High dipole-moment anion-mediated synergistic regulation of ion transport kinetics and interface chemistry for stable zinc electrodes under high depth of discharge

Aqueous zinc–nickel batteries are promising for large-scale energy storage, but their cycle life is severely restricted by zinc dendrite growth and hydrogen evolution reactions (HER), particularly under high depth-of-discharge (DOD). Herein, sodium sulfamate (SS) is introduced to stabilize the zinc anode. The highly polar NH 2 SO 3 − anions reconstruct the local coordination environment, facilitating Zn(OH) 4 2− de-coordination. Under an applied electric field, the orientational polarization of NH 2 SO 3 − generates a dynamic built-in electric field that drives uniform zinc ion flux. Furthermore, NH 2 SO 3 − adsorbs onto the zinc surface via its amino group and electrostatically attracts Zn 2+ via the sulfonate group, constructing a robust protective interface that suppresses parasitic reactions. Consequently, the symmetric cell achieves over 560 h of stable cycling at 17 mA cm −2 (17 mAh cm −2 ). In practical evaluations (N/P = 1), a 1 Ah zinc–nickel pouch cell delivers >750 h at 65% DOD and >250 h at 100% DOD (1.3 A). A scaled-up 5 Ah cell also operates stably for over 720 h at 10 A. This study highlights the dipole effect of anion additives in realizing highly stable, deeply rechargeable aqueous batteries.