Morphology-controlled synthesis and large-scale self-assembly of nanoscale building blocks into complex nanoarchitectures is still a great challenge in nanoscience. In this work, various porous NiO nanostructures are ...Morphology-controlled synthesis and large-scale self-assembly of nanoscale building blocks into complex nanoarchitectures is still a great challenge in nanoscience. In this work, various porous NiO nanostructures are obtained by a simple ammonia precipitation method and we find that the reaction temperature has a significant impact on their microstructures. Nanoflowers and nanoflakes have been obtained at 0 and50, while, weakly self-assembly nanoflowers with nanoflakes are formed at 20. In order to understand the process-structure-property relationship in nanomaterial synthesis and application, the as-prepared NiO is used as supercapacitor electrode materials, and evaluated by electrochemical measurement. The experimental results indicate that the material obtained at lower temperature has higher pseudocapacitance, the specific capacitance of 944, 889 and 410 F/g are reached for the materials prepared at 0, 20 and 50 and further calcined at 300, respectively. While the material obtained at higher temperature has excellent rate capacity. This offers us an opportunity searching for exciting new properties of NiO, and be useful for fabricating functional nanodevices.展开更多
Pseudocapacitive transition metal oxides(PTMOs)have the advantages of high areal capacitance and material density suitable for high-energy supercapacitor devices,but they are typically marred by insufficient rate perf...Pseudocapacitive transition metal oxides(PTMOs)have the advantages of high areal capacitance and material density suitable for high-energy supercapacitor devices,but they are typically marred by insufficient rate performance,which in turn deteriorates cyclic stability at high current levels.Using the example of spinel manganese oxide,herein we demonstrate that a pseudocapacitive oxide electrode of remarkable rate performance and cyclic stability may be realized by adopting oxide nanocrystallites,which are derived based on a novel solution chemistry,and carbon additive(CA)nanoparticles with highly uniform of size distributions.Precisely controlling the particle morphology and size distribution of the active material and conductive additive(CA)in the nanometer range can maximize the density of active material-CA-electrolyte three-phase contact points,thus facilitating synchronized electron and cation flow for the completion of surface faradaic reactions.The resultant Mn3O4 pseudocapacitive electrode exhibits rate capability and cycle stability,including 60%capacity retention at 60 A g-1 and no capacity fade over 100000 cycles under dynamic current densities,far superior to the state-of-the-art PTMO electrodes.The electrode design strategy is in general applicable to pseudocapacitors containing poorly conductive active materials.展开更多
While the past years have witnessed great achievement in pseudocapacitors,the inauguration of electrode materials of high-performance still remains a formidable challenge.Moreover,the capacity and rate capability of t...While the past years have witnessed great achievement in pseudocapacitors,the inauguration of electrode materials of high-performance still remains a formidable challenge.Moreover,the capacity and rate capability of the electrode depends largely on its electrical conductivity,which ensures fast charge transfer kinetics in both the grain bulk and grain boundaries.Here,nickel hydroxides with oxygen vacancies are facilely fabricated via a hydrothermal method.The active materials exhibit a high specific capacitance of 3250 F·g^(−1)and a high areal of capacitance of 14.98 F·cm^(−2)at 4.6 mA·cm^(−2).The asymmetric supercapacitor device based on our material delivers a high energy density of~71.6 Wh·kg^(−1)and a power density of~17,300 W·kg^(−1)and could retain~95%of their initial capacitance even after 30,000 cycles.In addition,the defect-rich hydroxides demonstrate higher electrical conductivity as well as dielectric constant,which is responsible for the superior pseudocapacitive performance.Our new scientific strategy in terms of taking the advantages of oxygen vacancies might open up new opportunities for qualified pseudocapacitive materials of overall high performances not only for nickel hydroxides but also for other metal hydroxides/oxides.展开更多
Efficient energy storage devices,i.e.pseudocapacitors,are being intensively pursued to address the environmental and energy crises.Most high-performance pseudocapacitors are based on inorganic materials,while organic ...Efficient energy storage devices,i.e.pseudocapacitors,are being intensively pursued to address the environmental and energy crises.Most high-performance pseudocapacitors are based on inorganic materials,while organic materials with broader synthetic tunability have attracted increasing interest.Despite recent progress,electron-deficient(n-type)organic pseudocapacitive materials for flexible energy storage are highly demanded yet remain largely unexplored.Here a novel set of n-type perylene diimide(PDI)based conjugated microporous polymers(CMPs),namely,CMP-1,CMP-2 and CMP-3,have been created to integrate excellent desirable characteristics as organic pseudocapacitor electrode materials for flexible energy storage.In light of electron-accepting redox-active sites,hierarchically porous structures,as well as amide-linked networks,the PDI-CMPs electrodes displayed n-type pseudocapacitive behaviors with high capacity(139-205 F g^(-1)at 0.5 A g^(-1)),wide and negative biases(-1.0 to 0 V vs.Ag/AgCl),and long cycling stability.CMP-3 consisting of tetraphenylmethane three-dimensional(3D)building block and PDI units demonstrates not only higher capacitance but also better performance stability because of the higher specific surface area and faster diffusion kinetics as compared to its counterpart CMP-1.Asymmetric supercapacitors(SCs)based on CMP-3 and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT/PSS)exhibited wider potential window(1.8 V)and higher capacitance(17.4 m F cm^(-2))compared with symmetric SCs based on PEDOT/PSS electrodes.Notably,CMP-3 also demonstrates attractive potentials as the anode for rechargeable Li-ion batteries.The study sheds light on the fundamental understanding of the key structural parameters that determine their electrochemical and transport properties,thus opening a new door for the rational design of efficient and stable n-type organic electrode materials for flexible energy storage applications.展开更多
MXenes have shown record-breaking redox capacitance in aqueous electrolytes,but in a limited voltage window due to oxidation under anodic potential and hydrogen evolution under high cathodic potential.Coupling Ti3C2Tx...MXenes have shown record-breaking redox capacitance in aqueous electrolytes,but in a limited voltage window due to oxidation under anodic potential and hydrogen evolution under high cathodic potential.Coupling Ti3C2Tx Xene negative electrode with RuO_(2) or carbon-based positive electrodes expanded the voltage window in sulfuric acid electrolyte to about 1.5 V.Here,we present an asymmetric pseudocapacitor using abundant and eco-friendly vanadium doped MnO_(2) as the positive and Ti_(3)C_(2)Tx MXene as the negative electrode in a neutral 1M Li2SO4 electrolyte.This all-pseudocapacitive asymmetric device not only uses a safer electrolyte and is a much less expensive counter-electrode than RuO_(2),but also can operate within a 2.1 V voltage window,leading to a maximum energy density of 46 Wh/kg.This study also demonstrates the possibility of using MXene electrodes to expand the working voltage window of traditional redox-capable materials.展开更多
Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity a...Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity and cycling stability of amorphous Co-B alloy nanoparticles grown on conductive graphene sheets. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. As electrode materials for pseudocapacitors, the amorphous Co-B alloy grown on graphene oxide (Co-B@GO) exhibits a high specific capacitance of 460 F g-1, which is nearly 1.5 times greater than that of bare Co-B nanoparticles at 1 A g-l, The specific capacitance preserved 84% of the initial capacitance even after 1000 cycles at a scan rate of 10 m V-1, suggesting its promising po- tential as pseudocapacitor materials.展开更多
Developing multifunctional energy storage systems with high specific energy, high specific power and long cycling life has been the one of the most important research directions. Compared to batteries and traditional ...Developing multifunctional energy storage systems with high specific energy, high specific power and long cycling life has been the one of the most important research directions. Compared to batteries and traditional capacitors, supercapacitors possess more balanced performance with both high specific power and long cycle-life. Nevertheless, regular supercapacitors can only achieve energy storage without harvesting energy and the energy density is still not very high compared to batteries. Therefore, combining high specific energy and high specific power,long cycle-life and even fast self-charging into one cell has been a promising direction for future energy storage devices. The multifunctional hybrid supercapacitors like asymmetric supercapacitors, batteries/supercapacitors hybrid devices and self-charging hybrid supercapacitors have been widely studied recently. Carbon based electrodes are common materials used in all kinds of energy storage devices due to their fabulous electrical and mechanical properties. In this survey, the research progress of all kinds of hybrid supercapacitors using multiple effects and their working mechanisms are briefly reviewed. And their advantages and disadvantages are discussed. The hybrid supercapacitors have great application potential for portable electronics, wearable devices and implantable devices in the future.展开更多
Electrochemical capacitors(ECs)with unique merits of fast charge/discharge rate and long cyclability are one of the representative electrochemical energy storage systems,possessing wide applications in power electroni...Electrochemical capacitors(ECs)with unique merits of fast charge/discharge rate and long cyclability are one of the representative electrochemical energy storage systems,possessing wide applications in power electronics and automotive transportation,etc.[1,2].Furthermore.展开更多
通过多种电化学测试技术评价了石墨电极在2.3 mol/L H2SO4溶液中的电化学活化工艺及其准电容性能。结果表明,活化工艺宜采用恒电流阶跃技术,最佳工艺参数为:阳极电流密度为200 m A·cm-2,阴极电流密度为-120 m A·cm-2,对应活...通过多种电化学测试技术评价了石墨电极在2.3 mol/L H2SO4溶液中的电化学活化工艺及其准电容性能。结果表明,活化工艺宜采用恒电流阶跃技术,最佳工艺参数为:阳极电流密度为200 m A·cm-2,阴极电流密度为-120 m A·cm-2,对应活化时间分别为300 s和100 s,循环6次。改性后的石墨电极表面形成了多孔、粗糙的三维活性层,单位面积上具有较高的电容量(2.08 F·cm-2)和良好的倍率特性,可作为一种优异的准电容器材料。展开更多
基金financially supported by the National Natural Science Foundation of China (21063014 and 21163021)Fundamental Research Funds for the Central Universities (XDJK2013B031)the Natural Science Foundation of Chongqing (cstc2013jcyj A0396)
文摘Morphology-controlled synthesis and large-scale self-assembly of nanoscale building blocks into complex nanoarchitectures is still a great challenge in nanoscience. In this work, various porous NiO nanostructures are obtained by a simple ammonia precipitation method and we find that the reaction temperature has a significant impact on their microstructures. Nanoflowers and nanoflakes have been obtained at 0 and50, while, weakly self-assembly nanoflowers with nanoflakes are formed at 20. In order to understand the process-structure-property relationship in nanomaterial synthesis and application, the as-prepared NiO is used as supercapacitor electrode materials, and evaluated by electrochemical measurement. The experimental results indicate that the material obtained at lower temperature has higher pseudocapacitance, the specific capacitance of 944, 889 and 410 F/g are reached for the materials prepared at 0, 20 and 50 and further calcined at 300, respectively. While the material obtained at higher temperature has excellent rate capacity. This offers us an opportunity searching for exciting new properties of NiO, and be useful for fabricating functional nanodevices.
基金financially supported by the“Advanced Research Center for Green Materials Science and Technology”from The Featured Area Research Center Program within the framework of the Higher Education Sprout Project by Ministry of Science and Technology in Taiwan under the grants of MOST-108-3017-F-002002,and also of MOST-107-2221-E-002-106-MY3,MOST-108-2119-M-002-010,MOST-107-2923-E-011-002,MOST-108-3116-F-301-001-F
文摘Pseudocapacitive transition metal oxides(PTMOs)have the advantages of high areal capacitance and material density suitable for high-energy supercapacitor devices,but they are typically marred by insufficient rate performance,which in turn deteriorates cyclic stability at high current levels.Using the example of spinel manganese oxide,herein we demonstrate that a pseudocapacitive oxide electrode of remarkable rate performance and cyclic stability may be realized by adopting oxide nanocrystallites,which are derived based on a novel solution chemistry,and carbon additive(CA)nanoparticles with highly uniform of size distributions.Precisely controlling the particle morphology and size distribution of the active material and conductive additive(CA)in the nanometer range can maximize the density of active material-CA-electrolyte three-phase contact points,thus facilitating synchronized electron and cation flow for the completion of surface faradaic reactions.The resultant Mn3O4 pseudocapacitive electrode exhibits rate capability and cycle stability,including 60%capacity retention at 60 A g-1 and no capacity fade over 100000 cycles under dynamic current densities,far superior to the state-of-the-art PTMO electrodes.The electrode design strategy is in general applicable to pseudocapacitors containing poorly conductive active materials.
基金the National Natural Science Foundation of China(No.51972048)Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(No.22567627H)+1 种基金the National Key Research and Development Program of China(No.2022YFB3706300)the National Natural Science Foundation of China(No.U23A20605).
文摘While the past years have witnessed great achievement in pseudocapacitors,the inauguration of electrode materials of high-performance still remains a formidable challenge.Moreover,the capacity and rate capability of the electrode depends largely on its electrical conductivity,which ensures fast charge transfer kinetics in both the grain bulk and grain boundaries.Here,nickel hydroxides with oxygen vacancies are facilely fabricated via a hydrothermal method.The active materials exhibit a high specific capacitance of 3250 F·g^(−1)and a high areal of capacitance of 14.98 F·cm^(−2)at 4.6 mA·cm^(−2).The asymmetric supercapacitor device based on our material delivers a high energy density of~71.6 Wh·kg^(−1)and a power density of~17,300 W·kg^(−1)and could retain~95%of their initial capacitance even after 30,000 cycles.In addition,the defect-rich hydroxides demonstrate higher electrical conductivity as well as dielectric constant,which is responsible for the superior pseudocapacitive performance.Our new scientific strategy in terms of taking the advantages of oxygen vacancies might open up new opportunities for qualified pseudocapacitive materials of overall high performances not only for nickel hydroxides but also for other metal hydroxides/oxides.
基金supported by the National Natural Science Foundation of China(21835003,62004106,21422402,21674050,61904084)the Natural Science Foundation of Jiangsu Province(BE2019120,BK20190737,BK20210601 and BK20190737)+10 种基金the National Key Basic Research Program of China(2014CB648300,2017YFB0404501)China Postdoctoral Science Foundation(2020M671553 and 2021M691652)Program for Jiangsu Specially-Appointed Professor(RK030STP15001)the Six Talent Peaks Project of Jiangsu Province(TDXCL-009)the 333 Project of Jiangsu Province(BRA2017402)the NUPT“1311 Project”Scientific Foundation(NY217169,NY215062,NY217087)the Leading Talent of Technological Innovation of National Ten-Thousands Talents Program of Chinathe Excellent Scientific and Technological Innovative Teams of Jiangsu Higher Education Institutions(TJ217038)the Synergetic Innovation Center for Organic Electronics and Information Displaysthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Efficient energy storage devices,i.e.pseudocapacitors,are being intensively pursued to address the environmental and energy crises.Most high-performance pseudocapacitors are based on inorganic materials,while organic materials with broader synthetic tunability have attracted increasing interest.Despite recent progress,electron-deficient(n-type)organic pseudocapacitive materials for flexible energy storage are highly demanded yet remain largely unexplored.Here a novel set of n-type perylene diimide(PDI)based conjugated microporous polymers(CMPs),namely,CMP-1,CMP-2 and CMP-3,have been created to integrate excellent desirable characteristics as organic pseudocapacitor electrode materials for flexible energy storage.In light of electron-accepting redox-active sites,hierarchically porous structures,as well as amide-linked networks,the PDI-CMPs electrodes displayed n-type pseudocapacitive behaviors with high capacity(139-205 F g^(-1)at 0.5 A g^(-1)),wide and negative biases(-1.0 to 0 V vs.Ag/AgCl),and long cycling stability.CMP-3 consisting of tetraphenylmethane three-dimensional(3D)building block and PDI units demonstrates not only higher capacitance but also better performance stability because of the higher specific surface area and faster diffusion kinetics as compared to its counterpart CMP-1.Asymmetric supercapacitors(SCs)based on CMP-3 and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT/PSS)exhibited wider potential window(1.8 V)and higher capacitance(17.4 m F cm^(-2))compared with symmetric SCs based on PEDOT/PSS electrodes.Notably,CMP-3 also demonstrates attractive potentials as the anode for rechargeable Li-ion batteries.The study sheds light on the fundamental understanding of the key structural parameters that determine their electrochemical and transport properties,thus opening a new door for the rational design of efficient and stable n-type organic electrode materials for flexible energy storage applications.
基金supported by the National Natural Science Foundation of China(Nos.51972124,51902115,and 51872101)supported by King Abdullah University of Science and Technology(KAUST)under the KAUST-Drexel Competitive Research Grant(No.OSR-CRG2016-2963 sub 11206).
文摘MXenes have shown record-breaking redox capacitance in aqueous electrolytes,but in a limited voltage window due to oxidation under anodic potential and hydrogen evolution under high cathodic potential.Coupling Ti3C2Tx Xene negative electrode with RuO_(2) or carbon-based positive electrodes expanded the voltage window in sulfuric acid electrolyte to about 1.5 V.Here,we present an asymmetric pseudocapacitor using abundant and eco-friendly vanadium doped MnO_(2) as the positive and Ti_(3)C_(2)Tx MXene as the negative electrode in a neutral 1M Li2SO4 electrolyte.This all-pseudocapacitive asymmetric device not only uses a safer electrolyte and is a much less expensive counter-electrode than RuO_(2),but also can operate within a 2.1 V voltage window,leading to a maximum energy density of 46 Wh/kg.This study also demonstrates the possibility of using MXene electrodes to expand the working voltage window of traditional redox-capable materials.
基金supported by the University of Minnesota Initiative for Renewable Energy and the Environment(IREE)the Shanghai Municipal Education Commission(High-energy Beam Intelligent Processing and Green Manufacturing)the Characterization Facility,University of Minnesota,which receives partial support from NSF through the MRSEC program
文摘Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity and cycling stability of amorphous Co-B alloy nanoparticles grown on conductive graphene sheets. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. As electrode materials for pseudocapacitors, the amorphous Co-B alloy grown on graphene oxide (Co-B@GO) exhibits a high specific capacitance of 460 F g-1, which is nearly 1.5 times greater than that of bare Co-B nanoparticles at 1 A g-l, The specific capacitance preserved 84% of the initial capacitance even after 1000 cycles at a scan rate of 10 m V-1, suggesting its promising po- tential as pseudocapacitor materials.
基金supported by the National Key Research & Development Program of China (2018YFA0208401)。
文摘Developing multifunctional energy storage systems with high specific energy, high specific power and long cycling life has been the one of the most important research directions. Compared to batteries and traditional capacitors, supercapacitors possess more balanced performance with both high specific power and long cycle-life. Nevertheless, regular supercapacitors can only achieve energy storage without harvesting energy and the energy density is still not very high compared to batteries. Therefore, combining high specific energy and high specific power,long cycle-life and even fast self-charging into one cell has been a promising direction for future energy storage devices. The multifunctional hybrid supercapacitors like asymmetric supercapacitors, batteries/supercapacitors hybrid devices and self-charging hybrid supercapacitors have been widely studied recently. Carbon based electrodes are common materials used in all kinds of energy storage devices due to their fabulous electrical and mechanical properties. In this survey, the research progress of all kinds of hybrid supercapacitors using multiple effects and their working mechanisms are briefly reviewed. And their advantages and disadvantages are discussed. The hybrid supercapacitors have great application potential for portable electronics, wearable devices and implantable devices in the future.
基金financially supported by the National Natural Science Foundation of China(22125903,51872283,22005298)。
文摘Electrochemical capacitors(ECs)with unique merits of fast charge/discharge rate and long cyclability are one of the representative electrochemical energy storage systems,possessing wide applications in power electronics and automotive transportation,etc.[1,2].Furthermore.
文摘通过多种电化学测试技术评价了石墨电极在2.3 mol/L H2SO4溶液中的电化学活化工艺及其准电容性能。结果表明,活化工艺宜采用恒电流阶跃技术,最佳工艺参数为:阳极电流密度为200 m A·cm-2,阴极电流密度为-120 m A·cm-2,对应活化时间分别为300 s和100 s,循环6次。改性后的石墨电极表面形成了多孔、粗糙的三维活性层,单位面积上具有较高的电容量(2.08 F·cm-2)和良好的倍率特性,可作为一种优异的准电容器材料。