Preformation of Zn based layered double hydroxides on Zn powder solvent-free electrode for low temperature soft-package Zn-MnO2 battery

Abstract

Zinc-ion batteries, leveraging aqueous electrolytes for inherent safety, offer promising development prospects due to their lower costs and high specific capacities compared to lithium-ion batteries that use organic electrolytes. However, aqueous zinc-ion batteries exhibit unsatisfactory discharge capacity and power density under low-temperature conditions, and sometimes even fail to operate normally, severely restricting the practicality of rechargeable zinc-ion batteries. Therefore, based on the zinc powder solvent-free electrode system, this paper proposes a method of adding methanol low-temperature additives after in situ pre-constructing Zn(OTf)₂ basic layered double hydroxides (LDHs) on the anode-electrolyte interface (SEI) of the anode surface. This method not only prevents the exposed zinc anode from directly reacting with methanol to cause corrosion, but also adjusts the solvation structure to inhibit the formation of zinc dendrites, enabling Zn to deposit uniformly without easily forming dendrites. The results show that the Zn||MnO₂ soft-packed battery has good cycle stability, reversibility, and excellent antifreeze performance under low-temperature conditions of −25 °C. This method is also applicable to the 1.2 Ah Zn||MnO₂ pouch-type full battery with high MnO₂ areal loadings of 15 mg cm⁻². This work provides a new strategy for achieving excellent performance of aqueous zinc-ion soft-packed batteries under low-temperature conditions.