Exploring innovative synthetic solutions for advanced polymer-based electrochromic energy storage devices:Phenoxazine as a promising chromophore

The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior performer.The polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 cycles.Then,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).Then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 cycles.The energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 h.Also,two EES devices connected in series powered a 3 V LED for almost 30 s.

Layered double hydroxides as electrode materials for flexible energy storage devices

To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.

Bifunctional flexible electrochromic energy storage devices based on silver nanowire flexible transparent electrodes

Flexible electrochromic energy storage devices(FECESDs)for powering flexible electronics have attracted considerable attention.Silver nanowires(AgNWs)are one kind of the most promising flexible transparent electrodes(FTEs)materials for the emerging flexible devices.Currently,fabricating FECESD based on AgNWs FTEs is still hindered by their intrinsic poor electrochemical stability.To address this issue,a hybrid AgNWs/Co(OH)_(2)/PEDOT:PSS electrode is proposed.The PEDOT:PSS could not only improve the resistance against electrochemical corrosion of AgNWs,but also work as functional layer to realize the color-changing and energy storage properties.Moreover,the Co(OH)_(2)interlayer further improved the color-changing and energy storage performance.Based on the improvement,we assembled the symmetrical FECESDs.Under the same condition,the areal capacitance(0.8 mF cm^(−2))and coloration efficiency(269.80 cm^(2)C−1)of AgNWs/Co(OH)_(2)/PEDOT:PSS FECESDs were obviously higher than AgNWs/PEDOT:PSS FECESDs.Furthermore,the obtained FECESDs exhibited excellent stability against the mechanical deformation.The areal capacitance remained stable during 1000 times cyclic bending with a 25 mm curvature radius.These results demonstrated the broad application potential of the AgNWs/Co(OH)_(2)/PEDOT:PSS FECESD for the emerging portable and multifunctional electronics.

In-plane micro-sized energy storage devices:From device fabrication to integration and intelligent designs

The rapid development of micro-electronics raises the demand of their power sources to be simplified,miniaturized and highly integratable with other electronics on a chip.In-plane Micro-sized energy storage devices(MESDs),which are composed of interdigitated electrodes on a single chip,have aroused particular attentions since they could be easily integrated with other miniaturized electronics,reducing the complexity of overall chip design via removing complex interconnections with bulky power sources.This review highlights the achievements in the device fabrication of in-plane MESDs,as well as their integration and intelligent designs.We also discussed the current challenges and future perspectives for the development of in-plane MESDs.

Emerging miniaturized energy storage devices for microsystem applications:from design to integration

The rapid progress of micro/nanoelectronic systems and miniaturized portable devices has tremendously increased the urgent demands for miniaturized and integrated power supplies.Miniaturized energy storage devices(MESDs),with their excellent properties and additional intelligent functions,are considered to be the preferable energy supplies for uninterrupted powering of microsystems.In this review,we aim to provide a comprehensive overview of the background,fundamentals,device configurations,manufacturing processes,and typical applications of MESDs,including their recent advances.Particular attention is paid to advanced device configurations,such as two-dimensional(2D)stacked,2D planar interdigital,2D arbitrary-shaped,three-dimensional planar,and wire-shaped structures,and their corresponding manufacturing strategies,such as printing,scribing,and masking techniques.Additionally,recent developments in MESDs,including microbatteries and microsupercapacitors,as well as microhybrid metal ion capacitors,are systematically summarized.A series of on-chip microsystems,created by integrating functional MESDs,are also highlighted.Finally,the remaining challenges and future research scope on MESDs are discussed.

A focus review on 3D printing of wearable energy storage devices

Three-dimensional(3D)printing has gained popularity in a variety of applications,particularly in the manufacture of wearable devices.Aided by the large degree of freedom in customizable fabrication,3D printing can cater towards the practical requirements of wearable devices in terms of light weight and flexibility.In particular,this focus review aims to cover the important aspect of wearable energy storage devices(WESDs),which is an essential component of most wearable devices.Herein,the topics discussed are the fundamentals of 3D printing inks used,the optimizing strategies in improving the mechanical and electrochemical properties of wearable devices and the recent developments and challenges of wearable electrochemical systems such as batteries and supercapacitors.It can be expected that,with the development of 3D printing technology,realization of the full potential of WESDs and seamless integration into smart devices also needs further in-depth investigations.

Flexible energy storage devices for wearable bioelectronics

With the growing market of wearable devices for smart sensing and personalized healthcare applications,energy storage devices that ensure stable power supply and can be constructed in flexible platforms have attracted tremendous research interests.A variety of active materials and fabrication strategies of flexible energy storage devices have been intensively studied in recent years,especially for integrated self-powered systems and biosensing.A series of materials and applications for flexible energy storage devices have been studied in recent years.In this review,the commonly adopted fabrication methods of flexible energy storage devices are introduced.Besides,recent advances in integrating these energy devices into flexible self-powered systems are presented.Furthermore,the applications of flexible energy storage devices for biosensing are summarized.Finally,the prospects and challenges of the self-powered sensing system for wearable electronics are discussed.

3D Printing of Next-generation Electrochemical Energy Storage Devices: from Multiscale to Multimaterial

The increasing energy requirements to power the modern world has driven active research into more advanced electrochemical energy storage devices(EESD)with both high energy densities and power densities.Wide range of newly discovered materials with promising electrochemical properties has shown great potential for next-generation devices,but their performance is normally associated with contradicting demands of thin electrodes and high mass loading that can be hardly achieved for practical applications.Design of three-dimensional(3D)porous electrodes can increase the mass loading while maintaining the effective charge transport even with thick electrodes,which has proven to be efficient to overcome the limitations.3D structures have also been demonstrated excellent structural stability to withstand strong strains and stresses generated during charge/discharge cycle.3D printing,which can fabricate various delicate and complex structural designs,thus offering brand-new opportunities for the rational design and facile construction of next-generation EESDs.The recent developments in 3D printing of next-generation EESDs with high performance are reviewed.Advanced/multiscale electrode structures,such as hierarchically porous structure that can be constructed via high-resolution 3D printing or with post-treatment,are further emphasized.The ability of current 3D printing techniques to fulfill multimaterial printing to fulfill simple packaging will be covered.

Nanogenerator-Based Self-Charging Energy Storage Devices

One significant challenge for electronic devices is that the energy storage devices are unable to provide su cient energy for continuous and long-time operation,leading to frequent recharging or inconvenient battery replacement.To satisfy the needs of next-generation electronic devices for sustainable working,conspicuous progress has been achieved regarding the development for nanogenerator-based self-charging energy storage devices.Herein,the development of the self-charging energy storage devices is summarized.Focus will be on preparation of nanomaterials for Li-ion batteries and supercapacitors,structural design of the nanogenerator-based self-charging energy storage devices,performance testing,and potential applications.Moreover,the challenges and perspectives regarding self-charging energy storage devices are also discussed.

Graphene-based materials for flexible energy storage devices

The booming developments in portable and wearable electronics promote the design of flexible energy storage systems. Flexible supercapacitors and batteries as promising energy storage devices have attracted tremendous attention. As the key component of both supercapacitors and batteries, electrode materials with excellent flexibility should be considered to match with highly flexible energy storage devices. Owing to large surface area, good thermal and chemical stability, high conductivity and mechanical flexibility,graphene-based materials have been widely employed to serve as promising electrodes of flexible energy storage devices. Considerable efforts have been devoted to the fabrication of flexible graphene-based electrodes through a variety of strategies. Moreover, different configurations of energy storage devices based on these active materials are designed. This review highlights flexible graphene-based two-dimensional film and one-dimensional fiber supercapacitors and various batteries including lithium-ion, lithium–sulfur and other batteries. The challenges and promising perspectives of the graphene-based materials for flexible energy storage devices are also discussed.

Recent development of three-dimension printed graphene oxide and MXene-based energy storage devices

The research for three-dimension(3D)printing carbon and carbide energy storage devices has attracted widespread exploration interests.Being designable in structure and materials,graphene oxide(GO)and MXene accompanied with a direct ink writing exhibit a promising prospect for constructing high areal and volume energy density devices.This review not only summarizes the recent advances in 3D printing energy storage devices including printing methods,ink rheological properties,and different energy storage systems,but also discusses the printing methods related to energy storage.In addition,the binder or additive free of two-dimensional carbide materials is quite important for the present electrochemical energy storage devices,which also are presented.

Zinc micro-energy storage devices powering microsystems

The increasing popularity of the Internet of Things and the growing microelectronics market have led to a heightened demand for microscale energy storage devices,such as microbatteries and microsupercapacitors.Although lithium microbatteries have dominated the market,safety concerns arising from incidents like self-ignition and explosions have prompted a shift towards new microscale energy storage devices prioritizing high safety.Zinc-based micro-energy storage devices(ZMSDs),known for their high safety,low cost,and favorable electrochemical performance,are emerging as promising alternatives to lithium microbatteries.However,challenges persist in the fabrication of microelectrodes,electrolyte infusion,device packaging,and integration with microelectronics.Despite these challenges,significant progress has been made over the last decade.This review focuses on the challenges and recent advancements in zinc-based micro-energy storage,offering unique insights into their applications and paving the way for the commercial deployment of high-performance ZMSDs.

Cell architecture designs towards high-energy-density microscale energy storage devices

The rapid growth of miniaturized electronics has led to an urgent demand for microscale energy storage devices(MESDs)to sustainably power the micro electronic devices.However,most MESDs reported to date have suffered from the limited energy densities and shape versatility compared to conventional large-scale counterparts because of the architectural constraints inherent in microfabrication-based cell manufacturing and cell dimension/structure.This review addresses the cell architecture design for MESDs that can achieve both miniaturization and high energy density.We provide a comprehensive overview of five types of cell architectures of MESDs and their fabrication techniques.In addition,to enable practical applications of MESDs,several cell design approaches are presented with the aim of minimizing the inactive parts of the cell and maximizing the performance metrics of MESDs.Finally,we discuss development direction and outlook of MESDs with a focus on materials chemistry,energy-dense electrochemical systems,and cell performance normalization,which will help to expand their applications and manufacturing scalability.

Sensing as the key to the safety and sustainability of new energy storage devices

New energy storage devices such as batteries and supercapacitors are widely used in various fields because of their irreplaceable excellent characteristics.Because there are relatively few monitoring parameters and limited under-standing of their operation,they present problems in accurately predicting their state and controlling operation,such as state of charge,state of health,and early failure indicators.Poor monitoring can seriously affect the performance of energy storage devices.Therefore,to maximize the efficiency of new energy storage devices without damaging the equipment,it is important to make full use of sensing systems to accurately monitor important parameters such as voltage,current,temperature,and strain.These are highly related to their states.Hence,this paper reviews the sensing methods and divides them into two categories:embedded and non-embedded sensors.A variety of measurement methods used to measure the above parameters of various new energy storage devices such as batteries and super-capacitors are systematically summarized.The methods with different innovative points are listed,their advantages and disadvantages are summarized,and the application of optical fiber sensors is emphasized.Finally,the challenges and prospects for these studies are described.The intent is to encourage researchers in relevant fields to study the early warning of safety accidents from the root causes.

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Next-generation electronics that are fused into the human body can play a key role in future intelligent communication,smart healthcare,and human enhancement applications.As a promising energy supply component for smart biointegrated electronics,environment-adaptive electrochemical energy storage(EES)devices with complementary adaptability and functions have garnered huge interest in the past decade.Owing to the advancements in autonomous chemistry,which regulate the constitutional dynamic networks in materials,EES devices have witnessed higher freedom of autonomous adaptability in terms of mechano-adaptable,biocompatibility,and stimuli-response properties for biointegrated and smart applications.In this mini-review,we summarize the recent progress in emerging environmentadaptive EES devices enabled by the constitutional dynamic network of mechanical adaptable materials,biocompatible materials,and stimuli-responsive supramolecular polymer materials.Finally,the challenges and perspectives of autonomous chemistry on the environment-adaptive EES devices are discussed.

Light-Material Interactions Using Laser and Flash Sources for Energy Conversion and Storage Applications

This review provides a comprehensive overview of the progress in light-material interactions(LMIs),focusing on lasers and flash lights for energy conversion and storage applications.We discuss intricate LMI parameters such as light sources,interaction time,and fluence to elucidate their importance in material processing.In addition,this study covers various light-induced photothermal and photochemical processes ranging from melting,crystallization,and ablation to doping and synthesis,which are essential for developing energy materials and devices.Finally,we present extensive energy conversion and storage applications demonstrated by LMI technologies,including energy harvesters,sensors,capacitors,and batteries.Despite the several challenges associated with LMIs,such as complex mechanisms,and high-degrees of freedom,we believe that substantial contributions and potential for the commercialization of future energy systems can be achieved by advancing optical technologies through comprehensive academic research and multidisciplinary collaborations.

Topological Structure-Modulated Collagen Carbon as Two-in-One Energy Storage Configuration toward Ultrahigh Power and Energy Density

Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).

Catalytic effect of carbon-based electrode materials in energy storage devices

The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.

Sustainable wearable energy storage devices self-charged by human-body bioenergy

Charging wearable energy storage devices with bioenergy from human-bodymotions, biofluids, and body heat holds great potential to construct self-powered body-worn electronics, especially considering the ceaseless nature ofhuman metabolic activities. To bridge the gap between human-body bioen-ergy and storage of energy, wearable triboelectric/piezoelectric nanogenerators(TENGs/PENGs), biofuel cells (BFCs), thermoelectric generators (TEGs) havebeen designed to harvest energy from body-motions, biofluids, and body heat,respectively. Researchers have explored various strategies using bioenergy har-vesters to charge wearable supercapacitors and batteries to relieve or even fullyeliminate the recharging process from external power stations, thus, makingwearable electronics more sustainable, autonomous, and user friendly. In thisarticle, we review the advances in the design of sustainable energy storagedevices charged by human-body energy harvesters. The progress in multifunc-tional wearable energy storage devices that cater to the easy integration withhuman-body energy harvesters will be summarized. Then, the focus is laid onthe integrating strategies (single-cell strategy and separated-cell strategy), devicedesign, materials selection, and characteristics of different self-charging human-body energy harvesting-storage systems. Finally, the challenges that impedethe wide application of human-body energy harvesters charged supercapaci-tors/batteries and prospects will be discussed both from materials and structuraldesign aspects.

An overview of deep eutectic solvents:Alternative for organic electrolytes,aqueous systems&ionic liquids for electrochemical energy storage

As the demand for sustainable energy sources continues to rise,the need for efficient and reliable energy storage systems becomes crucial.In order to effectively store and distribute renewable energy,new and innovative solutions must be explored.This review examines the deep eutectic solvents(DESs)as a green,safe,and affordable solution for the electrochemical energy storage and conversion field,offering tremendous opportunities and a promising future.DESs are a class of environment-friendly solvents known for their low toxicity and unique properties,such as their good conductivity,high thermal stability,and nonflammability.This review explores the fundamentals,preparations,and various interactions that often predominate in the formation of DESs,the properties of DESs,and how DESs are better than traditional solvents involving cost-ineffective and unsafe organic electrolytes and ionic liquids as well as inefficient aqueous systems due to low energy density for electrochemical energy storage applications.Then,a particular focus is placed on the various electrochemical applications of DESs,including their role in the electrolytes in batteries/supercapacitors,electropolishing and electrodeposition of metals,synthesis of electrode materials,recycling of electrodes,and their potential for use in CO_(2)capture.The review concludes by exploring the challenges,research gaps,and future potential of DESs in electrochemical applications,providing a comprehensive overview,and highlighting key considerations for their design and use.