Preparation of chitosan and citric acid crosslinked membrane and its application in quasi-solid supercapacitors

Quasi-solid electrolytes promote the development of safe and flexible energy storage devices. In this work, a chitosan and citric acid crosslinked membrane is prepared by a freeze-thaw cross-linking method, in which the chemical crosslinking of chitosan and citric acid increase the viscoelastic behavior of the polymer membrane, and the freeze-thaw assist freeze drying process to create abundant interconnected open-pores and three-dimensional (3D) network. Due to the good viscoelasticity, excellent electrolyte loading capacity (596%) and high ion conductivity (7.7 x 10(-3) S.cm(-1)), as quasi-solid electrolyte, our proposed chitosan and citric acid crosslinked membrane helps Zn vertical bar CCFT-ZnSO4 vertical bar AC hybrid supercapacitor to delivers wide operating voltage, high specific capacity of 100.5 F.g(-1) and stable cycle life (93% after 1000 cycles), which suggests that our proposed freeze-thaw assisted freeze drying method has great potential in designing quasi-solid state electrolyte for energy storage device.