Boosting Zn metal anode stability with a dimethylformamide additive

Abstract

Aqueous zinc-ion batteries (ZIBs) hold great promise in electrochemical applications due to their cost-effectiveness and high safety. However, the practical utilization of ZIBs faces challenges from detrimental zinc dendrite formation and side reactions, which adversely impact their cycling lifespan and electrochemical stability. In this research, we proposed a commonly available and cost-effective organic solvent, N, N-dimethylformamide (DMF), as an electrolyte additive to stabilize Zn anode. According to the experimental characterizations and theoretical calculations, DMF exhibits a strong interaction with Zn2+ ions, which can not only regulate the Zn2+ solvation structure to mitigate side reactions, but also promote the uniform deposition of Zn2+ to suppress Zn dendrites. Hence, the symmetrical Zn/Zn cell assembled with a mixed electrolyte of ZnSO4 and DMF (ZSO+DMF) demonstrated an impressive cycle lifespan of up to 1600 h under a current density of 1 mA cm−2. Moreover, the coulombic efficiency (CE) of Zn/Ti batteries operating at 1 mA cm−2 was significantly improved to 98.36%, surpassing that in ZnSO4 electrolytes (95.34%). Additionally, the performance of Zn/VO2 cells further validates the effectiveness of the DMF additive. These findings highlight the potential of DMF as a valuable electrolyte additive to enhance the electrochemical performance and cycling stability of Zn-based batteries, offering a practical and cost-efficient approach to advancing the development of ZIBs.