Na3V2O2(PO4)2F nanoparticles sandwiched in Ti3C2 MXene nanosheets for sodium-ion batteries

Abstract

Sodium-ion batteries are considered to be an advantageous alternative to lithium batteries because of the scarcity and expensive cost of lithium. To address the limitations of limited capacity and poor rate in sodium-ion batteries, it is necessary to explore advanced cathode materials to develop high-performance sodium batteries. Na₃V₂O₂(PO₄)₂F is a promising sodium cathode material, but its performance has been often restricted by poor conductivity. In this work, we report on the design and synthesis of a porous composite in which Na₃V₂O₂(PO₄)₂F nanoparticles are sandwiched between Ti₃C₂ MXene nanosheets. In this structure, the porous MXene nanosheets facilitate the infiltration of the electrolyte, allowing more paths for sodium ion conduction. At the same time, due to the good conductivity of MXene, the conductivity of Na₃V₂O₂(PO₄)₂F could be effectively improved. As a result, the composite exhibits outstanding performance when used as a sodium cathode, delivering a high capacity of 128 mAh g⁻¹ and excellent rate ability of 103 mAh g⁻¹ at 5C (1C = 130 mA g⁻¹), as well as robust stability up to 2500 cycles.