Conquering Self-Discharge in Supercapacitors: Synergy of Mechanisms and Cross-Scale Mitigation Strategies

Abstract

Supercapacitors have emerged as increasingly vital energy storage solutions, leveraging exceptional power density, ultralong cycle life, and rapid charge-discharge capabilities.However, their widespread deployment faces a fundamental limitation: inherent selfdischarge phenomena that severely compromise energy retention and long-term reliability in critical applications like flexible electronics, microsystems, and backup power systems. This review systematically categorizes self-discharge mechanismsohmic leakage, Faradaic reactions, and charge redistribution-and critically dissects their physicochemical underpinnings. We comprehensively analyze key governing factors spanning electrode architecture, electrolyte thermodynamics, and dynamic interfacial phenomena. Furthermore, we spotlight breakthrough protection strategies enabled by advanced material engineering, precise electrolyte modulation, and innovative device design. To transcend current barriers, we pioneer novel concepts including "multi-interface synergistic engineering" and "stimuli-responsive smart materials", charting a course toward intelligent supercapacitors with embedded realtime self-discharge diagnostics and adaptive control. Ultimately, this work provides actionable guidelines for designing next-generation supercapacitors with minimized energy loss and enhanced operational resilience.