Flexible Energy‐Storage Devices: Design Consideration and Recent Progress

Flexible energy‐storage devices are attracting increasing attention as they show unique promising advantages, such as flexibility, shape diversity, light weight, and so on; these properties enable applications in portable, flexible, and even wearable electronic devices, including soft electronic products, roll‐up displays, and wearable devices. Consequently, considerable effort has been made in recent years to fulfill the requirements of future flexible energy‐storage devices, and much progress has been witnessed. This review describes the most recent advances in flexible energy‐storage devices, including flexible lithium‐ion batteries and flexible supercapacitors. The latest successful examples in flexible lithium‐ion batteries and their technological innovations and challenges are reviewed first. This is followed by a detailed overview of the recent progress in flexible supercapacitors based on carbon materials and a number of composites and flexible micro‐supercapacitors. Some of the latest achievements regarding interesting integrated energy‐storage systems are also reviewed. Further research direction is also proposed to surpass existing technological bottle‐necks and realize idealized flexible energy‐storage devices.