Monosodium glutamate, an effective electrolyte additive to enhance cycling performance of Zn anode in aqueous battery

The reversibility and stability of Zn anode in aqueous electrolytes are largely limited by uncontrollable dendrite growth and parasitic reactions at the interface. Here, a monosodium glutamate (MSG) electrolyte additive is introduced to reconstruct the Zn anode/electrolyte interface and suppress Zn dendrite growth as well as H2 evolution. The glutamate anions are preferentially adsorbed on the active sites for Zn corrosion and H2 evolution so that these side reactions are largely suppressed. Moreover, the adsorbed glutamate anions can redistribute the Zn2+ ion flux and promote [Zn(H2O)6]2+ desolvation, leading to uniform Zn deposition at low overpotential. Accordingly, long-term cycling stability (> 1700 h at 5 mA cm−2/5 mA h cm−2) with a low voltage hysteresis (< 60 mV) in Zn||Zn symmetric cell is harvested. Even at a high current density of 9.11 mA cm−2 with limited Zn supply (DODZn = 80%), stable Zn deposition is achieved over 460 h. When coupled with NH4V4O10 cathode, the assembled NH4V4O10||Zn cell delivers higher capacity retention of 93.6% after 1000 cycles, compared to only 38.9% capacity retention in the absence of MSG.