Roughened Graphite Collector Coupled with Hydrolysis-Resistance Zinc Chloride Electrolyte Enables Large-Size Rechargeable Ag–Zn Battery

Ag–Zn batteries have the advantages of being a high-safety and stable discharge platform but still face challenges such as high cost, electrolyte hydrolysis, and zinc dendrites. In this study, a low-cost roughness graphite paper (GP) enables more uniform loaded Ag particles to construct Ag/rough graphite paper (Ag/RGP) cathode with high wettability of low-concentration ZnCl₂ electrolyte, achieving both capacity and reversibility enhancement. Both a few additions of citric acid (CA) to the low-concentration ZnCl₂ electrolyte can also inhibit the hydrolysis of Zn²⁺ and increase the nucleation overpotential due to suitable acidity and complexation ability, resulting in more even Zn deposited behavior on low-cost Zn foil anode. Meanwhile, the ZnCl₂-CA electrolyte can also promote redox reaction and thus improve the capacity of the Ag/RGP cathode. As a result, the assembled large-size Ag–Zn battery (50 cm²) with low-cost Ag/RGP and low-concentration ZnCl₂-CA obtains a capacity of 0.76 mAh cm⁻² at a current density of 0.4 mA cm⁻², with a cycle life of ≈100% capacity retention over 50 cycles, also easily powering a LED array and displaying high practicability. This work provides a feasible and practical route to fabricate large-size and low-cost Ag–Zn batteries.