Progress and challenges of flexible lithium ion batteries

The research in high performance flexible lithium ion batteries (FLIBs) thrives with the increasing demand in novel flexible electronics such as wearable devices and implantable medical kits. FLIBs share the same working mechanism with traditional LIBs. Meanwhile, FLIBs need to exhibit flexibility and even bendable and stretchable features. The development of FLIBs highly relies on the improvement of flexible electrodes and battery designs to achieve high performance and stability under mechanical deformation. In this review, recent advances and progress on the development of FLIBs are concerned. Two specific research strategies of FLIBs are discussed in detail: preparation of flexible battery components (including electrodes, current collectors, and electrolytes) and flexible structure designs or assembly methods of FLIBs. Finally, challenges and perspectives for developing high performance FLIBs are presented. •The latest progress of flexible lithium batteries (FLIBs) is reviewed.•Two research routes to achieve FLIBs are summarized.•The challenges of FLIBs in material selection and structural design are analyzed.•The key points of future development of FLIBs are listed.