Chloroethoxy-terminated perfluoropolyether electrolytes with high lithium ion transference number for lithium battery applications

Publication date: Available online 20 June 2019Source: PolymerAuthor(s): Yuzhi Feng, Xiaoting Chen, Huige Wei, Yibo Pei, Xudong TangAbstractThis paper reported the synthesis of an organic solvent, chloroethoxy-terminated perfluoropolyether (PFPECH2CH2Cl), which was obtained by reacting hydroxyethoxy-terminated perfluoropolyether with thionyl chloride. Liquid polymer electrolytes were then prepared by solving bis(trifluoromethane)sulfonimide lithium salt in PFPECH2CH2Cl for lithium ion battery applications. The electrolyte exhibits higher lithium-ion transference number (t+ = 0.87), lower glass transition temperature (Tg = −13.3 °C), higher decomposition temperature (Td5% > 210 °C), and wider electrochemical stability window up to 4.3 V (vs. Li/Li+) at a lithium salt concentration of 0.7 mol L−1 (the weight percent is about 10%). Moreover, it is surprisingly found that PFPECH2CH2Cl/LiTFSI electrolyte had excellent redox property in lithium batteries. PFPECH2CH2Cl is proposed to react with Li metal to form PFPECH2CH2Li, which not only promoted the compatibility with lithium, but also increased the concentration of lithium ions, thus facilitating the participation of lithium ions in the electrochemical reactions.Graphical abstractPFPECH2CH2Cl reacted with lithium metal to form PFPECH2CH2Li and LiCl, which not only promoted the compatibility with lithium, but also increased the concentration of lithium ions, thus facilitating the participation of lithi...

Source: Polymer - June 20, 2019 Category: Chemistry Source Type: research