Experimental research of electrolyte additives and battery performance of aqueous zinc-ion batteries

Abstract

Abstract Aqueous zinc-ion batteries (AZBs) have received increasing attention due to their high safety, high theoretical specific capacity, and abundant resources. However, the problems of zinc anode dendrite growth, hydrogen precipitation corrosion, and irreversible side reactions in AZIBs have restricted their application process. Electrolyte additives are an effective way to solve problems. This work looked at what would happen when 4-(2-hydroxyethyl) piperazine-1-ethane sulfonic acid (HEPES) was added to the ZnSO4 solution, which is the electrolyte. It was tested on AZIBs by using coin batteries as the carriers and adding HEPES to the electrolyte. The findings demonstrated that the electrolyte exhibited robust stability following HEPES addition, effectively suppressing dendrite growth through electric field modulation at the zinc anode. Incorporating 8 mM HEPES notably enhanced battery cycle longevity to over 240 hours under conditions of 0.2 mA cm−2 and 0.2 mAh cm−2. The HEPES additive was found to be effective in improving the rate capability through the testing of Zn||Zn symmetric batteries. This work provides a feasible idea for the performance improvement of low-cost and high-efficiency AZIBs.