Self-discharge in rechargeable electrochemical energy storage devices

Self-discharge is one of the limiting factors of energy storage devices, adversely affecting their electrochemical performances. A comprehensive understanding of the diverse factors underlying the self-discharge mechanisms provides a pivotal path to improving the electrochemical performances of the devices. This review focuses on the self-discharge process inherent in various rechargeable electrochemical energy storage devices including rechargeable batteries, supercapacitors, and hybrid ion capacitors. A detailed explanation of the experimental methodologies employed to elucidate self-discharge in different systems is provided. Additionally, diverse models and theoretical frameworks explaining the self-discharge mechanisms across different systems are explored. Finally, the review outlines potential future research direction, offering insights to mitigate self-discharge in different electrochemical energy storage devices intended for long-term storage applications.