Exploiting bifunctional ZnTe for Zn anode protection and conversion-type cathode toward compatible aqueous Zn-ion batteries

Aqueous zinc-ion batteries (AZIBs) offer an attractive solution for grid-scale energy storage but suffer from a significant challenge in finding advanced Zn anodes and cathodes that are mutually compatible. Here we propose tellurides, specifically ZnTe, as a multifunctional material that can simultaneously serve as a Zn anode protective layer and a cathode material with excellent compatibility and performance. Theoretical analyses disclose that ZnTe possesses high electronic conductivity, favorable Zn2+ adsorption and diffusion, and structural stability upon Zn2+ insertion, which are fundamental to Zn anode protection and Zn2+ storage. Experimental findings reveal that ZnTe effectively protects Zn anodes from dendrite growth and surface corrosion, resulting in a minimal voltage hysteresis of only 38 mV over 3100 h at 1 mA cm–2. Additionally, the ZnTe cathode exhibits a conversion-reaction mechanism of ZnTe ⇄ ZnTe2 ⇄ Te, with excellent plateau capacities. We also demonstrate the good compatibility between ZnTe-based anodes and cathodes by assembling full cells that deliver exceptional cyclability (80 % capacity retention at 2 A g–1 over 1000 cycles). Our work provides a general design guideline for compatible and advanced electrode materials for AZIBs.