Self-discharge of Batteries: Causes, Mechanisms and Remedies

Self-discharge of batteries is a natural, but nevertheless quite unwelcome phenomenon. Because it is driven in its various forms by the same thermodynamic forces as the discharge during intended operation of the device it can only be slowed down by impeding the reaction kinetics of its various steps, i.e. their respective rates of reaction. This approach should be based on a deeper understanding of the various modes and mechanisms of self-discharge, which in turn depends on the battery chemistry, its mode of operation and environmental conditions. Typical examples from representative battery chemistries are presented and observed effects are reviewed. Similarities between battery chemistries and causes of self-discharge are identified; concepts and ideas obtained this way are outlined. As an outcome of a better understanding of both common and system-independent causes and mechanisms of self-discharge as well as chemistry-specific processes approaches to reduce self-discharge are presented. Achieved progress is highlighted.