Thermodynamically engineered V3O7/V6O13 heterojunction enable high-performance aqueous zinc-ion batteries through cooperative dual-phase storage

Abstract

Developing high-performance cathode materials with excellent rate capability and long-term cycling stability remains a critical challenge for aqueous zinc-ion batteries (AZIBs). Herein, we demonstrate a novel strategy for synthesizing V₃O₇/V₆O₁₃ heterojunction through thermodynamically controlled phase transformation. Unlike traditional heterostructure designs that rely on interfacial effects or conductive carbon additives, this work presents a paradigm shift by utilizing the synergistic effects of individual components through a simple hydrothermal method combined with low-temperature heat treatment. The rational design enables in-situ generation of V₆O₁₃ through controlled oxygen vacancy formation in V₃O₇. The unique heterostructure exhibits exceptional electrochemical performance, delivering a high reversible capacity of 278.5 mAh g⁻¹ at 0.1 A g⁻¹ and maintaining 163.5 mAh g⁻¹ at 5 A g⁻¹ over 4000 cycles with 84.8 % retention. Mechanistic investigations, complemented by density functional theory (DFT) calculations which revealed favorable interfacial energetics and charge redistribution, reveal that the superior performance originates from a novel cooperative dual-phase storage mechanism, where the metallic V₆O₁₃ and the formation of reversible H_3.78V₆O₁₃ facilitate the thermodynamically favorable formation of Zn₃V₂O₇(OH)₂·2H₂O through H⁺ consumption. This work provides new insights into designing high-performance cathode materials through thermodynamically controlled phase engineering.