Despite environmental benignancy, the Zn metal anode for aqueous zinc batteries is still hindered due to the instability of the anode/electrolyte interface, which originates from the electrolyte not having the ability to form a protective solid electrolyte interphase (SEI) on the anode. Herein, an SEI-forming electrolyte based on zinc sulfamate (Zn(NH2SO3)2) is proposed. Specifically, the sulfamate anion can be adsorbed on the anode easily to construct an anion-rich Helmholtz plane. With a lower unoccupied molecular orbital energy, NH2SO3 – would be preferentially electroreduced to form a stable SEI to suppress the parasitic reactions. Significantly, the Zn anode in the proposed electrolyte can achieve a high Coulombic efficiency of 99.65% for over 1000 cycles. Zn|| NH4V4O10 and Zn||I2 full batteries by adopting the sulfamate electrolyte can retain a high capacity retention of 95.0% for more than 5000 cycles at 5 A g–1, and 93.0% capacity retention for more than 100 cycles at 1 A g–1, respectively.

The practical applications of zinc metal batteries are plagued by the dendritic propagation of its metal anodes due to the limited transfer rate of charge and mass at the electrode/electrolyte interphase. To enhance the reversibility of Zn metal, a quasi-solid interphase composed by defective metal–organic framework (MOF) nanoparticles (D-UiO-66) and two kinds of zinc salts electrolytes is fabricated on the Zn surface served as a zinc ions reservoir. Particularly, anions in the aqueous electrolytes could be spontaneously anchored onto the Lewis acidic sites in defective MOF channels. With the synergistic effect between the MOF channels and the anchored anions, Zn2+ transport is prompted significantly. Simultaneously, such quasi-solid interphase boost charge and mass transfer of Zn2+, leading to a high zinc transference number, good ionic conductivity, and high Zn2+ concentration near the anode, which mitigates Zn dendrite growth obviously. Encouragingly, unprecedented average coulombic efficiency of 99.8% is achieved in the Zn||Cu cell with the proposed quasi-solid interphase. The cycling performance of D-UiO-66@Zn||MnO2 (~ 92.9% capacity retention after 2000 cycles) and D-UiO-66@Zn||NH4V4O10 (~ 84.0% capacity retention after 800 cycles) prove the feasibility of the quasi-solid interphase.