Sulfurized Composite Interphase Enables a Highly Reversible Zn Anode

Abstract The stability and reversibility of Zn anode can be greatly improved by in situ construction of solid electrolyte interphase (SEI) on Zn surface via a low‐cost design strategy of ZnSO 4 electrolyte. However, the role of hydrogen bond acceptor ‐SO 3 accompanying ZnS formation during SEI reconstruction is overlooked. In this work, we have explored and revealed the new role of ‐SO 3 and ZnS in the in situ formed sulfide composite SEI (SCSEI) on Zn anode electrochemistry in ZnSO 4 aqueous electrolytes. Structure characterization and DFT demonstrate that the introduction of ‐SO 3 can not only reduce the dehydration energy of [Zn(H 2 O) 6 ] 2+ , but also enhance the stability of the ZnS/Zn interface and homogenize the ZnS/Zn interface electric field, thereby significantly improving the dynamic kinetics and uniform deposition of Zn 2+ . Owing to the synergistic effect of ZnS and ‐SO 3 , a high cycling stability of 1500 h with a cumulative‐plated capacity of 7.5 Ah cm −2 at 10 mA cm −2 has been achieved within the symmetrical cell. Furthermore, the full cell with NH 4 V 4 O 10 cathode exhibits outstanding cyclic stability, exceeding 2000 cycles at 5 A g −1 and maintaining a Coulombic efficiency of 100 %. These new insights into anionic synergistic strategy could significantly enhance the practical application of zinc‐ion batteries.