Combining Electrode Flexibility and Wave‐Like Device Architecture for Highly Flexible Li‐Ion Batteries

Highly flexible Li‐ion batteries are potential materials for futuristic smart wearable devices. However, previously reported flexible batteries depend mainly on electrode flexibility. In this study, a highly flexible Li‐ion battery is developed by combining electrode flexibility and wave‐like device architecture. A Cu‐deposited conductive nonwoven cloth and a carbon nanotube film are used as current collectors to improve the flexibility of electrodes and maintain their good conductivity. The wave‐like structure can release the tensile and compressive strains during bending and prevent the detachment of various layers. In this manner, the battery exhibits high flexibility and good electrochemical performance and presents 92% capacity retention after 2000 times of bending. The open circuit voltage of the battery is also retained after 10 000 times of bending. The as‐prepared flexible Li‐ion battery is integrated with a night running armband. Thus, the proposed battery can be a potential component for wearable electronics.