NaFe(PO)PO (NFPP) cathodes have received significant attention due to the promising theoretical capacity, high average working voltage, and low volume change, but usually suffer from poor rate performance and cycling stability due to their inferior electronic conductivity. Herein, we report a new high-entropy NaFe(NiCrMgCoMn)(PO)PO (NFPPHE) as outstanding cathode materials for sodium-ion batteries, by which Fe-defects are generated and electronic & ionic transport kinetics are enhanced. The as assembled NFPPHE//Na half-cell demonstrates an excellent rate performance of 57 mAh/g at 100C and a high-capacity retention of 80 % after 4000 cycles at 20C. In addition, the full cell assembled with hard carbon anode displays an energy density of 165 Wh/kg with 76 % capacity retention after 300 cycles at 0.5C. These results demonstrate the feasibility of Fe-defect strategy to enhance the electrochemical performance of cathode material for sodium-ion batteries.

中文翻译：

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高倍率钠离子电池用高熵Na4Fe2.65(NiCrMgCoMn)0.027(PO4)2P2O7正极


NaFe(PO)PO (NFPP)正极由于具有良好的理论容量、高平均工作电压和低体积变化而受到广泛关注，但由于电子电导率较差，倍率性能和循环稳定性通常较差。在此，我们报道了一种新型高熵NaFe(NiCrMgCoMn)(PO)PO (NFPPHE)作为钠离子电池的出色正极材料，通过它产生Fe缺陷并增强电子和离子传输动力学。组装好的 NFPPHE//Na 半电池在 100C 下表现出 57 mAh/g 的优异倍率性能，在 20C 下循环 4000 次后仍具有 80% 的高容量保持率。此外，采用硬碳阳极组装的全电池的能量密度为165 Wh/kg，在0.5C下循环300次后容量保持率为76%。这些结果证明了铁缺陷策略提高钠离子电池正极材料电化学性能的可行性。