More generally, it has been proposed that the reduction and oxidation potential of the solid electrolyte upon lithiation/delithiation is a more accurate measure of the practical electrochemical stability window because the energetics of the reaction intermediates and nonequilibrium states are captured . The stability window based on the oxidation and reduction potentials was found to be larger compared to thermodynamic calculations and matched the experimentally measured oxidation and reduction voltages for argyrodite-type Li6PS5Cl, garnet-type Li7La3Zr2O12 and NASICON-type Li1.5Al0.5Ge1.5(PO4)3 (ref. ). For Li3YBr6, this method proposes a stability window between 0-3.43 V vs. Li/Li + (ref. ) (compared to the predicted window of 0.59-3.15V vs Li/Li + ). For Li3YCl6, no data is available.