Flexible energy storage devices

Flexible and wearable electronics have the potential to revolutionize future products by allowing for bending, twisting, and stretching without losing functionality. As an essential part, developing flexible energy storage devices (f-ESDs) to power these electronics has become a prominent research area. Over the last two decades, numerous studies have been conducted to fabricate flexible supercapacitors and batteries using strategies of soft materials and soft structures. With a specific focus on flexible lithium batteries (FLBs), this chapter aims to provide a concise overview of the mechanical foundation and effective strategies for fabricating f-ESDs. It will discuss state-of-the-art soft materials, flexible electrodes, and cell configurations used for assembling f-ESDs. By comparing typical examples, the advantages and disadvantages of different strategies will be explored. Lastly, this chapter will address two main challenges faced in the development of f-ESDs: the lack of a standardized benchmark and the trade-off between flexibility and energy density.