The chemical stability of an interface is determined by evaluating the "spontaneity" of the reaction triggered upon contact of the anolyte and catholyte materials. Eq. 1 defines the decomposition reaction forming n decomposition products based on a given anolyte/catholyte pair. This reaction is accompanied by a reaction enthalpy ∆H in kJ mol -1 (implying one mole of total reactants). Thus, the spontaneity of Eq. 1 is entirely determined by the change in Gibbs free energy, which is approximated in the rest of this letter by ∆H. Thus, a decomposition reaction is spontaneous when ∆H < 0, and more negative the value of ∆H, the greater the thermodynamic driving force for decomposition. We monitor the magnitude of ∆H as the main descriptor to quantify the chemical stability of an interface.