The advance of fiber-shaped lithium ion batteries

With the development of wearable devices, much attention has been paid to the energy supply for these devices. Traditional batteries are not suitable for wearable devices due to their rigidity and high-density. Meanwhile, flexible and lightweight planar batteries cannot be fitted to the fabric well and have poor permeability, which lower the degree of the wearing comfort of the fabric. Therefore, the fiber-shaped lithium ion battery (LIB) becomes one of the best energy storage devices which can solve all the problems mentioned above because of its light-weight, flexibility, weavability and stretchability. However, the capacity of fiber-shaped LIBs is always lower than the capacity of planar batteries because of the low loading of active materials, and the circuit connection will be very complicated in further weaving. In this review article, we introduce the development of the fiber-shaped LIB, summarize the main challenges and finally point out the future direction of this field.