-high capacitance,and excellent flexibility.However,it suffers from a severe restacking problem during the electrode fabrication process,limiting the ion transport kinetics and the accessibility of ions in the electrodes,especially in the direction normal to the electrode surface.Herein,we report a NH_(3)-induced in situ etching strategy to fabricate 3D-interconnected porous MXene/carbon dots(p-MC)films for high-performance flexible supercapacitor.The pre-intercalated carbon dots(CDs)first prevent the restacking of MXene to expose more inner electrochemical active sites.The partially decomposed CDs generate NH_(3)for in situ etching of MXene nanosheets toward 3D-interconnected p-MC films.Benefiting from the structural merits and the 3D-interconnected ionic transmission channels,p-MC film electrodes achieve excellent gravimetric capacitance(688.9 F g^(-1)at 2 A g^(-1))and superior rate capability.Moreover,the optimized p-MC electrode is assembled into an asymmetric solid-state flexible supercapacitor with high energy density and superior cycling stability,demonstrating the great promise of p-MC electrode for practical applications.展开更多
Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/...Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/Mo_(2)CT_(x))to enhance the hydrogen evolution reaction(HER)and supercapacitor activities via an ionic liquid-mediated method.Se vacancy pairs and heteroatom doping enable the reallocation of local electron states and add active sites,improving the electrochemical activity of NBF-CoSe/Mo_(2)CT_(x) with high HER activities over a broad range of pH.At a current density of 10 mA cm^(-2),overvoltages of 70 and 81 mV are respectively produced in 0.5 M H_(2)SO_(4)and 1 M KOH.The optimal structure also exhibits outstanding electrochemical performance in an asymmetric supercapacitor with an energy density of 34.2 Wh kg^(-1)at a power density of 15989.6Wkg^(-1).This study opens new avenues for the introduction of Se vacancies and heteroatom doping to improve the application performance.展开更多
High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional(2D) materials have attr...High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional(2D) materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.展开更多
Flexible electrodes with superior mechanical and electrochemical properties are essential for flexible supercapacitors.A convenient and scalable colloidal film-assisted chemical vapor deposition(CF-CVD)method is devel...Flexible electrodes with superior mechanical and electrochemical properties are essential for flexible supercapacitors.A convenient and scalable colloidal film-assisted chemical vapor deposition(CF-CVD)method is developed for the one-step fabrication of the carbon microspheres films composed of carbon nano-onions(CMS-CNO films).The influence of growth conditions(such as growth temperature,time,and gas ratio)during CF-CVD process on the carbon structures and the growth mechanism of the CMS-CNO films have been investigated.By controlling the growth conditions,the controllable preparation of CMS-CNO films is realized.Such binder-free films can be used for the assembly of flexible supercapacitors,and unique architecture can achieve excellent performance.Benefitting from the composite of nano-micro zero dimensional structures,the performance of the film in supercapacitors is remarkably improved.At the current density of 5 mA cm^(-2),the area-specific capacity can be 903 mF cm^(-2).When the current density is increased to 500 mA cm^(-2),the area-specific capacity can be increased to 729 mF cm^(-2).This simple and low-cost preparation process and the superb electrochemical performance suggest great potential applications of CMS-CNO films in flexible supercapacitors.展开更多
Flexible and wearable fiber electrodes with high conductivity and acceptable electrochemical behavior are crucial for extending the application of nextgeneration portable electronics,the development of which,however,i...Flexible and wearable fiber electrodes with high conductivity and acceptable electrochemical behavior are crucial for extending the application of nextgeneration portable electronics,the development of which,however,is very challenging.Two‐dimensional sheets are known to be excellent units for assembling fiber entities,particularly when sheets are oriented in a stacking manner,which helps integrate their intrinsic in‐plane advantages,especially those related with mechanical and electronic performances.In this study,we developed a flexible macroscopic and continuous fiber in an unusual ribbon shape composed solely of Ti3C2 sheets,a typical member of the MXene family.The ribbon morphology was realized through highly ordered stacking of Ti3C2,which imparts fibers with favorable mechanical characteristics.Based on the intrinsic metallic conductivity of Ti3C2 sheets and the oriented stacking structure,the developed macroscopic ribbon exhibited excellent conductivity for both electrons(up to 2458 S/cm)and ions.A fiber‐shaped asymmetric supercapacitor using the developed macroscopic ribbon as a cathode coupled with reduced graphene oxide fibers as an anode delivered a competitive maximum volumetric energy density of 58.4mWh/cm3(20.0Wh/kg)while maintaining a power level of 1679.0mW/cm3(581.0 W/kg)and excellent cycling stability(92.4%retention after 10000 cycles at 10 A/g).This study highlights the excellent potential of MXene as a platform for macroscopic assembly and definitely broadens the applications of MXene materials in wearable electronics.展开更多
Hydrogel electrolytes hold great potential in flexible zinc ion supercapacitors(ZICs)due to their high conductivity,good safety,and flexibility.However,freezing of electrolytes at low temperature(subzero)leads to dras...Hydrogel electrolytes hold great potential in flexible zinc ion supercapacitors(ZICs)due to their high conductivity,good safety,and flexibility.However,freezing of electrolytes at low temperature(subzero)leads to drastic reduction in ionic conductivity and mechanical properties that deteriorates the performance of flexible ZICs.Besides,the mechanical fracture during arbitrary deformations significantly prunes out the lifespan of the flexible device.Herein,a Zn^(2+)and Li^(+)co-doped,polypyrrole-dopamine decorated Sb_(2)S_(3)incorporated,and polyvinyl alcohol/poly(N-(2-hydroxyethyl)acrylamide)double-network hydrogel electrolyte is constructed with favorable mechanical reliability,anti-freezing,and self-healing ability.In addition,it delivers ultra-high ionic conductivity of 8.6 and 3.7 S m^(-1)at 20 and−30°C,respectively,and displays excellent mechanical properties to withstand tensile stress of 1.85 MPa with tensile elongation of 760%,together with fracture energy of 5.14 MJ m^(-3).Notably,the fractured hydrogel electrolyte can recover itself after only 90 s of infrared illumination,while regaining 83%of its tensile strain and almost 100%of its ionic conductivity during−30–60°C.Moreover,ZICs coupled with this hydrogel electrolyte not only show a wide voltage window(up to 2 V),but also provide high energy density of 230 Wh kg^(-1)at power density of 500 W kg^(-1)with a capacity retention of 86.7%after 20,000 cycles under 20°C.Furthermore,the ZICs are able to retain excellent capacity even under various mechanical deformation at−30°C.This contribution will open up new insights into design of advanced wearable flexible electronics with environmental adaptability and long-life span.展开更多
Construction of advanced electrode materials with unique performance for supercapacitors(SCs)is essential to achieving high implementation in the commercial market.Here,we report a novel peripheral octamethyl-substitu...Construction of advanced electrode materials with unique performance for supercapacitors(SCs)is essential to achieving high implementation in the commercial market.Here,we report a novel peripheral octamethyl-substituted nickel(Ⅱ)phthalocyanine(Ni Me_(2)Pc)-based nanocomposite as the electrode material of all-solid-state SCs.The highly redox-active NiMe_(2)Pc/carboxylated carbon nanotube(CNTCOOH)dendritic nanocomposite provides rapid electron/electrolyte ion-transport pathways and exhibits excellent structural stability,resulting in high-capacity activity and impressive cycling stability.The composite prepared with the optimized weight ratio of Ni Me_(2)Pc:CNT-COOH(6:10)showed the highest specific capacitance of 330.5 F g^(-1)at 0.25 A g^(-1).The constructed NiMe_(2)Pc/CNT-COOH-based all-solid-state symmetric SC device showed excellent performance with a maximum energy density of 22.8 Wh kg^(-1)and outstanding cycling stability(111.6%retained after 35,000 cycles).Moreover,flexible carbon cloth significantly enhanced the energy density of the NiMe_(2)Pc/CNT-COOH all-solid-state symmetric device to 52.1 Wh kg^(-1)with 95.4%capacitance retention after 35,000 cycles,and it could be applied to highperformance flexible electronics applications.These findings provide a novel strategy to design phthalocyanine-based electrode materials for next-generation flexible SC devices.展开更多
Together with the development of high-performance advanced electronics,flexible supercapacitors(SCs)with tailored nanostructures have great attraction.Electrochemically deposited nanosheet arrays of nickel magnesium s...Together with the development of high-performance advanced electronics,flexible supercapacitors(SCs)with tailored nanostructures have great attraction.Electrochemically deposited nanosheet arrays of nickel magnesium selenide(NixMg3-xSe4,NMgS)with high capacitance provide high potentials as a positive electrode in flexible SCs.To further enhance their electrochemical properties and long-term cycling stability,a promising strategy of surface engineering with conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)is proposed.The present work proposes the construction of PEDOT shielded NMgS(P@NMgS-2)on a flexible carbon cloth substrate via a hierarchical electrodeposition technique.Benefitting from the synergistic effect,the P@NMgS-2 exhibits an excellent areal capacitance value of 1440 mF cm^(-2)at 4 mA cm^(-2).A novel shape-adaptable polymer gel electrolyte-assisted flexible quasi-solid-state hybrid SC(FQHSC)device constructed with P@NMgS-2 as a positive electrode and activated carbon as a negative electrode demonstrates the maximum power and energy density values of 14.13 mW cm^(-2)and 0.18 mWh cm^(-2),respectively,followed by outstanding cycling stability(∼100%capacitance retention over 50,000 cycles).Furthermore,the FQHSC device successfully powered electronic devices with no serious degradation upon bending and twisting for wearable electronic applications.展开更多
High conductivity two-dimensional(2D)materials have been proved to be potential electrode materials for flexible supercapacitors because of its outstanding chemical and physical properties.However,electrodes based on ...High conductivity two-dimensional(2D)materials have been proved to be potential electrode materials for flexible supercapacitors because of its outstanding chemical and physical properties.However,electrodes based on 2D materials always suffer from limited electrolyte-accessible surface due to the restacking of the 2D sheets,hindering the full utilization of their surface area.In this regard,an electrolyte-mediated method is used to integrate dense structure reduced graphene oxide/MXene(RGM)-electrolyte composite films.In such composite films,reduced graphene oxide(RGO)and MXene sheets are controllable assembly in compact layered structure with electrolyte filled between the layers.The electrolyte layer between RGO and MXene sheets forms continuous ion transport channels in the composite films.Therefore,the RGM-electrolyte composite films can be used directly as self-supporting electrodes for supercapacitors without additional conductive agents and binders.As a result,the composite films demonstrate enhanced volumetric specific capacity,improved volumetric energy density and higher power density compared with both pure RGO electrode and porous composite electrode prepared by traditional methods.Specifically,when the mass ratio of MXene is 30%,the electrode delivers a volumetric specific capacity of 454.9 F·cm^(−3) with a high energy density of 39.4 Wh·L^(−1).More importantly,supercapacitors based on the composite films exhibit good flexibility electrochemical performance.The investigation provides a new approach to synthesize dense structure films based on 2D materials for application in high volumetric capacitance flexible supercapacitors.展开更多
Since carbon nanotubes(CNTs) possess unique one dimensional(1D) structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D fil...Since carbon nanotubes(CNTs) possess unique one dimensional(1D) structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D films, and 3D foams. Such macroscopic CNT materials exhibit high conductivity, large surface area, as well as good mechanical properties, and thus can be directly used as the flexible supercapacitor(SC) electrodes or the scaffolds for supporting pseudo-capacitive electrode materials. Based on these macroscopic CNT electrodes, diverse SCs with different structures, including flexible, stretchable and/or compressible fiber and thin film SCs, have been designed. This review provides an overview of recent progress towards the development of flexible SCs based on macroscopic CNTs-based electrodes, with a focus on electrode preparation and configuration design as well as their integration with other multifunctional devices.Future development and prospects in the CNTs-based flexible SCs are also discussed.展开更多
In the past few years,supercapacitors(SCs)have attracted great attention in both academic and industrial sectors due to their high energy storage efficiency,reliable stability,and eco-friendly process.Flexible solid-s...In the past few years,supercapacitors(SCs)have attracted great attention in both academic and industrial sectors due to their high energy storage efficiency,reliable stability,and eco-friendly process.Flexible solid-state SCs as one of the ongoing focuses for the development of wearable and portable electronics have become the most promising energy storage devices for the smart power system due to their high power density,fast electrochemical response,high efficiency on the charge-discharge process,and excellent electrochemical stability.In this study,the recent progress in the electrodes and electrolytes used for approaching high-performance of the all-solid-state flexible SCs is reviewed.We first introduce basic operational principles of various SCs.And then we overview the electrode materials including carbon materials,conducting polymers,transition metal oxides/chalcogenides/nitrides,MXenes,metal-organic frameworks,covalent-organic frameworks,and the polymer-based solid-state electrolytes in different systems.Afterward,we summarize recent progress in the development of the all-solid-state flexible SCs and outlook for future research directions.展开更多
CoSn(OH)6 nanocubes were synthesized by a facile one-step co-precipitate method. Their supercapacitor performances were investigated via a traditional threeelectrode system and all solid-state flexible asymmetric su...CoSn(OH)6 nanocubes were synthesized by a facile one-step co-precipitate method. Their supercapacitor performances were investigated via a traditional threeelectrode system and all solid-state flexible asymmetric supercapacitor. The electrode shows a maximum specific capacitance up to 695 F·g^-1. The flexible all solid-state asymmetric supercapacitor was fabricated based on CoSn(OH)6 nanocubes and active carbon as positive and negative electrode. The assembled asymmetric supercapacitor exhibits a specific capacitance(97.3 mF·cm^-2), good rate/mechanical stability and a long cycling stability(5000 cycles), demonstrating great promise for applications in all solid-state flexible supercapacitors.展开更多
Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials...Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.展开更多
Given the rise in the popularity of wearable electronics that are able to deform into desirable configurations while maintaining electrochemical functionality,stretchable and flexible(hybrid)supercapacitors(SCs)have b...Given the rise in the popularity of wearable electronics that are able to deform into desirable configurations while maintaining electrochemical functionality,stretchable and flexible(hybrid)supercapacitors(SCs)have become increasingly of interest as innovative energy storage devices.Their outstanding power density,long lifetime with low capacitance loss,and appropriate energy density,in particular in hybrid cases make them ideal candidates for flexible electronics.The aim of this review paper is to provide an in-depth discussion of these stretchable and flexible SCs ranging from fabrication to electro-mechanical properties.This review paper begins with a short overview of the fundamentals of charge storage mechanisms and different types of multivalent metal-ion hybrid SCs.The research methods leading up to the current state of these stretchable and flexible SCs are then presented.This is followed by an in-depth presentation of the challenges associated with the fabrication methods for different configurations.Proposed novel strategies to maximize the elastic and electrochemical properties of stretchable/flexible or quasi-solid-state SCs are classified and the pros and cons associated with each are shown.The advances in mechanical properties and the expected advancements for the future of these SCs are discussed in the last section.展开更多
<p style="margin-left:10.0pt;"> <span style="font-family:Verdana;"><span style="font-family:Verdana;">We present the electrical and supercapacitive performance of graphe...<p style="margin-left:10.0pt;"> <span style="font-family:Verdana;"><span style="font-family:Verdana;">We present the electrical and supercapacitive performance of graphene nanoplatelets in polymer nanocomposites and flexible solid state electrical double layer capacitors (EDLC) respectively. Graphene-doped poly</span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">(3,4-ethylenedioxythiophene) (PEDOT) coated polyethylene terephthalate (PET) and glass exhibited transmittance above 95% and electrical conductivity of 2.70 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> and 9.01 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> respectively. Graphene loaded polymethyl methacrylate (PMMA) and polystyrene (PS) nanocomposites showed electrical conductivity as high as 2.11 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> at low loadings of 2</span></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">wt%. The use of graphene was necessitated by the need to increase the EDLC capacitance and energy density since it provides high effective surface area. The polymer gel membrane made from polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP) and the Ionic Liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate exhibited high porosity which made it suitable for use as separator in the EDLC. The highes</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">t recorded specific capacitance was 133.82 F/g which can be attributed to the porosity of the IL containing PVDF-co-HFP membrane and the large surface area of the graphene electrodes. At an operating voltage of 3.5 V the energy density was found to be 56.92 Wh<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>Kg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">. All chemicals were research grade and were obtained from Sigma Aldrich.</span></span></span></span> </p>展开更多
A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive el...A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).展开更多
Solid-state and quasi-solid-state electrolytes have been attracting the scientific community’s attention in the last decade. These electrolytes provide significant advantages, such as the absence of leakage and separ...Solid-state and quasi-solid-state electrolytes have been attracting the scientific community’s attention in the last decade. These electrolytes provide significant advantages, such as the absence of leakage and separators for devices and safety for users. They also allow the assembly of stretchable and bendable supercapacitors. Comparing solid-state to quasi-solid-states, the last provides the most significant energy and power densities due to the better ionic conductivity. Our goal here is to present recent advances on quasisolid-state electrolytes, including gel-polymer electrolytes. We reviewed the most recent literature on quasi-solid-state electrolytes with different solvents for supercapacitors. Organic quasi-solid-state electrolytes need greater attention once they reach an excellent working voltage window greater than 2.5 V.Meanwhile, aqueous-based solid-state electrolytes have a restricted voltage window to less than 2 V. On the other hand, they are easier to handle, provide greater ionic conductivity and capacitance. Recent water-in-salt polymer-electrolytes have shown stability as great as 2 V encouraging further development in aqueous-based quasi-solid-state electrolytes. Moreover, hydrophilic conductive polymers have great commercial appeal for bendable devices. Thus, these electrolytes can be employed in flexible and bendable devices, favoring the improvement of portable electronics and wearable devices(376 references were evaluated and summarized here).展开更多
Flexible supercapacitors are promising energy storage devices in wearable smart electronics. Exploring cost-efficient electrodes with high capacitance would promote the wide-scale application of such capacitors. Herei...Flexible supercapacitors are promising energy storage devices in wearable smart electronics. Exploring cost-efficient electrodes with high capacitance would promote the wide-scale application of such capacitors. Herein, in order to explore a methodology for preparing low cost, flexible, tough, and up-scalable supercapacitor electrodes, silk textile is directly carbonized to make a conductive free-standing textile substrate. Through mildly baking the surfactant-free TiCTflakes suspension loaded on the carbonized silk cloth, a uniform and adhesive coating consisting of nanometer-thick TiCTflakes is well established on the conductive fabric support, forming a MXene-coated flexible textile electrode. The fabricated electrode exhibits a high areal capacitance of 362 m F/cm~2 with excellent cyclability and flexibility. Moreover,capacitance changes neglegibly under the bending deformation mode. This study elucidates the feasibility of using silk-derived carbon cloth from biomss for MXene-based flexible supercapacitor.展开更多
Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current co...Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current collectors are expensive and fragile.Moreover,the poor interface between active material and current collector leads to unsatisfactory stability.Herein,these two issues are attempted to be solved by using cheap and lightweight polyester-based fabrics as well as in-situ growth.A deposited thin layer of nickel on the fabrics not only enhances the conductivity,but also serves as the sacrificial precursor for the growth of active materials.Thus,intimate contact is secured via chemical bonding.The electrode with ternary(metalinorganic-organic)component shows excellent electrochemical performance.Namely,high areal capacity is realized(2.2 C cm^(-2)at 2 mA cm^(-2)),which is far superior to its rigid nickel-foam-based counterpart.Furthermore,an allsolid-state supercapacitor device was assembled.The device provides an areal capacity of 2.03 C cm^(-2)at the current density of 2 mA cm^(-2).It realizes an energy density of 0.45 mWh cm^(-2)when the power density is 1.6 mW cm^(-2).This work offers a feasible and cost-efficient way for fabricating electrode materials with excellent performance for portable supercapacitors.展开更多
The deposition of active materials directly onto metal wires is a general strategy to prepare wire-shaped electrodes for flexible and wearable energy storage devices. However, it is still a critical challenge to coat ...The deposition of active materials directly onto metal wires is a general strategy to prepare wire-shaped electrodes for flexible and wearable energy storage devices. However, it is still a critical challenge to coat active materials onto the aimed metal wires because of their smooth surface and small specific surface area. In this work, high porous nickel yarns(PNYs) was fabricated using commercial nylon yarns as templates through step-wise electroless plating, electroplating and calcination processes. The PNYs are composed of multiplied fibers with hollow tubular structure of 5–10 μm in diameter, allowing the imbibition of carbon nanotubes(CNTs) solution by a facile capillary action process. The prepared CNTs/PNY electrodes showed a typical electrochemical double layer capacitive performance and the constructed allsolid flexible wire-shaped symmetric supercapacitors provided a specific capacitance of 4.67 F/cm3 with good cycling stability at a current density of 0.6 A/cm3.展开更多
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Grant Nos.21805261 and 51972277)Sichuan Science and Technology Program(Grant Nos.2021YFG0251 and 2022YFG0293)Fundamental Research Funds for the Central Universities(Grant No.2682021CX105)。
文摘2D MXene(Ti_(3)CNT_(x))has been considered as the most promising electrode material for flexible supercapacitors owing to its metallic conductivity,ultra-high capacitance,and excellent flexibility.However,it suffers from a severe restacking problem during the electrode fabrication process,limiting the ion transport kinetics and the accessibility of ions in the electrodes,especially in the direction normal to the electrode surface.Herein,we report a NH_(3)-induced in situ etching strategy to fabricate 3D-interconnected porous MXene/carbon dots(p-MC)films for high-performance flexible supercapacitor.The pre-intercalated carbon dots(CDs)first prevent the restacking of MXene to expose more inner electrochemical active sites.The partially decomposed CDs generate NH_(3)for in situ etching of MXene nanosheets toward 3D-interconnected p-MC films.Benefiting from the structural merits and the 3D-interconnected ionic transmission channels,p-MC film electrodes achieve excellent gravimetric capacitance(688.9 F g^(-1)at 2 A g^(-1))and superior rate capability.Moreover,the optimized p-MC electrode is assembled into an asymmetric solid-state flexible supercapacitor with high energy density and superior cycling stability,demonstrating the great promise of p-MC electrode for practical applications.
基金supported by the National Natural Science Foundation of China(21905069)the Shenzhen Science and Technology Innovation Committee(JCYJ20180507183907224 and KQTD20170809110344233)the Economic,Trade and Information Commission of Shenzhen Municipality through the Graphene Manufacture Innovation Center(201901161514)。
文摘Vacancy engineering is a useful methodology in the development of catalysts and electrode materials.Herein,we report the introduction of Se-vacancy pairs in heteroatom-doped(N,B,and F)CoSe/Mo_(2)CT_(x) MXene(NBF-CoSe/Mo_(2)CT_(x))to enhance the hydrogen evolution reaction(HER)and supercapacitor activities via an ionic liquid-mediated method.Se vacancy pairs and heteroatom doping enable the reallocation of local electron states and add active sites,improving the electrochemical activity of NBF-CoSe/Mo_(2)CT_(x) with high HER activities over a broad range of pH.At a current density of 10 mA cm^(-2),overvoltages of 70 and 81 mV are respectively produced in 0.5 M H_(2)SO_(4)and 1 M KOH.The optimal structure also exhibits outstanding electrochemical performance in an asymmetric supercapacitor with an energy density of 34.2 Wh kg^(-1)at a power density of 15989.6Wkg^(-1).This study opens new avenues for the introduction of Se vacancies and heteroatom doping to improve the application performance.
基金Funding from the Australian Research Council Centre of Excellence Scheme(CE 140100012)the funding from National Natural Science Foundation of China(51502206)+1 种基金the CSC scholarship from the Ministry of Education of PR Chinathe support of the CSC scholarship from the Ministry of Education of PR China
文摘High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional(2D) materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.
基金the Tianjin Science and Technology Project(18PTZWHZ000,2019JCQNJC05600)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(2019KJ092)the Doctor Foundation(043135202-XB1709)of Tianjin Normal University.
文摘Flexible electrodes with superior mechanical and electrochemical properties are essential for flexible supercapacitors.A convenient and scalable colloidal film-assisted chemical vapor deposition(CF-CVD)method is developed for the one-step fabrication of the carbon microspheres films composed of carbon nano-onions(CMS-CNO films).The influence of growth conditions(such as growth temperature,time,and gas ratio)during CF-CVD process on the carbon structures and the growth mechanism of the CMS-CNO films have been investigated.By controlling the growth conditions,the controllable preparation of CMS-CNO films is realized.Such binder-free films can be used for the assembly of flexible supercapacitors,and unique architecture can achieve excellent performance.Benefitting from the composite of nano-micro zero dimensional structures,the performance of the film in supercapacitors is remarkably improved.At the current density of 5 mA cm^(-2),the area-specific capacity can be 903 mF cm^(-2).When the current density is increased to 500 mA cm^(-2),the area-specific capacity can be increased to 729 mF cm^(-2).This simple and low-cost preparation process and the superb electrochemical performance suggest great potential applications of CMS-CNO films in flexible supercapacitors.
基金This study was supported by the National Natural Science Foundation of China(Grant no.51772201)Jiangsu Specially‐Appointed Professor Programand a project funded by the Priority Academic Program Developmentof Jiangsu Higher Education Institutions.
文摘Flexible and wearable fiber electrodes with high conductivity and acceptable electrochemical behavior are crucial for extending the application of nextgeneration portable electronics,the development of which,however,is very challenging.Two‐dimensional sheets are known to be excellent units for assembling fiber entities,particularly when sheets are oriented in a stacking manner,which helps integrate their intrinsic in‐plane advantages,especially those related with mechanical and electronic performances.In this study,we developed a flexible macroscopic and continuous fiber in an unusual ribbon shape composed solely of Ti3C2 sheets,a typical member of the MXene family.The ribbon morphology was realized through highly ordered stacking of Ti3C2,which imparts fibers with favorable mechanical characteristics.Based on the intrinsic metallic conductivity of Ti3C2 sheets and the oriented stacking structure,the developed macroscopic ribbon exhibited excellent conductivity for both electrons(up to 2458 S/cm)and ions.A fiber‐shaped asymmetric supercapacitor using the developed macroscopic ribbon as a cathode coupled with reduced graphene oxide fibers as an anode delivered a competitive maximum volumetric energy density of 58.4mWh/cm3(20.0Wh/kg)while maintaining a power level of 1679.0mW/cm3(581.0 W/kg)and excellent cycling stability(92.4%retention after 10000 cycles at 10 A/g).This study highlights the excellent potential of MXene as a platform for macroscopic assembly and definitely broadens the applications of MXene materials in wearable electronics.
基金supported by the National Natural Science Foundation of China(52174247 and 22302066)“Hejian”Innovative Talent Project of Hunan Province(No.2022RC1088)+1 种基金the Hunan Provincial Natural Science Foundation(2023JJ40255)the Scientific Research Foundation of Hunan Provincial Education(22B0599 and 23A0442)。
文摘Hydrogel electrolytes hold great potential in flexible zinc ion supercapacitors(ZICs)due to their high conductivity,good safety,and flexibility.However,freezing of electrolytes at low temperature(subzero)leads to drastic reduction in ionic conductivity and mechanical properties that deteriorates the performance of flexible ZICs.Besides,the mechanical fracture during arbitrary deformations significantly prunes out the lifespan of the flexible device.Herein,a Zn^(2+)and Li^(+)co-doped,polypyrrole-dopamine decorated Sb_(2)S_(3)incorporated,and polyvinyl alcohol/poly(N-(2-hydroxyethyl)acrylamide)double-network hydrogel electrolyte is constructed with favorable mechanical reliability,anti-freezing,and self-healing ability.In addition,it delivers ultra-high ionic conductivity of 8.6 and 3.7 S m^(-1)at 20 and−30°C,respectively,and displays excellent mechanical properties to withstand tensile stress of 1.85 MPa with tensile elongation of 760%,together with fracture energy of 5.14 MJ m^(-3).Notably,the fractured hydrogel electrolyte can recover itself after only 90 s of infrared illumination,while regaining 83%of its tensile strain and almost 100%of its ionic conductivity during−30–60°C.Moreover,ZICs coupled with this hydrogel electrolyte not only show a wide voltage window(up to 2 V),but also provide high energy density of 230 Wh kg^(-1)at power density of 500 W kg^(-1)with a capacity retention of 86.7%after 20,000 cycles under 20°C.Furthermore,the ZICs are able to retain excellent capacity even under various mechanical deformation at−30°C.This contribution will open up new insights into design of advanced wearable flexible electronics with environmental adaptability and long-life span.
基金supported by the National Natural Science Foundation of China(Grant Nos.21975116 and 51950410598)the Major Program of Guangdong Basic and Applied Research(Grant No.2019B121205001)+2 种基金Shenzhen NSQKJJ(Grant No.K20799112)the Shenzhen Science and Technology Innovation Committee(Project No.JCYJ20170412154426330)the‘‘Climbing Program”Special Funds(Project No.pdjh2021c0027)。
文摘Construction of advanced electrode materials with unique performance for supercapacitors(SCs)is essential to achieving high implementation in the commercial market.Here,we report a novel peripheral octamethyl-substituted nickel(Ⅱ)phthalocyanine(Ni Me_(2)Pc)-based nanocomposite as the electrode material of all-solid-state SCs.The highly redox-active NiMe_(2)Pc/carboxylated carbon nanotube(CNTCOOH)dendritic nanocomposite provides rapid electron/electrolyte ion-transport pathways and exhibits excellent structural stability,resulting in high-capacity activity and impressive cycling stability.The composite prepared with the optimized weight ratio of Ni Me_(2)Pc:CNT-COOH(6:10)showed the highest specific capacitance of 330.5 F g^(-1)at 0.25 A g^(-1).The constructed NiMe_(2)Pc/CNT-COOH-based all-solid-state symmetric SC device showed excellent performance with a maximum energy density of 22.8 Wh kg^(-1)and outstanding cycling stability(111.6%retained after 35,000 cycles).Moreover,flexible carbon cloth significantly enhanced the energy density of the NiMe_(2)Pc/CNT-COOH all-solid-state symmetric device to 52.1 Wh kg^(-1)with 95.4%capacitance retention after 35,000 cycles,and it could be applied to highperformance flexible electronics applications.These findings provide a novel strategy to design phthalocyanine-based electrode materials for next-generation flexible SC devices.
基金This work was supported by the National Research Foundation of Korea Grant funded by the Korea government(MSIP)(No.2018R1A6A1A03025708 and No.2020R1A2B5B01002318).
文摘Together with the development of high-performance advanced electronics,flexible supercapacitors(SCs)with tailored nanostructures have great attraction.Electrochemically deposited nanosheet arrays of nickel magnesium selenide(NixMg3-xSe4,NMgS)with high capacitance provide high potentials as a positive electrode in flexible SCs.To further enhance their electrochemical properties and long-term cycling stability,a promising strategy of surface engineering with conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)is proposed.The present work proposes the construction of PEDOT shielded NMgS(P@NMgS-2)on a flexible carbon cloth substrate via a hierarchical electrodeposition technique.Benefitting from the synergistic effect,the P@NMgS-2 exhibits an excellent areal capacitance value of 1440 mF cm^(-2)at 4 mA cm^(-2).A novel shape-adaptable polymer gel electrolyte-assisted flexible quasi-solid-state hybrid SC(FQHSC)device constructed with P@NMgS-2 as a positive electrode and activated carbon as a negative electrode demonstrates the maximum power and energy density values of 14.13 mW cm^(-2)and 0.18 mWh cm^(-2),respectively,followed by outstanding cycling stability(∼100%capacitance retention over 50,000 cycles).Furthermore,the FQHSC device successfully powered electronic devices with no serious degradation upon bending and twisting for wearable electronic applications.
基金This work was supported by the Natural Science Foundation of Shandong Province(Nos.ZR2018BB038 and ZR2019BEM041)the National Natural Science Foundation of China(Nos.21805171,51802178 and 51804189).
文摘High conductivity two-dimensional(2D)materials have been proved to be potential electrode materials for flexible supercapacitors because of its outstanding chemical and physical properties.However,electrodes based on 2D materials always suffer from limited electrolyte-accessible surface due to the restacking of the 2D sheets,hindering the full utilization of their surface area.In this regard,an electrolyte-mediated method is used to integrate dense structure reduced graphene oxide/MXene(RGM)-electrolyte composite films.In such composite films,reduced graphene oxide(RGO)and MXene sheets are controllable assembly in compact layered structure with electrolyte filled between the layers.The electrolyte layer between RGO and MXene sheets forms continuous ion transport channels in the composite films.Therefore,the RGM-electrolyte composite films can be used directly as self-supporting electrodes for supercapacitors without additional conductive agents and binders.As a result,the composite films demonstrate enhanced volumetric specific capacity,improved volumetric energy density and higher power density compared with both pure RGO electrode and porous composite electrode prepared by traditional methods.Specifically,when the mass ratio of MXene is 30%,the electrode delivers a volumetric specific capacity of 454.9 F·cm^(−3) with a high energy density of 39.4 Wh·L^(−1).More importantly,supercapacitors based on the composite films exhibit good flexibility electrochemical performance.The investigation provides a new approach to synthesize dense structure films based on 2D materials for application in high volumetric capacitance flexible supercapacitors.
基金supported by the MOST (Ministry of Science and Technology of China) (No. 2017YFA0206701)NSFC (National Natural Science Foundation of China) (Nos. 51602218, 21573116, 11604242)+1 种基金MOE (Ministry of Education of China) (No. B12015)Tianjin Basic and High-Tech Development (No. 15JCYBJC17300)
文摘Since carbon nanotubes(CNTs) possess unique one dimensional(1D) structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D films, and 3D foams. Such macroscopic CNT materials exhibit high conductivity, large surface area, as well as good mechanical properties, and thus can be directly used as the flexible supercapacitor(SC) electrodes or the scaffolds for supporting pseudo-capacitive electrode materials. Based on these macroscopic CNT electrodes, diverse SCs with different structures, including flexible, stretchable and/or compressible fiber and thin film SCs, have been designed. This review provides an overview of recent progress towards the development of flexible SCs based on macroscopic CNTs-based electrodes, with a focus on electrode preparation and configuration design as well as their integration with other multifunctional devices.Future development and prospects in the CNTs-based flexible SCs are also discussed.
文摘In the past few years,supercapacitors(SCs)have attracted great attention in both academic and industrial sectors due to their high energy storage efficiency,reliable stability,and eco-friendly process.Flexible solid-state SCs as one of the ongoing focuses for the development of wearable and portable electronics have become the most promising energy storage devices for the smart power system due to their high power density,fast electrochemical response,high efficiency on the charge-discharge process,and excellent electrochemical stability.In this study,the recent progress in the electrodes and electrolytes used for approaching high-performance of the all-solid-state flexible SCs is reviewed.We first introduce basic operational principles of various SCs.And then we overview the electrode materials including carbon materials,conducting polymers,transition metal oxides/chalcogenides/nitrides,MXenes,metal-organic frameworks,covalent-organic frameworks,and the polymer-based solid-state electrolytes in different systems.Afterward,we summarize recent progress in the development of the all-solid-state flexible SCs and outlook for future research directions.
基金financially supported by the Program for New Century Excellent Talents of the University in China (No. NCET-13-0645)the National Natural Science Foundation of China (Nos. 21201010, 21671170 and 21673203)+3 种基金the Innovation Scientists and Technicians Troop Construction Projects of Henan Province (No. 164200510018)the Program for Innovative Research Team (in Science and Technology) in University of Henan Province (No. 14IRTSTHN004)the Six Talent Plan (No. 2015-XCL-030)Qinglan Project
文摘CoSn(OH)6 nanocubes were synthesized by a facile one-step co-precipitate method. Their supercapacitor performances were investigated via a traditional threeelectrode system and all solid-state flexible asymmetric supercapacitor. The electrode shows a maximum specific capacitance up to 695 F·g^-1. The flexible all solid-state asymmetric supercapacitor was fabricated based on CoSn(OH)6 nanocubes and active carbon as positive and negative electrode. The assembled asymmetric supercapacitor exhibits a specific capacitance(97.3 mF·cm^-2), good rate/mechanical stability and a long cycling stability(5000 cycles), demonstrating great promise for applications in all solid-state flexible supercapacitors.
基金supported by the National Key Research and Development Program of China(grant SQ2019YFE012189,grant2017YFB0307001)the National Natural Science Foundation of China(grants 51973093,U1533122,and 51773094)+5 种基金the Natural Science Foundation of Tianjin(grant number 18JCZDJC36800)the National Special Support Plan for High-level Talents people(grant number C041800902)the Science Foundation for Distinguished Young Scholars of Tianjin(grant number 18JCJQJC46600)the Frontiers Science Center for New Organic Matter(Grant Number 63181206)the Fundamental Research Funds for the Central Universities(grant 63171219)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(grant LK1704)。
文摘Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.
文摘Given the rise in the popularity of wearable electronics that are able to deform into desirable configurations while maintaining electrochemical functionality,stretchable and flexible(hybrid)supercapacitors(SCs)have become increasingly of interest as innovative energy storage devices.Their outstanding power density,long lifetime with low capacitance loss,and appropriate energy density,in particular in hybrid cases make them ideal candidates for flexible electronics.The aim of this review paper is to provide an in-depth discussion of these stretchable and flexible SCs ranging from fabrication to electro-mechanical properties.This review paper begins with a short overview of the fundamentals of charge storage mechanisms and different types of multivalent metal-ion hybrid SCs.The research methods leading up to the current state of these stretchable and flexible SCs are then presented.This is followed by an in-depth presentation of the challenges associated with the fabrication methods for different configurations.Proposed novel strategies to maximize the elastic and electrochemical properties of stretchable/flexible or quasi-solid-state SCs are classified and the pros and cons associated with each are shown.The advances in mechanical properties and the expected advancements for the future of these SCs are discussed in the last section.
文摘<p style="margin-left:10.0pt;"> <span style="font-family:Verdana;"><span style="font-family:Verdana;">We present the electrical and supercapacitive performance of graphene nanoplatelets in polymer nanocomposites and flexible solid state electrical double layer capacitors (EDLC) respectively. Graphene-doped poly</span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">(3,4-ethylenedioxythiophene) (PEDOT) coated polyethylene terephthalate (PET) and glass exhibited transmittance above 95% and electrical conductivity of 2.70 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> and 9.01 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> respectively. Graphene loaded polymethyl methacrylate (PMMA) and polystyrene (PS) nanocomposites showed electrical conductivity as high as 2.11 × 10<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> at low loadings of 2</span></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">wt%. The use of graphene was necessitated by the need to increase the EDLC capacitance and energy density since it provides high effective surface area. The polymer gel membrane made from polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP) and the Ionic Liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate exhibited high porosity which made it suitable for use as separator in the EDLC. The highes</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">t recorded specific capacitance was 133.82 F/g which can be attributed to the porosity of the IL containing PVDF-co-HFP membrane and the large surface area of the graphene electrodes. At an operating voltage of 3.5 V the energy density was found to be 56.92 Wh<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>Kg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">. All chemicals were research grade and were obtained from Sigma Aldrich.</span></span></span></span> </p>
基金supported by National Natural Science Foundation of China(21376105 and 21576113)Foshan Innovative and Entepreneurial Research Team Program(No.2014IT100062)
文摘A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles).
基金the funding agencies FAPESP(2014/02163-7,2017/11958-1,2020/14968-0)and CNPq(PQ-2 grant:Process 131234/2020-0&310544/2019-0)the funding from Shell and the importance of the support provided by the ANP(Brazil’s National Oil,Natural Gas,and Biofuels Agency)by the R&D levy regulation。
文摘Solid-state and quasi-solid-state electrolytes have been attracting the scientific community’s attention in the last decade. These electrolytes provide significant advantages, such as the absence of leakage and separators for devices and safety for users. They also allow the assembly of stretchable and bendable supercapacitors. Comparing solid-state to quasi-solid-states, the last provides the most significant energy and power densities due to the better ionic conductivity. Our goal here is to present recent advances on quasisolid-state electrolytes, including gel-polymer electrolytes. We reviewed the most recent literature on quasi-solid-state electrolytes with different solvents for supercapacitors. Organic quasi-solid-state electrolytes need greater attention once they reach an excellent working voltage window greater than 2.5 V.Meanwhile, aqueous-based solid-state electrolytes have a restricted voltage window to less than 2 V. On the other hand, they are easier to handle, provide greater ionic conductivity and capacitance. Recent water-in-salt polymer-electrolytes have shown stability as great as 2 V encouraging further development in aqueous-based quasi-solid-state electrolytes. Moreover, hydrophilic conductive polymers have great commercial appeal for bendable devices. Thus, these electrolytes can be employed in flexible and bendable devices, favoring the improvement of portable electronics and wearable devices(376 references were evaluated and summarized here).
基金supported by the Youth Innovation Promotion Association,Chinese Academy of Sciences(CAS)under grant no.2011152Shenyang National Laboratory for Materials Science,Institute of Metal Research,CAS,under grant no.2017RP06
文摘Flexible supercapacitors are promising energy storage devices in wearable smart electronics. Exploring cost-efficient electrodes with high capacitance would promote the wide-scale application of such capacitors. Herein, in order to explore a methodology for preparing low cost, flexible, tough, and up-scalable supercapacitor electrodes, silk textile is directly carbonized to make a conductive free-standing textile substrate. Through mildly baking the surfactant-free TiCTflakes suspension loaded on the carbonized silk cloth, a uniform and adhesive coating consisting of nanometer-thick TiCTflakes is well established on the conductive fabric support, forming a MXene-coated flexible textile electrode. The fabricated electrode exhibits a high areal capacitance of 362 m F/cm~2 with excellent cyclability and flexibility. Moreover,capacitance changes neglegibly under the bending deformation mode. This study elucidates the feasibility of using silk-derived carbon cloth from biomss for MXene-based flexible supercapacitor.
基金supported by National Natural Science Foundation of China(21801200 and 22075217)National Key Research and Development Program of China(No.2018YFB1502001)+2 种基金the Innovative Research Funds of Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHD2020-001)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University(JDGD-202020)the Fundamental Research Funds for Central Universities(2021ⅣA137)。
文摘Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current collectors are expensive and fragile.Moreover,the poor interface between active material and current collector leads to unsatisfactory stability.Herein,these two issues are attempted to be solved by using cheap and lightweight polyester-based fabrics as well as in-situ growth.A deposited thin layer of nickel on the fabrics not only enhances the conductivity,but also serves as the sacrificial precursor for the growth of active materials.Thus,intimate contact is secured via chemical bonding.The electrode with ternary(metalinorganic-organic)component shows excellent electrochemical performance.Namely,high areal capacity is realized(2.2 C cm^(-2)at 2 mA cm^(-2)),which is far superior to its rigid nickel-foam-based counterpart.Furthermore,an allsolid-state supercapacitor device was assembled.The device provides an areal capacity of 2.03 C cm^(-2)at the current density of 2 mA cm^(-2).It realizes an energy density of 0.45 mWh cm^(-2)when the power density is 1.6 mW cm^(-2).This work offers a feasible and cost-efficient way for fabricating electrode materials with excellent performance for portable supercapacitors.
基金supported by Priority Academic Program Development of Jiangsu Higher Education Institutions (YX03001)Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM)+3 种基金Synergistic Innovation Center for Organic Electronics and Information Displays, Jiangsu Provincial NSF (BK20160890, BK20141424, BK20150863)Jiangsu Province "Six Talent Peak" (2014-XCL-014)Qing Lan Project of Jiangsu ProvinceScientific Research Foundation of NUPT (NY214183, NY215014, NY215152)
文摘The deposition of active materials directly onto metal wires is a general strategy to prepare wire-shaped electrodes for flexible and wearable energy storage devices. However, it is still a critical challenge to coat active materials onto the aimed metal wires because of their smooth surface and small specific surface area. In this work, high porous nickel yarns(PNYs) was fabricated using commercial nylon yarns as templates through step-wise electroless plating, electroplating and calcination processes. The PNYs are composed of multiplied fibers with hollow tubular structure of 5–10 μm in diameter, allowing the imbibition of carbon nanotubes(CNTs) solution by a facile capillary action process. The prepared CNTs/PNY electrodes showed a typical electrochemical double layer capacitive performance and the constructed allsolid flexible wire-shaped symmetric supercapacitors provided a specific capacitance of 4.67 F/cm3 with good cycling stability at a current density of 0.6 A/cm3.