Recent research advances of self-discharge in supercapacitors: Mechanisms and suppressing strategies

Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation, flexible electronic devices, aerospace, etc. However, the existed self-discharge that is the spontaneous voltage decay after supercapacitors are fully charged, brings about the wide gap between experimental studies and practical utilization of supercapacitors. Although eliminating the self discharge completely is not reachable, suppressing the self-discharge rate to the lowest point is possible and feasible. So far, the significant endeavors have been devoted to achieve this goal. Herein, we summary and discuss the possible mechanisms for the self-discharge and the underlying influence factors. Moreover, the strategies to suppress the self-discharge are systemically summed up by three independent but unified aspects: modifying the electrode, modulating the electrolyte and tuning the separator. Finally, the major challenges to suppress the self-discharge of supercapacitors are concluded and the promising strategies are also pointed out and discussed. This review is presented with the view of serving as a guideline to suppress the self-discharge of supercapacitors and to across-the-board facilitate their widespread application. CO 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Supercapacitors are promising energy storage devices in various fields, but the issue of self-discharge poses a challenge to their practical utilization. While complete elimination of self-discharge may not be achievable, efforts to suppress it through electrode modification, electrolyte modulation, and separator tuning have been made.