Elucidation of the charge-discharge mechanism of lithium/polymer electrolyte/pyrite batteries

The purpose of this work is the elucidation of the charge-discharge mechanism in the all-solid-state lithium/composite polymer electrolyte/pyrite battery operating at 120-135 degreesC. The main focus is the explanation of the unexpected potential jump at 1.85 V during the charge process. Effects on the charge-discharge mechanism of particle size, pyrolysis, alumina addition and Zn doping of the pyrite-based cathode are addressed. Analysis of the experimental data, as well as the structure of the charge-discharge intermediates, diffusion of lithium and iron cations in the composite cathode, suggests that the sudden charge overpotential is associated with slow mass transport of iron(II) cations through the Li2FeS2 phase.