Design of oxygen vacancies homologous heterojunction promoted reversible zinc ion storage

Zinc ion batteries (ZIBs) are promising for large-scale energy storage applications, but the technology lacks high-capacity and high-stability cathode materials. Herein, oxygen vacancy-VN/V₂O₃/C (Ov-VN/V₂O₃/C) heterostructural composite was successfully designed and synthesized as high-stability cathode to promote reversible ZIBs. Thanks to the oxygen-vacancy heterojunction features and the transformed amorphous new phase V₁₀O₂₄·12H₂O, Ov-VN/V₂O₃/C provides abundant channels and active sites for Zn²⁺ diffusion and adsorption. Thus, Ov-VN/V₂O₃/C as a cathode material for aqueous ZIBs exhibits excellent a high reversible capacity of 531 mAh g⁻¹ at 0.3 A g⁻¹, good rate performance (446 mAh g⁻¹ at a high current density of 10 A g⁻¹), and good stability (115 mAh g⁻¹ at 20 A g⁻¹ after 5000 cycles). More importantly, Ov-VN/V₂O₃/C//Zn assembled quasi-solid-state batteries also have excellent long-term cycling performance. This work not only obtains high-performance cathode materials, but also provides a new idea for the development of the synthesis of transformational new materials with the synergistic effect of vacancies (defects) and heterojunctions.

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