Cross-linked poly(oxetane) matrix for polymer electrolyte containing lithium ions

Oxetane, four-membered cyclic ether provides polymer compounds which have trimethylene oxide (TMO, CH2CH2CH2–O) through its ring-opening polymerization. New gel electrolyte films with TMO and ethylene oxide (EO, CH2CH2–O) chains were prepared. The cross-linked polymer matrixes were prepared from copolymerization of 3-(2-cyanethoxymethyl)-3-ethyloxetane (CMOX) and cross-linker which has oligo-EO chain and two terminal oxetane rings coupled with the EO chain (DDOE or TDOE). The mixture of CMOX, DDOE or TDOE, lithium salt (LiBF4 or lithium bis(trifluoromethanesulfonyl)amide, LiTFSA), propylene carbonate and photo-initiator was irradiated with a high pressure mercury lamp. The maximum conductivity in the gel films prepared from CMOX, TDOE and LiBF4 was 1.52mScm−1 at 353K. Repeatable plating and stripping processes of lithium on a nickel electrode in the gel electrolyte were confirmed by cyclic voltammetry measurement. •Novel gel electrolytes prepared from poly(oxetane) derivatives.•Flexible and transparent gel electrolyte films based cross-linked poly(oxetane) with high conductivity.•Repeatable plating and stripping processes of lithium in the poly(oxetane)-based gel electrolytes were observed.