Mechanical fatigue of flexible batteries

Flexible energy storage devices, such as flexible batteries, are essential in powering flexible electronics and face significant performance challenges under mechanical fatigue. This review explores the effects of mechanical fatigue on the electrochemical performance of flexible batteries, specifically analyzing fatigue in battery components and how it impacts the electrochemical parameters as key indicators of energy storage device lifetime. Distinct from electrochemical fatigue, mechanical fatigue in flexible batteries degrades their structural and functional stability. The review covers recent research on testing methods and advances in mechanical modeling and simulation that have been used to assess static and cyclic load impacts. Detailed attention is given to factors such as delamination, crack formation, wrinkling, and contact pressure, which influence the durability of flexible battery components. Microstructural analysis techniques are highlighted for investigating degradation at the interface of active materials and current collectors. Also, it was shown that machine learning is a promising tool for predicting the remaining useful life and improving the design of flexible batteries.