Conversion-Type Nonmetal Elemental Tellurium Anode with High Utilization for Mild/Alkaline Zinc Batteries

Abstract

Zinc ion batteries (ZIBs), generally established on an excessive metallic Zn anode and aqueous electrolytes, suffer from severe dendrites and gassing issues at Zn side, resulting in poor cycling life. Substituting Zn metal anode with non-Zn ones is a promising strategy for solving these problems, whereas this is still restricted by the limited anode alternatives. Herein, by replacing metal Zn with chalcogen element tellurium (Te), a conversion-type Te-based ZIB is reported that can work in both mild and alkaline electrolytes. As expected, the as-assembled mild Te/MnO<inf>2</inf> and alkaline Te/Ni(OH)<inf>2</inf> cells deliver remarkable capacities up to 106 and 161 mAh g⁻¹<inf>anode+cathode</inf>, respectively, with a high utilization of anode (50.1% for the Te/MnO<inf>2</inf> and 38.9% for the Te/Ni(OH)<inf>2</inf>), which surpass all ZIBs. Ultralong cycling life (over 75% capacity retention after 5000 cycles) is achieved in the two systems, benefiting from the stable conversion mechanisms (mild: Te to ZnTe<inf>2</inf> to ZnTe; alkaline: ZnTe to Te to TeO<inf>2</inf>) with thoroughly eliminated dendrites and gassing. Moreover, high gravimetric energy density of ZIBs is also achieved, which are 176.3 Wh kg⁻¹<inf>anode+cathdoe</inf> (Te/Ni(OH)<inf>2</inf>) and 81 Wh Kg⁻¹<inf>anode+cathode</inf> (Te/MnO<inf>2</inf>), respectively. This work sheds light on the development of advanced conversion-type anode for high-performance batteries with superior stability.