Recent Advances in Design of Flexible Electrodes for Miniaturized Supercapacitors

Abstract

The increasing demands of portable, flexible, and wearable electronics have greatly stimulated the development of miniaturized supercapacitors (MSCs) with features of high flexibility, low weight, long lifespan, and safety. The techniques which can effectively incorporate functional nanomaterials into flexible electrodes are extremely important for future wide‐spread applications of MSCs, and thus are identified as the research focus in the field. Herein, this review focuses on recent advances in the fabrication of flexible electrodes and their applications in MSCs. In particular, the principles of the newly developed fiber spinning techniques and their utilization in designing microstructures and resulting electrochemical properties of fibrous electrodes are first described. Second, a few novel approaches to prepare planar MSCs and their special advantages are introduced, and third, the state‐of‐the‐art research in 3D stereo MSCs based on 3D printing and morphing technologies are discussed. In the end, the prospects and key challenges based on the considerations of performance improvement, device design, and system integration are outlined.

Optimization and Preparation of a Gel Polymer Electrolyte Membrane for Supercapacitors

“…Because of their high power density, long cycle life, and excellent stability, supercapacitors have received more attention in recent years 1–4. However, the relatively low energy density limits its further development and application 5–7.…”

Flexible Zn‐ion batteries based on manganese oxides: Progress and prospect

“…Ideally, a low cost, low consumption of power, and environmental‐friendly technique will lead to a real application of the flexible ZIBs. By comparing with recent state‐of‐the‐art flexible devices, several metrics of the flexible batteries for future commercialization are proposed: first, self‐discharging flexible device could be created by integrating the batteries with nanogenerators to convert mechanical energy or solar‐cells to harvest solar energy 120 ; second, highly temperature‐resistant films with large areas would facilitate the real applications in electric vehicles at an extremely cold weather 121 ; third, a facile and large‐scale production method would be necessary for the commercialization, for example, printing techniques would be recommended for producing patterned flexible devices which can be scalable and easily integrated 122 …”

The Jahn-Teller Effect for Amorphization of Molybdenum Trioxide towards High-Performance Fiber Supercapacitor

“…However, the currently utilized bottom-up strategies, for example, solvothermal reaction [ 27 , 28 ], electrochemical deposition [ 26 ], and photochemical deposition [ 29 ], are subjected to numerous issues, including (i) special attention needs be paid to reaction environment (e.g., temperature) to stabilize the metastable amorphous phase, (ii) nonuniform coating resulted from unevenly distributed electric field on electrode surface, (iii) rigorous experimental conditions, e.g., ultraviolet illumination, (iv) possible contamination from organic additives, and (v) complicated procedures which are not suitable for massive preparation. Moreover, these methods are incompatible with the state-of-the-art fiber-spinning techniques [ 30 , 31 ].…”