Recent progresses in high-energy-density all pseudocapacitive-electrode-materials-based asymmetric supercapacitors

Recently, asymmetric supercapacitors (ASCs) have attracted extensive research interest worldwide for their potential application in emerging energy-related fields. The smart integration of high overall cell operating voltage and large capacitance can be realized in all-pseudocapacitive-electrode-materials-based ASCs. This innovative all-pseudocapacitive-asymmetric design provides a fascinating way to obtain high-energy-density devices with high power rates and also holds huge potential to bridge the gap between dielectric capacitors and rechargeable batteries. In the present review, we mainly summarized the latest contributions and progress in aqueous/non-aqueous faradaic electrode materials including conductive polymers and/or transition metal oxides/sulfides/nitrides/carbides, the operating principles, system design/engineering, and the rational optimization of all-pseudocapacitive ASCs. The intrinsic advantages and disadvantages of these unique ASCs have been elaborately discussed and comparatively evaluated. Finally, some future trends, prospects, and challenges, especially in rate capability and cycling stability, have been presented for advanced next-generation ASCs.