Simple synthesis and electrochemical performance of NaVSi₂O₆ as a new sodium-ion cathode material

Developing new sodium-ion battery (SIB) cathode materials with low cost and high capacity remains a challenge. Here, NaVSi₂O₆ was successfully synthesized by a simple sol-gel method for the first time. This material was used as a new SIB cathode material. At a current density of 20 mA g⁻¹, the first discharge specific capacity is 80 mA h g⁻¹, which exhibits a higher capacity. The mechanism of the cycle stability of NaVSi₂O₆ was elucidated by the theoretical calculations. The volume and formation energy change of different content of Na⁺ insertion/extraction, as well as the energy band and density of states were calculated combined with the density functional theory (DFT). Our research results provide a reference for further exploring the NaMSi₂O₆ (M = Fe, Cr, and V) compounds as cathode materials of SIB.