Electrospun polymer electrolyte nanocomposites for solid-state energy storage

We report solid-state fabric supercapacitors with polymer electrolyte composites (PEC). The fabric supercapacitors were comprised of a fiber-shape PEC and electrodes. The PEC was formulated by mixing a network-forming polymer, poly(vinylidene fluoride-co-hexafluoropropylene) and a room temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. By using a simple electrospinning technique, we could successfully fabricate a free-standing fiber-shape PEC. The electrospun PEC showed high ionic conductivity of 0.48 mS/cm and mechanical strength of 2.4 MPa. The electrodes were produced by two-step processes consisting of electrospinning and spray coating. By using these spun electrolyte composites and electrodes, fabric supercapacitors with a sandwich structure were fabricated. The resulting device exhibited typical capacitive energy storage characteristics and the measured specific capacitance was 6.72 mF/cm2. Moreover, the device maintains its structure and electrochemical performance under repeated bending stress. This work can offer a new option for developing solid-state energy storage devices for smart textile and wearable electronic applications.