Iron phosphide (FeP) is regarded as a potential anode for Li/Na-ion batteries due to its high specific capacity. However, the poor electrical conductivity along with a rapid capacity degradation is a barrier for its grid applications. Here, we show that a porous composite nanofiber (NF) with FeP nanoparticles embedded in a conductive carbon matrix can be used as high-performance anodes for Li-ion and Na-ion batteries. The FeP/C composite NFs can be produced by a combination of electrospinning, carbonization, oxidation and phosphidation. As an anode for Li-ion batteries, the composite can exhibit a specific capacity over 1100 mAh g⁻¹, which is 3 times higher than that of commercial graphite anode. Even at a fast charge/discharge rate, it shows stable performance for 1,000 cycles. It is equally important that the FeP/C composite can be used for Na storage with a specific capacity of up to 760 mAh g⁻¹ along with excellent cycle stability, much better than the FeP particles without carbon matrix. These results emphasize the importance of the rational design of FeP/C composites, in which the carbon matrix can not only enhance charge and ion transport but also minimize the structural changes upon cycling.

磷化铁（FeP）由于其高比容量而被认为是Li / Na离子电池的潜在阳极。然而，差的电导率以及快速的容量降低是其电网应用的障碍。在这里，我们表明，具有嵌入导电碳基质中的FeP纳米颗粒的多孔复合纳米纤维（NF）可用作锂离子和钠离子电池的高性能阳极。FeP / C复合NF可以通过电纺，碳化，氧化和磷酸化的组合来生产。作为锂离子电池的负极，复合材料的比容量可超过1100 mAh g ^-1，这是商用石墨阳极的3倍。即使以快速的充电/放电速率，它也可以显示1000次循环的稳定性能。同样重要的是，FeP / C复合材料可用于Na储存，比容量高达760 mAh g ^-1，并且具有出色的循环稳定性，比没有碳基质的FeP颗粒要好得多。这些结果强调了FeP / C复合材料合理设计的重要性，其中碳基体不仅可以增强电荷和离子传输，还可以最大程度地减少循环时的结构变化。