Poly(oxetane)-based Electrolytes with Nitrile Groups for All Solid-state Rechargeable Lithium Batteries

Abstract

Solid polymer electrolytes, the electrolytes without a flammable solvent, can solve a safety problem of rechargeable lithium (Li) batteries. We prepared poly(oxetane) with nitrile groups, P(CYAMEO), by ring-opening polymerization of the oxetane derivative and used it for a matrix of solid polymer electrolytes. Charge-discharge performance of the Li|P(CYAMEO)-based electrolyte|LiCoO₂ cells was tested under constant current charge-discharge cycling condition. The test cells with the P(CYAMEO)-based electrolyte that contained LiN(CF₃SO₂)₂, showed better discharge performance than those with the electrolytes that contained other Li salts. The polarization behaviors of the Li electrode in the electrolyte suggest that performance of the test cells partially depend on the structure of the solid electrolyte interphase on the Li electrode surface in the P(CYAMEO)-based electrolyte.