Bolstered Interfacial Field Chemistry for Deep Fast-Charging Aqueous Zinc Metal Batteries

Deep fast-charging capability has become the core pursuit for practical applications of aqueous zinc metal batteries, yet it is critically impeded by unfavorable interfacial field evolution at the electrode/electrolyte interface under high-current-density conditions. The coexistence of sluggish Zn²⁺ desolvation, competitive H₂O reduction corrosion, uneven electric field, and concentration field collectively leads to poor rate performance. To tackle these issues, a bolstered interfacial field chemistry strategy was developed via sulfosuccinic acid to precisely regulate the physicochemical and electrochemical properties within the inner Helmholtz plane. The tuned interfacial field comprises a homogeneous distribution of interfacial ions and electric fields, promoting fast desolvation and interfacial electron transfer. Consequently, the modified Zn||Cu asymmetric cells deliver an outstanding average Coulombic efficiency of 99.48% over 1600 cycles at 2 mA cm^-2 and 1 mAh cm^-2. Furthermore, the modified Zn||Zn symmetric cells demonstrate exceptional stability under challenging conditions of 5 mA cm^-2, 2 mAh cm^-2 (over 1600 h), and 10 mA cm^-2, 10 mAh cm^-2 (over 675 h, depth of discharge = 17.08%). Impressively, a substantial cumulative capacity of 3500 mAh cm^-2 is attained at 10 mAh cm^-2 and a 56.93% Zn utilization rate. Besides, the enhanced Zn (10 µm) ||I₂ (10.87 mg cm^-2) full cell sustains over 1490 cycles at 1 A g^-1 with 77.13% capacity retention and a harsh N/P ratio of 2.31. Remarkably, the Zn (10 µm) ||I₂ pouch cell achieves over 680 cycles with an ultralow N/P ratio of 2.04.