Three-dimensional nanostructured Co₂VO₄-decorated carbon nanotubes for sodium-ion battery anode materials

Since Co₂VO₄ possesses a solid spinel structure and a high degree of stability, it has gained interest as a possible anode material for sodium-ion batteries. However, the application of this electrode material is still hampered by its poor electrical conductivity and severe volume expansion. Uniform Co₂VO₄ nanoparticles (CVO) were grown on carbon nanotubes (CNTs) by a simple solvothermal method to form string-like conductive networks (CVO/CNTs). The flexible and highly conductive three-dimensional (3D) carbon nanotubes and small-sized CVO NPs can enhance the rapid transport of electrons, thereby enhancing the conductivity of the composite. String-like conductive network structures have a larger specific surface area, enhancing electron/ion transmission by fully contacting the electrolyte. The findings demonstrate the superior Na⁺ storing capability of the CVO/CNTs composite. The battery has a great rate performance (148.2 mAh·g⁻¹ at 5 A·g⁻¹) and outstanding long-term cycling performance (147.3 mAh·g⁻¹ after 1000 cycles at 1 A·g⁻¹). In high-rate, long-cycle sodium-ion batteries, CVO/CNTs composites offer a wide range of possible applications. Graphical abstract: [Figure not available: see fulltext.]