PNNL

Abstract

Solid-electrolyte interphases is essential for stable cycling of rechargeable batteries. The traditional approach for interphase design follows the decomposition of additives prior to the host electrolyte, which, as governed by the thermodynamic rule, however, inherently limits the viable additives. Here we report a novel approach of catalytic scheme using non-sacrificial additive. This is exemplified by the localized high-concentration electrolytes, where the anodically inert fluoroethylene carbonate (FEC) plays a catalytic role, rather than sacrificing itself, for modifying the chemistry, structure, and formation mechanism of the CEI layers toward enhanced cycling stability. Based on ab initio molecular dynamics simulations, we further reveal that the unexpected activation of the otherwise inert species in the interphase formation is due to the FEC coordinated environment promotion of electronic state fluctuation. The catalyzing paradigm on CEI formation opens up a new avenue for the interphase design through the use of the commonly overlooked, anodically stable compounds.