An organophosphine oxide redox shuttle additive that delivers long-term overcharge protection for 4 V lithium-ion batteries

Abstract

Redox shuttle additives are used to protect Li-ion batteries from overcharge. Increased operating voltage requires striking a balance between a high redox potential and electrochemical stability. 1,4-Bis[bis(1-methylethyl)phosphinyl]-2,5-dimethoxybenzene (BPDB) exhibits a redox potential of 4.5 V vs. Li/Li⁺ and provides stable overcharge protection for 4 V cells delivering 95 cycles of 100% overcharge ratio.