All-fiber-based quasi-solid-state lithium-ion battery towards wearable electronic devices with outstanding flexibility and self-healing ability

Abstract In recent years, high-performance flexible power sources require not only the improvement for high energy density and power density, but also the reliability and flexibility for practical application. However, the energy storage devices often fail to work and even cause safety problems under deformation, so the effective protection is particularly important. Here, we present a flexible and self-healable all-fiber-based quasi-solid-state lithium-ion battery (LIB). The anode is made up of porous reduced graphene oxide (rGO) fiber with SnO2 quantum dots and the cathode consists of spring-shaped rGO fiber with LiCoO2. The adjustable length of the spring-shaped cathode makes it easy to match the capacity with anode. The fibrous anode and cathode with diameters of 750 µm and 250 µm, respectively, are thick enough to reconnect by visual observation. The LIB can be assembled by the as-prepared cathode, anode and gel polymer together with the self-healing protective shell. The flexible and self-healable LIB has a capacity of 82.6 mAh g−1 under a series of deformation and retains 50.1 mAh g−1 after the 5th healing process at a current density of 0.1 A g−1. This work gives an essential strategy to design LIB for wearable devices.