Nano-crystalline Fe₃V₃O₈ material as an efficient advanced anode for energy storage applications

The sodium-ion battery (SIB) is a rapidly developing electrochemically rechargeable storage device and a direct substitute for Li-ion batteries. Therefore, identifying novel materials for sodium-ion storage applications is important. Efficient electrodes are particularly desirable for enhancing storage performance in battery applications. In this study, we fabricated a novel Fe₃V₃O₈ (FVO) anode material for Na/Li-ion storage using hydrothermal technology for the first time. The electrochemical results indicated that the initial sodiation capacity of the FVO anode is as high as 805 mA h g⁻¹ at 100 mA g⁻¹, and a reversible sodiation capacity of 540 mA h g⁻¹ is maintained over 200 cycles at 500 mA g⁻¹, which is more than 1.8 times the commercial hard carbon of ∼300 mA h g⁻¹. In addition, the oxidation states of the chemical compound and the corresponding sodium reaction mechanism are predicted using X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and in-situ/ex-situ X-ray diffraction (XRD) analysis. Overall, the FVO material exhibited significantly higher electrochemical performance, demonstrating promising suitability for sodium-ion storage.