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

Abstract 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.