The Origin of the Reduced Reductive Stability of Ion–Solvent Complexes on Alkali and Alkaline Earth Metal Anodes

Abstract The intrinsic instability of organic electrolytes seriously impedes practical applications of high‐capacity metal (Li, Na) anodes. Ion–solvent complexes can even promote the decomposition of electrolytes on metal anodes. Herein, first‐principles calculations were performed to investigate the origin of the reduced reductive stability of ion–solvent complexes. Both ester and ether electrolyte solvents are selected to interact with Li + , Na + , K + , Mg 2+ , and Ca 2+ . The LUMO energy levels of ion–ester complexes exhibit a linear relationship with the binding energy, regulated by the ratio of carbon atomic orbital in the LUMO, while LUMOs of ion–ether complexes are composed by the metal atomic orbitals. This work shows why ion–solvent complexes can reduce the reductive stability of electrolytes, reveals different mechanisms for ester and ether electrolytes, and provides a theoretical understanding of the electrolyte–anode interfacial reactions and guidance to electrolyte and metal anode design.