Fire-retardant solid polymer electrolyte films prepared from oxetane derivative with dimethyl phosphate ester group

Fire-retardant polymer electrolytes are key materials for safer operation of lithium secondary batteries and other large-size batteries than the batteries with organic liquid electrolyte. Solid polymer electrolyte systems with fire-retardant polymer matrixes have been investigated in only few cases. We prepare an oxetane derivative with dimethyl phosphate ester group (DPOX). The cross-linked poly(oxetane) matrixes for solid polymer electrolytes are prepared from DPOX and oxetane-based cross-linker (DDOE). DDOE has two oxetane rings at both of the ends of oligo-ethylene oxide chain. Conductivities in the range of 10(-5) S cm(-1) have been obtained for self-extinguishing, ion-conductive cross-linked poly(oxetane) matrix with DPOX and DDOE monomers. Polarization behavior of a lithium electrode in the cross-linked poly(oxetane)-based electrolyte films is also investigated. The polarization curves show some hysteresis character with potential steps, however, deposition and stripping of lithium on the lithium electrode are observed. (C) 2011 Elsevier B.V. All rights reserved.