Improvement of the electrochemical properties of Na2MnPO4F by dual modification of Na3V2(PO4)2F3 and Ti3C2-CQDs

The effects of the two materials, Ti3C2-CQDs and Na3V2(PO4)2F3, on the electrochemical properties of Na2MnPO4F were systematically investigated by double modification of Na2MnPO4F by spray drying method combined with high-temperature calcination. Firstly, different ratios of xNa2MnPO4F-(1-x)Na3V2(PO4)2F3 materials were synthesized and discussed to obtain 0.6Na2MnPO4F-0.4Na3V2(PO4)2F3 material as optimal ratio. Ti3C2-CQDs were added on this basis, and electrochemical tests were performed at the same time. The initial discharge-specific capacity of 0.6Na2MnPO4F-0.4Na3V2(PO4)2F3/Ti3C2-CQDs was 137.4 mAh-g−1, indicating that Ti3C2-CQDs can improve the electronic conductivity as well as the ion diffusion rate of the material and the capacity retention rate. Na3V2(PO4)2F3 can effectively inhibit the Jahn–Teller effect, enhance the stability of the material structure, and improve the electrochemical activity of the material. The synergistic modification leads to a double enhancement of the electrochemical performance of Na2MnPO4F. It hopes that the findings can provide ideas for improving the electrochemical properties of polyionic compounds.