Low-temperature replacement construction of three-dimensional corrosion-resistant interface for deeply rechargeable Zn metal batteries

Aqueous Zn batteries are promising candidates for grid-scale renewable energy storage. Foil electrodes have been widely investigated and applied as anode materials for aqueous Zn batteries, however, they suffer from limited surface area and severe interfacial issues including metallic dendrites and corrosion side reactions, limiting the depth of discharge (DOD) of the foil electrode materials. Herein, a low-temperature replacement reaction is utilized to in-situ construct a three-dimensional (3D) corrosion-resistant interface for deeply rechargeable Zn foil electrodes. Specifically, the deliberate low-temperature environment controlled the replacement rate between polycrystalline Zn metal and oxalic acid, producing a Zn foil electrode with distinct 3D corrosion-resistant interface (3DCI-Zn), which differed from conventional two-dimensional (2D) protective structure and showed an order of magnitude higher surface area. Consequently, the 3DCI-Zn electrode exhibited dendrite-free and anti-corrosion properties, and achieved stable plating/stripping performance for 1000 ​h at 10 ​mA ​cm⁻² and 10 mAh cm⁻² with a remarkable DOD of 79 ​%. After pairing with a MnO₂ cathode with a high areal capacity of 4.2 mAh cm⁻², the pouch cells delivered 168 ​Wh L⁻¹ and a capacity retention of 89.7 % after 100 cycles with a low negative/positive (N/P) ratio of 3:1.