Elevating electrochemical performance of Na4MnCr(PO4)3 cathode material for sodium ion batteries through the synergistic effect of Sc doping and RuO2/C coating

Abstract

The widespread interest in Na4MnCr(PO4)3 (NMCP) for sodium-ion batteries (SIBs) derives from its high energy density and earth abundance. Nevertheless, the poor rate capability and unsatisfactory cycle performance restrict the application of NMCP cathodes in commercialized SIBs. Herein, we designed and prepared the dual-modified NMCP cathode materials by combining doping Sc3+ and hybrid coating with RuO2/C. Benefiting from the synergistic effects of two approaches, the structural stability and the Na+ diffusion as well as the electronic conductivity have been elevated synchronously. Therefore, the optimized Na4MnCr0.95Sc0.05(PO4)3@RuO2/C composite (NMCSP@RC) presents a superior rate capability (163.4 mAh/g at 50 mA g−1 and 87.6 mAh/g at 1000 mA g−1) and extended cycle stability (capacity retention of 66.3 % after 500 cycles at 1000 mA g−1) compared to pure NMCP. Moreover, a full SIB cell with NMCSP@RC cathode demonstrates a praiseworthy energy density of 469.8 Wh kg−1. This study proves the effectiveness of the dual modification strategy on NMCP, which could provide a fresh idea to optimizing the performance for NMCP cathode materials and contribute to the final fulfillment of their commercialized application.