Achieving Wide-Temperature-Range Sustainable Zinc-Ion Batteries via Magnesium-Doped Cathodes and Gel Electrolytes

Abstract

The continuous growth of electrification of transportation and grid energy storage applications has driven the demand for broadening the temperature range of electrochemical energy storage batteries. Here, we demonstrate a strategy of magnesium-doped VO2 (Mg-VO2) to adjust the charge density of O and enhance the electrochemical performance of cathode materials at low and high temperatures. At the same time, polyacrylamide (PAM) cross-linked with hydroxyethylcellulose (HEC) (PAM-HEC) is used as an electrolyte to further improve the temperature resistance, and the rechargeable zinc-ion battery assembled with it can stably charge and discharge between −20 and 60 °C. Therefore, the obtained rechargeable zinc-ion battery can cycle charge and discharge for more than 650 h at a current density of 100 mA g–1 at both 60 and −20 °C. Advanced characterization and theoretical calculations reveal the special solvation structure of Zn2+ in PAM-HEC, which results in the excellent performance. The carbonyl group on PAM can chelate with Zn2+ to promote its dissociation, and less solvation water can reduce the side reactions at the electrode–electrolyte interface. Our work proposes an effective strategy for the rational design of wide-temperature-range electrode materials and electrolytes, which can achieve all-weather use of the next generation of secondary zinc-ion batteries.