Enhanced interfacial charge transport motivated by Bi2Te3–SbPO4@NC heterointerface for superior Zn2+ and NH4+ storage system

Abstract

Aqueous energy storage technologies hold great promise in the renewable energy field. Transition metal dichalcogenides (TMDs) have garnered significant attention as prospective cathode materials. However, their development has been hampered by sluggish ionic transport kinetics and structural instability during repeated ion insertion/extraction processes. Herein, a heterostructured Bi₂Te₃–SbPO₄ composite anchored on nitrogen-doped carbon frameworks (Bi₂Te₃–SbPO₄@NC) is designed to address these challenges. The formation of a built-in electric field at the heterojunction interface, in conjunction with the conductive NC framework, promotes uniform material distribution and effectively mitigates volume expansion during Zn²⁺ and NH₄⁺ intercalation/de-intercalation. Density functional theory (DFT) calculations reveal that the Bi₂Te₃–SbPO₄@NC heterointerface exhibits enhanced adsorption energies for both Zn²⁺ (−1.687 eV) and NH₄⁺ (−2.296 eV) compared to pristine Bi₂Te₃. These synergistic effects collectively contribute to outstanding dual-ion storage capabilities, as evidenced by the high specific capacity of 295 mA h g⁻¹ at 1 A g⁻¹ for zinc-ion storage and 325 mA h g⁻¹ at 0.5 A g⁻¹ for ammonium-ion storage. Remarkably, the hybrid device achieves exceptional long-term cycling stability with 99.1% capacity retention after 9000 cycles for Zn²⁺ and 84.66% retention after 2000 cycles for NH₄⁺. This work provides fundamental insights into heterointerface engineering for developing high-performance dual-ion battery systems.