A novel NASICON-type NaMnTiZr(PO) cathode material with multivalent redox reaction for high performance sodium-ion batteries.

NaMnZr(PO), a typical manganese-based NASICON-type material, has consistently been at the forefront of research on cathode materials for sodium-ion batteries due to the abundant manganese reserve and high operating voltage. However, the severe Jahn-Teller effect, poor electronic conductivity and kinetic limitation of NaMnZr(PO) impose constraints on its rate capability and cycling performance, thereby hindering its practical application. To address this challenge, a ternary NASICON-type material NaMnTiZr(PO)/C, with a multi-metal synergistic effect, is proposed in this study. The substitution of Ti at Zr site significantly mitigates the Jahn-Teller effect induced by Mn. Furthermore, the stability of the ZrO bond is enhanced, leading to a more robust crystal structure overall. Cyclic voltammetry and constant-current intermittent titration techniques reveal that the appropriate Ti substitution markedly boosts the electronic conductivity and Na diffusion coefficient of the electrode material, thereby mitigating polarization effects and expediting electrode reaction rates. Leveraging the multi-effect of Ti substitution, the prepared NaMnTiZr(PO)/C presents an improved electrochemical performance. Notably, NaMnTiZr(PO)/C enables a high discharge capacity of 71.0 mAh g at 10C and maintains 78.8 % capacity after 1000 cycles at 2C rate. This investigation establishes a robust theoretical foundation for comprehending the synergistic effects of multimetal systems in NASICON materials and offers insights into the development of cost-effective, high-performance cathode materials.