Halide-mediated Ag–Zn batteries in alkaline electrolytes†

The incorporation of bromide ions (Br⁻) as electrolyte additives fundamentally alters the reaction mechanism of alkaline Ag–Zn batteries, effectively suppressing the shuttle effect and mitigating cathode dissolution. Furthermore, a self-supporting polymer-based silver cathode has been engineered to accommodate volume changes during cycling, thereby minimizing capacity degradation. As a result, a halide-mediated Ag–Zn battery demonstrates exceptional cycling stability over 370 cycles, delivering a high Coulombic efficiency exceeding 99.3% with excellent capacity retention. Notably, the system achieves a high areal capacity of 2.3 mA h cm⁻², highlighting its potential for practical application in high-performance rechargeable batteries.