Boosting Zinc Electrode Reversibility in Aqueous Electrolytes by Using Low‐Cost Antisolvents

Abstract

Antisolvent addition has been widely studied in crystallization in the pharmaceutical industries by breaking the solvation balance of the original solution. Here we report a similar antisolvent strategy to boost Zn reversibility via regulation of the electrolyte on a molecular level. By adding for example methanol into ZnSO₄ electrolyte, the free water and coordinated water in Zn²⁺ solvation sheath gradually interact with the antisolvent, which minimizes water activity and weakens Zn²⁺ solvation. Concomitantly, dendrite-free Zn deposition occurs via change in the deposition orientation, as evidenced by in situ optical microscopy. Zn reversibility is significantly boosted in antisolvent electrolyte of 50 % methanol by volume (Anti-M-50 %) even under harsh environments of -20 °C and 60 °C. Additionally, the suppressed side reactions and dendrite-free Zn plating/stripping in Anti-M-50 % electrolyte significantly enhance performance of Zn/polyaniline coin and pouch cells. We demonstrate this low-cost strategy can be readily generalized to other solvents, indicating its practical universality. Results will be of immediate interest and benefit to a range of researchers in electrochemistry and energy storage.