Dynamic shielding of electrified interface enables high-voltage lithium batteries

The electric double layer (EDL) plays a pivotal role in the interfacial reactions that occur within lithium batteries. However, theoretical models beyond the empirical Guy-Chapman-Stern (GCS) model to understand reaction mechanisms and tuning principles are lacking. Herein, we introduce a quantitative parameter of region d within the EDL, which successfully elucidates the correlation between the EDL functional domain and the oxidation resistance of electrolytes. The reduced spatial scale of d results in a rapid decay of interface potential to the bulk level, effectively suppressing the continuous decomposition of the electrolyte. By precisely modulating the functional area represented by d, the designed 1.5 M LiFSI in a (3,3,3-Trifluoropropyl) trimethoxysilane (TFTMS) electrolyte exhibits remarkably high oxidation stability of >5.5 V and enables simultaneous stabilization of Li metal, graphite, and high-voltage layered cathodes. The EDL model incorporated with quantitative functional area d offers a promising path to guide the advancement of high-energy Li batteries.