Stabilizing electrolytic Zn||MnO2 batteries under lean electrolyte conditions via synergistic anode and electrolyte engineering

Electrolytic Zn||MnO₂ batteries utilizing acidic electrolytes are promising for large-scale energy storage owing to their high energy/power densities. However, they encounter challenges such as hydrogen evolution corrosion on Zn anodes and excessive electrolyte-to-cathode capacity ratios (E/C ratio > 0.05 mL mAh⁻¹). Here, we introduce a synergistic approach combining a zeolitic imidazolate frameworks (ZIFs)-coated Zn anode and acetic acid (HOAc)-modified electrolyte to stabilize electrolytic Zn||MnO₂ batteries under lean electrolyte conditions. Specifically, HOAc substitutes partial imidazole ligands within the ZIFs coating, forming a dense, acid-resistant amorphous ZIFs (aZIFs) layer that effectively mitigates Zn anode corrosion. Simultaneously, the HOAc-modified electrolyte acts as a proton reservoir for the MnO₂ cathode, enabling reversible MnO₂/Mn²⁺ redox chemistry. This dual modification allows the ZIFs@Zn||MnO₂ coin cell to retain 80.4 % capacity after 1000 cycles at 5.0 A g^–1 and the pouch cell to achieve an output voltage exceeding 1.5 V at 0.5 A g⁻¹ with a E/C ratio of 0.018 mL mAh⁻¹. Our work provides a feasible approach to develop practical electrolytic Zn||MnO₂ batteries.