Plastic crystal–solid biopolymer electrolytes for rechargeable lithium batteries

In this paper, solid polymer electrolytes consisting of chitosan, lithium bis (trifluoromethylsulfonyl) imide (LiTFSI) as a salt and succinonitrile as a plastic crystal are prepared by using the solution casting method. Electrochemical impedance spectroscopy is used to examine the ionic conductivity of the films at the temperature range of 303–383 K. Chitosan–LiTFSI containing 50 wt% succinonitrile exhibits high ionic conductivity at a room temperature of 0.4×10−3 S cm−1, a high lithium ion transference number (0.598) and wide electrochemical window. The solid polymer electrolyte with LiFePO4 as a cathode displays a stable discharge capacity of 160 mAh g−1 for up to 50 cycles at a current density of 17 mA g−1. The results demonstrate the potential for the solid polymer electrolyte system to be used as an electrolyte in lithium rechargeable batteries.