An extremely durable redox shuttle additive for overcharge protection of lithium-ion batteries

Redox shuttle additives dissolved in the electrolyte of lithium-ion batteries provide cells with intrinsic protection against overcharge, which can induce hazardous consequences such as thermal runaway. Aromatic hydrocarbons in general, and 1,4-dimethoxybenzene (DMB) in particular, are a key family of organic redox shuttle materials, but the limited solubility (<0.1 M) of 1,4-dimethoxybenzene in carbonate-based electrolytes significantly restricts its applicability. Several molecular engineering strategies for improving the solubility (up to 0.4 M) of dimethoxybenzene shuttles have been demonstrated, but often involve taxing synthesis and exhibit limited overcharge cycles at high current. In this paper, we demonstrate a highly soluble (0.6 M) 1,4-dialkoxybenzene shuttle molecule that can survive over 500 overcharge cycles at C/2 rate with 100% overcharge ratio.