A high conductive Na4Fe3(PO4)2(P2O7)@C@Cu cathode for sodium-ion battery

In recent years, sodium-ion batteries have emerged as a compelling alternative to lithium-ion batteries due to their high safety and low cost. However, their commercial application has been constrained by the low capacity and short cycle life of their cathode materials. Anion-type cathode materials offer structural stability, but their inherently low electrical conductivity remains the primary bottleneck. This study focuses on Na 4.5 Fe 3.5 (PO 4 ) 2.5 (P 2 O 7 ) (NFPP) and proposes a synergistic modification strategy to enhance its intrinsic conductivity and electrochemical performance. By introducing copper in a hydrogen atmosphere, Simultaneously achieving Cu 2+ doping and elemental copper composite formation. The conductivity of the modified NFPP-0.30Cu sample was significantly enhanced, demonstrating substantially improved performance: its initial discharge capacity at 0.1C reached 124.13 mAh g −1 , approaching the theoretical capacity and representing a 26.26% increase over NFPP. At 20C high-rate discharge, the initial specific capacity is 84.34 mAh g −1 . After 4000 cycles, the capacity retention rate reaches 93.63%. Even at an ultra-high 100C discharge rate, it maintains a high specific capacity of 69.69 mAh g −1 . This synergistic strategy offers a novel approach for synthesizing electrode materials with high intrinsic conductivity. • Cu 2+ -doped and compounded Na 4.5 Fe 3.2 Cu 0.3( PO 4 ) 2.5 (P 2 O 7 ) was prepared. • Doping and compounding of copper elements improves electron conductivity. • Co-modification increases the electrochemical properties.