Hybridization design of materials and devices for flexible electrochemical energy storage

Electrochemical energy storage devices are considered promising flexible energy storage systems because of their high power, fast charging rates, long-term cyclability, and simple configurations. However, the critical issues including low energy density, performance degradation, safety, versatile form factors, and compact device integration should be considered. Herein, we comprehensively review the key aspects of flexible electrochemical energy storage systems with hybrid design from the electrode materials and devices to overcome these impediments and simultaneously achieve both performance and flexibility. We address the fundamental aspects, classification, and design guidelines of flexible hybrid electrochemical energy storage systems in terms of the hybridizations of materials and devices. We finally offer our perspective on the current impediments and future directions to promote continuous innovation and practical application of flexible electrochemical energy storage systems and beyond.