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1.
Compared with other flexible energy‐storage devices, the design and construction of the compressible energy‐storage devices face more difficulty because they must accommodate large strain and shape deformations. In the present work, CoNi2S4 nanoparticles/3D porous carbon nanotube (CNT) sponge cathode with highly compressible property and excellent capacitance is prepared by electrodepositing CoNi2S4 on CNT sponge, in which CoNi2S4 nanoparticles with size among 10–15 nm are uniformly anchored on CNT, causing the cathode to show a high compression property and gives high specific capacitance of 1530 F g−1. Meanwhile, Fe2O3/CNT sponge anode with specific capacitance of 460 F g−1 in a prolonged voltage window is also prepared by electrodepositing Fe2O3 nanosheets on CNT sponge. An asymmetric supercapacitor (CoNi2S4/CNT//Fe2O3/CNT) is assembled by using CoNi2S4/CNT sponge as positive electrode and Fe2O3/CNT sponge as negative electrode in 2 m KOH solution. It exhibits excellent energy density of up to 50 Wh kg−1 at a power density of 847 W kg−1 and excellent cycling stability at high compression. Even at a strain of 85%, about 75% of the initial capacitance is retained after 10 000 consecutive cycles. The CoNi2S4/CNT//Fe2O3/CNT device is a promising candidate for flexible energy devices due to its excellent compressibility and high energy density.  相似文献   

2.
A carbon nanotube (CNT) sponge contains a three-dimensional conductive nano- tube network, and can be used as a porous electrode for various energy devices. We present here a rational strategy to fabricate a unique CNT@polypyrrole (PPy) core-shell sponge, and demonstrate its application as a highly compressible supercapacitor electrode with high performance. A PPy layer with optimal thickness was coated uniformly on individual CNTs and inter-CNT contact points by electrochemical deposition and crosslinking of pyrrole monomers, resulting in a core-shell configuration. The PPy coating significantly improves specific capacitance of the CNT sponge to above 300 F/g, and simultaneously reinforces the porous structure to achieve better strength and fully elastic structural recovery after compression. The CNT@PPy sponge can sustain 1,000 compression cycles at a strain of 50% while maintaining a stable capacitance (〉 90% of initial value). Our CNT@PPy core-shell sponges with a highly porous network structure may serve as compressible, robust electrodes for supercapacitors and many other energy devices.  相似文献   

3.
Carbon fiber (CF) grafted with a layer of carbon nanotubes (CNTs) plays an important role in composite materials and other fields; to date, the applications of CNTs@CF multiscale fibers are severely hindered by the limited amount of CNTs grafted on individual CFs and the weak interfacial binding force. Here, monolithic CNTs@CF fibers consisting of a 3D highly porous CNT sponge layer with macroscopic‐thickness (up to several millimeters), which is directly grown on a single CF, are fabricated. Mechanical tests reveal high sponge–CF interfacial strength owing to the presence of a thin transitional layer, which completely inhibits the CF slippage from the matrix upon fracture in CNTs@CF fiber–epoxy composites. The porous conductive CNTs@CF hybrid fibers also act as a template for introducing active materials (pseudopolymers and oxides), and a solid‐state fiber‐shaped supercapacitor and a fiber‐type lithium‐ion battery with high performances are demonstrated. These CNTs@CF fibers with macroscopic CNT layer thickness have many potential applications in areas such as hierarchically reinforced composites and flexible energy‐storage textiles.  相似文献   

4.
The rapid development of wearable electronics requires a revolution of power accessories regarding flexibility and energy density. The Li–CO2 battery was recently proposed as a novel and promising candidate for next‐generation energy‐storage systems. However, the current Li–CO2 batteries usually suffer from the difficulties of poor stability, low energy efficiency, and leakage of liquid electrolyte, and few flexible Li–CO2 batteries for wearable electronics have been reported so far. Herein, a quasi‐solid‐state flexible fiber‐shaped Li–CO2 battery with low overpotential and high energy efficiency, by employing ultrafine Mo2C nanoparticles anchored on a carbon nanotube (CNT) cloth freestanding hybrid film as the cathode, is demonstrated. Due to the synergistic effects of the CNT substrate and Mo2C catalyst, it achieves a low charge potential below 3.4 V, a high energy efficiency of ≈80%, and can be reversibly discharged and charged for 40 cycles. Experimental results and theoretical simulation show that the intermediate discharge product Li2C2O4 stabilized by Mo2C via coordinative electrons transfer should be responsible for the reduction of overpotential. The as‐fabricated quasi‐solid‐state flexible fiber‐shaped Li–CO2 battery can also keep working normally even under various deformation conditions, giving it great potential of becoming an advanced energy accessory for wearable electronics.  相似文献   

5.
One of the key challenges of aqueous supercapacitors is the relatively low voltage (0.8–2.0 V), which significantly limits the energy density and feasibility of practical applications of the device. Herein, this study reports a novel Ni–Mn–O solid‐solution cathode to widen the supercapacitor device voltage, which can potentially suppress the oxygen evolution reaction and thus be operated stably within a quite wide potential window of 0–1.4 V (vs saturated calomel electrode) after a simple but unique phase‐transformation electrochemical activation. The solid‐solution structure is designed with an ordered array architecture and in situ nanocarbon modification to promote the charge/mass transfer kinetics. By paring with commercial activated carbon anode, an ultrahigh voltage asymmetric supercapacitor in neutral aqueous LiCl electrolyte is assembled (2.4 V; among the highest for single‐cell supercapacitors). Moreover, by using a polyvinyl alcohol (PVA)–LiCl electrolyte, a 2.4 V hydrogel supercapacitor is further developed with an excellent Coulombic efficiency, good rate capability, and remarkable cycle life (>5000 cycles; 95.5% capacity retention). Only one cell can power the light‐emitting diode indicator brightly. The resulting maximum volumetric energy density is 4.72 mWh cm?3, which is much superior to previous thin‐film manganese‐oxide‐based supercapacitors and even battery–supercapacitor hybrid devices.  相似文献   

6.
Flexible devices integrated with sensing and energy storage functions are highly desirable due to their potential application in wearable electronics and human motion detection. Here, a flexible film is designed in a facile and low‐cost leaf templating process, comprising wrinkled carbon nanotubes (CNTs) as the conductive layer and patterned polydimethylsiloxane (PDMS) with bio‐inspired microstructure as a soft substrate. Assembled from wrinkled CNTs on patterned PDMS film, a strain sensor is realized to possess sensitive resistance response against various deformations, producing a resistance response of 0.34%, 0.14%, and 9.1% under bending, pressing, and 20% strain, respectively. Besides, the strain sensor can reach a resistance response of 3.01 when stretched to 44%. Furthermore, through the electro‐deposition of polyaniline, the CNTs film is developed into a supercapacitor, which exhibits a specific capacitance of 176 F g?1 at 1 A g?1 and a capacitance retention of 88% after 10 000 cycles. In addition, the fabricated supercapacitor shows super flexibility, delivering a capacitance retention of 98% after 180° bending for 100 cycles, 95% after 45° twisting for 100 cycles, and 98% after 100% stretching for 400 cycles. The superior capacitance stability demonstrates that the design of wrinkled CNTs‐based electrodes fixed by microstructures is beneficial to the excellent electrochemical performance.  相似文献   

7.
Yarn supercapacitors are promising power sources for flexible electronic applications that require conventional fabric‐like durability and wearer comfort. Carbon nanotube (CNT) yarn is an attractive choice for constructing yarn supercapacitors used in wearable textiles because of its high strength and flexibility. However, low capacitance and energy density limits the use of pure CNT yarn in wearable high‐energy density devices. Here, transitional metal oxide pseudocapacitive materials NiO and Co3O4 are deposited on as‐spun CNT yarn surface using a simple electrodeposition process. The Co3O4 deposited on the CNT yarn surface forms a uniform hybridized CNT@Co3O4 layer. The two‐ply supercapacitors formed from the CNT@Co3O4 composite yarns display excellent electrochemical properties with very high capacitance of 52.6 mF cm?2 and energy density of 1.10 μWh cm?2. The high performance two‐ply CNT@Co3O4 yarn supercapacitors are mechanically and electrochemically robust to meet the high performance requirements of power sources for wearable electronics.  相似文献   

8.
Flexible supercapacitors have shown enormous potential for portable electronic devices. Herein, hierarchical 3D all‐carbon electrode materials are prepared by assembling N‐doped graphene quantum dots (N‐GQDs) on carbonized MOF materials (cZIF‐8) interweaved with carbon nanotubes (CNTs) for flexible all‐solid‐state supercapacitors. In this ternary electrode, cZIF‐8 provides a large accessible surface area, CNTs act as the electrical conductive network, and N‐GQDs serve as highly pseudocapactive materials. Due to the synergistic effect and hierarchical assembly of these components, N‐GQD@cZIF‐8/CNT electrodes exhibit a high specific capacitance of 540 F g?1 at 0.5 A g?1 in a 1 m H2SO4 electrolyte and excellent cycle stability with 90.9% capacity retention over 8000 cycles. The assembled supercapacitor possesses an energy density of 18.75 Wh kg?1 with a power density of 108.7 W kg?1. Meanwhile, three supercapacitors connected in series can power light‐emitting diodes for 20 min. All‐solid‐state N‐GQD@cZIF‐8/CNT flexible supercapacitor exhibits an energy density of 14 Wh kg?1 with a power density of 89.3 W kg?1, while the capacitance retention after 5000 cycles reaches 82%. This work provides an effective way to construct novel electrode materials with high energy storage density as well as good cycling performance and power density for high‐performance energy storage devices via the rational design.  相似文献   

9.
In addition to a high specific capacitance, a large stretchability and self‐healing properties are also essential to improve the practicality and reliability of supercapacitors in portable and wearable electronics. However, the integration of multiple functions into one device remains challenging. Here, the construction of a highly stretchable and real‐time omni‐healable supercapacitor is demonstrated by sandwiching the polypyrrole‐incorporated gold nanoparticle/carbon nanotube (CNT)/poly(acrylamide) (GCP@PPy) hydrogel electrodes with a CNT‐free GCP (GP) hydrogel as the electrolyte and chemically soldering an Ag nanowire film to the hydrogel electrode as the current collector. The newly developed dynamic metal‐thiolate (M‐SR, M = Au, Ag) bond‐induced integrated configuration, with an intrinsically powerful electrode and electrolyte, enables the assembled supercapacitor to deliver an areal capacitance of 885 mF cm?2 and an energy density of 123 µWh cm?2, which are among the highest‐reported values for stretchable supercapacitors. Notably, the device exhibits a superhigh stretching strain of 800%, rapid optical healing capability, and significant real‐time healability during the charge–discharge process. The exceptional performance combined with the facile assembly method confirms this multifunctional device as the best performer among all the flexible supercapacitors reported to date.  相似文献   

10.
Synaptic electronics is a new technology for developing functional electronic devices that can mimic the structure and functions of biological counterparts. It has broad application prospects in wearable computing chips, human–machine interfaces, and neuron prostheses. These types of applications require synaptic devices with ultralow energy consumption as the effective energy supply for wearable electronics, which is still very difficult. Here, artificial synapse emulation is demonstrated by solid‐ion gated organic field‐effect transistors (OFETs) with a 3D‐interface conducting channel for ultralow‐power synaptic simulation. The basic features of the artificial synapse, excitatory postsynaptic current (EPSC), paired‐pulse facilitation (PPF), and high‐pass filtering, are successfully realized. Furthermore, the single‐fiber based artificial synapse can be operated by an ultralow presynaptic spike down to ?0.5 mV with an ultralow reading voltage at ?0.1 mV due to the large contact surface between the ionic electrolyte and fiber‐like semiconducting channel. Therefore, the ultralow energy consumption at one spike of the artificial synapse can be realized as low as ≈3.9 fJ, which provides great potential in a low‐power integrated synaptic circuit.  相似文献   

11.
Electrochromic devices have been widely adopted in energy saving applications by taking advantage of the electrode coloration, but it is critical to develop a new electrochromic device that can undergo smart coloration and can have a wide spectrum in transmittance in response to input light intensity while also functioning as a rechargeable energy storage system. In this study, a photoresponsive electrochromic supercapacitor based on cellulose‐nanofiber/Ag‐nanowire/reduced‐graphene‐oxide/WO3‐composite electrode that is capable of undergoing “smart” reversible coloration while simultaneously functioning as a reliable energy‐storage device is developed. The fabricated device exhibits a high coloration efficiency of 64.8 cm2 C?1 and electrochemical performance with specific capacitance of 406.0 F g?1, energy/power densities of 40.6–47.8 Wh kg?1 and 6.8–16.9 kW kg?1. The electrochromic supercapacitor exhibits excellent cycle reliability, where 75.0% and 94.1% of its coloration efficiency and electrochemical performance is retained, respectively, beyond 10 000 charge–discharge cycles. Cyclic fatigue tests show that the developed device is mechanically durable and suitable for wearable electronics applications. The smart electrochromic supercapacitor system is then integrated with a solar sensor to enable photoresponsive coloration where the transmittance changes in response to varying light intensity.  相似文献   

12.
Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device‐level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO2 nanowire composites are developed. A supercapacitor edited with honeycomb‐like structure shows a specific capacitance of 227.2 mF cm?2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state‐of‐the‐art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch‐and‐release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices.  相似文献   

13.
Nanocarbon electronic conductors combined with pseudocapacitive materials, such as conducting polymers, display outstanding electrochemical properties and mechanical flexibility. These characteristics enable the fabrication of flexible electrodes for energy‐storage devices; that is, supercapacitors that are wearable or can be formed into shapes that are easily integrated into vehicle parts. To date, most nanocarbon materials such as nanofibers are randomly dispersed as a network in a flexible matrix. This morphology inhibits ion transport, particularly under the high current density necessary for devices requiring high power density. Novel flexible densified horizontally aligned carbon nanotube arrays (HACNTs) with controlled nanomorphology for improved ion transport are introduced and combined with conformally coated poly(3‐methylthiophene) (P3MT) conducting polymer to impart pseudocapacitance. The resulting P3MT/HACNT nanocomposite electrodes exhibit high areal capacitance of 3.1 F cm?2 at 5 mA cm?2, with areal capacitance remaining at 1.8 F cm?2 even at a current density of 200 mA cm?2. The asymmetric supercapacitor cell also delivers more than 1–2 orders of magnitude improvement in both areal energy and power density over state‐of‐the‐art cells. Furthermore, little change in cell performance is observed under high strain, demonstrating the mechanical and electrochemical stability of the electrodes.  相似文献   

14.
Thread‐like electronic devices have attracted great interest because of their potential applications in wearable electronics. To produce high‐performance, thread‐like supercapacitors, a mixture of stable dispersions of single‐walled carbon nanotubes and conducting polyaniline nanowires are prepared. Then, the mixture is spun into flexible yarns with a polyvinyl alcohol outer sheath by a one‐step spinning process. The composite yarns show excellent mechanical properties and high electrical conductivities after sufficient washing to remove surfactants. After applying a further coating layer of gel electrolyte, two flexible yarns are twisted together to form a thread‐like supercapacitor. The supercapacitor based on these two yarns (SWCNTs and PAniNWs) possesses a much higher specific capacitance than that based only on pure SWCNTs yarns, making it an ideal energy‐storage device for wearable electronics.  相似文献   

15.
Stretchable energy‐storage devices receive considerable attention due to their promising applications in future wearable technologies. However, they currently suffer from many problems, including low utility of active materials, limited multidirectional stretchability, and poor stability under stretched conditions. In addition, most proposed designs use one or more rigid components that fail to meet the stretchability requirement for the entire device. Here, an all‐stretchable‐component sodium‐ion full battery based on graphene‐modified poly(dimethylsiloxane) sponge electrodes and an elastic gel membrane is developed for the first time. The battery exhibits reasonable electrochemical performance and robust mechanical deformability; its electrochemical characteristics can be well‐maintained under many different stretched conditions and after hundreds of stretching–release cycles. This novel design integrating all stretchable components provides a pathway toward the next generation of wearable energy devices in modern electronics.  相似文献   

16.
Printing technology can be used for manufacturing stretchable electrodes, which represent essential parts of wearable devices requiring relatively high degrees of stretchability and conductivity. In this work, a strategy for fabricating printable and highly stretchable conductors are proposed by transferring printed Ag ink onto stretchable substrates comprising Ecoflex elastomer and tough hydrogel layers using a water‐soluble tape. The elastic modulus of the produced hybrid film is close to that of the hydrogel layer, since the thickness of Ecoflex elastomer film coated on hydrogel is very thin (30 µm). Moreover, the fabricated conductor on hybrid film is stretched up to 1780% strain. The described transfer method is simpler than other techniques utilizing elastomer stamps or sacrificial layers and enables application of printable electronics to the substrates with low elastic moduli (such as hydrogels). The integration of printed electronics with skin‐like low‐modulus substrates can be applied to make wearable devices more comfortable for human skin.  相似文献   

17.
Under development for next‐generation wearable electronics are flexible, knittable, and wearable energy‐storage devices with high energy density that can be integrated into textiles. Herein, knittable fiber‐shaped zinc–air batteries with high volumetric energy density (36.1 mWh cm?3) are fabricated via a facile and continuous method with low‐cost materials. Furthermore, a high‐yield method is developed to prepare the key component of the fiber‐shaped zinc–air battery, i.e., a bifunctional catalyst composed of atomically thin layer‐by‐layer mesoporous Co3O4/nitrogen‐doped reduced graphene oxide (N‐rGO) nanosheets. Benefiting from the high surface area, mesoporous structure, and strong synergetic effect between the Co3O4 and N‐rGO nanosheets, the bifunctional catalyst exhibits high activity and superior durability for oxygen reduction and evolution reactions. Compared to a fiber‐shaped zinc–air battery using state‐of‐the‐art Pt/C + RuO2 catalysts, the battery based on these Co3O4/N‐rGO nanosheets demonstrates enhanced and stable electrochemical performance, even under severe deformation. Such batteries, for the first time, can be successfully knitted into clothes without short circuits under external forces and can power various electronic devices and even charge a cellphone.  相似文献   

18.
Skin‐like energy devices can be conformally attached to the human body, which are highly desirable to power soft wearable electronics in the future. Here, a skin‐like stretchable fuel cell based on ultrathin gold nanowires (AuNWs) and polymerized high internal phase emulsions (polyHIPEs) scaffolds is demonstrated. The polyHIPEs can offer a high porosity of 80% yet with an overall thickness comparable to human skin. Upon impregnation with electronic inks containing ultrathin (2 nm in diameter) and ultrahigh aspect‐ratio (>10 000) gold nanowires, skin‐like strain‐insensitive stretchable electrodes are successfully fabricated. With such designed strain‐insensitive electrodes, a stretchable fuel cell is fabricated by using AuNWs@polyHIPEs, platinum (Pt)‐modified AuNWs@polyHIPEs, and ethanol as the anode, cathode, and fuel, respectively. The resulting epidermal fuel cell can be patterned and transferred onto skin as “tattoos” yet can offer a high power density of 280 µW cm?2 and a high durability (>90% performance retention under stretching, compression, and twisting). The results presented here demonstrate that this skin‐thin, porous, yet stretchable electrode is essentially multifunctional, simultaneously serving as a current collector, an electrocatalyst, and a fuel host, indicating potential applications to power future soft wearable 2.0 electronics for remote healthcare and soft robotics.  相似文献   

19.
Moore's law predicts the performance of integrated circuit doubles every two years, lasting for more than five decades. However, the improvements of the performance of energy density in batteries lag far behind that. In addition, the poor flexibility, insufficient‐energy density, and complexity of incorporation into wearable electronics remain considerable challenges for current battery technology. Herein, a lithium‐ion cable battery is invented, which is insensitive to deformation due to its use of carbon nanotube (CNT) woven macrofilms as the charge collectors. An ultrahigh‐tap density of 10 mg cm?2 of the electrodes can be obtained, which leads to an extremely high‐energy density of 215 mWh cm?3. The value is approximately seven times than that of the highest performance reported previously. In addition, the battery displays very stable rate performance and lower internal resistance than conventional lithium‐ion batteries using metal charge collectors. Moreover, it demonstrates excellent convenience for connecting electronics as a new strategy is applied, in which both electrodes can be integrated into one end by a CNT macrorope. Such an ultrahigh‐energy density lithium‐ion cable battery provides a feasible way to power wearable electronics with commercial viability.  相似文献   

20.
The development of integrated high‐performance supercapacitors with all‐in‐one configuration, excellent flexibility and autonomously intrinsic self‐healability, and without the extra healable film layers, is still tremendously challenging. Compared to the sandwich‐like laminated structures of supercapacitors with augmented interfacial contact resistance, the flexible healable integrated supercapacitor with all‐in‐one structure could theoretically improve their interfacial contact resistance and energy densities, simplify the tedious device assembly process, prolong the lifetime, and avoid the displacement and delamination of multilayered configurations under deformations. Herein, a flexible healable all‐in‐one configured supercapacitor with excellent flexibility and reliable self‐healing ability by avoiding the extra healable film substrates and the postassembled sandwich‐like laminated structures is developed. The healable all‐in‐one configured supercapacitor is prepared from in situ polymerization and deposition of nanocomposites electrode materials onto the two‐sided faces of the self‐healing hydrogel electrolyte separator. The self‐healing hydrogel film is obtained from the physically crosslinked hydrogel with enormous hydrogen bonds, which can endow the healable capability through dynamic hydrogen bonding. The assembled all‐in‐one configured supercapacitor exhibits enhanced capacitive performance, good cycling stability, reliable self‐healing capability, and excellent flexibility. It holds broad prospects for obtaining various flexible healable all‐in‐one configured supercapacitors for working as portable energy storage devices in wearable electronics.  相似文献   

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