Activating Zn2+ adsorption-intercalation-conversion behaviors in Te-doped CuS/Cu2S anode with sulfur vacancy and heterointerface for high capacity and long lifetime

Developing conversion-type CuS anode for constructing rocking-chair zinc-ion batteries (RCZIBs) represents a promising approach to address dendrite growth and self-corrosion in zinc metal batteries. However, the limitations of low capacity and poor cycling stability in practical applications, as well as unclear relationship between intercalation process and conversion reaction, impede its progress. Herein, Te-CuS/Cu₂S-20 anode with sulfur vacancy and heterointerface are proposed through Te-doping induction strategy. Theoretical calculations confirm that heterointerface can adjust d-band center for high Zn²⁺ adsorption and generate built-in electric field for fast charge transfer. Sulfur vacancy can reduce electrostatic interactions for rapid Zn²⁺ diffusion and Te-doping can weaken Cu-S bond for high-efficiency conversion reaction. Furthermore, the Zn²⁺ interfacial adsorption-intercalation-conversion mechanism is revealed, and the enhanced intercalation process can facilitate the subsequent conversion reaction depth. These features endow Te-CuS/Cu₂S-20 with a high capacity (229.5 mAh g⁻¹ at 0.1 A g⁻¹) and an exceptional long-term cycling stability (95.4 % capacity retention after 2000 cycles at 5.0 A g⁻¹). MnO₂//Te-CuS/Cu₂S-20 full battery achieves a distinguished capacity retention (100 % after 5000 cycles at 5.0 A g⁻¹), demonstrating considerable potential in replacing the traditional zinc metal anode. This work provides a novel perspective for developing high-performance conversion-type anode materials in RCZIBs.