High-entropy doping NASICON[sbnd]Cathode breaks the kinetic barriers and suppresses voltage hysteresis for sodium ion batteries

Abstract

The NASICON-type Na3MnTi(PO4)3 material has garnered widespread attention for its stable three-dimensional structure, rapid sodium-ion transport channels and excellent thermal stability. However, its poor electronic conductivity, cyclic stability and structural decay during cycling have posed significant obstacles to its commercialization. Herein, a high-entropy doping Na3.12MnTi0.9(VFeMgCrZr)0.02(PO4)3 cathode was successfully synthesized, exhibiting a high reversible capacity of 169.6 mAh g-1 and a high energy density of over 500 Wh kg-1. The DFT and machine learning MD results show that benefiting from the high-entropy effect of multi-element synergy in HE-NMTP, the electronic conductivity and sodium ion diffusion kinetics are significantly improved. Simultaneously, the voltage hysteresis and energy loss are mitigated, while crystal structural stability is improved. Furthermore, the full-cell achieves an impressive energy density of 440 Wh kg-1 (for cathode) at 0.2C. These results demonstrate the advantages of the high-entropy doping cathode as a potential cathode material for sodium-ion batteries and provide a valuable strategy for other NASICON system cathodes as well as polyanion cathodes.