Synthesis of magnesium vanadate-sodium vanadate composite nanowires by cation exchange as electrode materials for lithium ion batteries

In order to meet the requirements for better and more diversified performance of lithium-ion batteries, electrode materials for improving battery performance were studied. Among many electrode materials, vanadium-based materials are suitable for lithium-ion battery electrode materials due to their rich valence changes and various types. Magnesium vanadate (MgV₂O₆)-sodium vanadate (NaV₆O₁₅) composites on titanium foil were synthesized by ion exchange method using sodium vanadate nanowar arrays as precursors. After calcination in air, the temperature was 300℃ and 500℃, respectively. With the increase of the calcination temperature, the diameter of the nanowires became larger. The crystal structure, chemical composition and microstructure of the prepared samples were characterized in detail. Among them, the magnesium vanadate and sodium vanadate composite prepared by calcination at 300℃ had better electrochemical lithium storage performance. The first discharge capacity was 1144 mA·h·g⁻¹ at the current density of 50 mA·g⁻¹, and the specific discharge capacity was still 837 mA·h·g⁻¹ after 100 cycles, showing good cycling stability. Compared with sodium vanadate precursor, the lithium storage performance was significantly improved. It provides a new idea for the application of alkaline earth vanadate synthesized by magnesium ions in the field of electrochemical energy storage.