As the anodes for lithium-ion batteries, the conversion-type metal phosphides (M-P) have attracted growing attention based on the formation of Li₃P (2596 mAh g⁻¹). Compared with sulfides and oxides, the M-P systems can react with Li⁺ over the lowest and narrowest potential range. Different from the previously reported wet chemical route, a facile two-step method is used in this study to prepare the novel core-shell FeP₂@C nanomaterials, i.e., fabricating Fe@C nanoparticles by direct current arc plasma followed by phosphorization into FeP₂@C. The experimental results show that the discharge/charge capacity of FeP₂@C (21.16 wt.%, carbon content) increases from 1132 to 1827 mAh g⁻¹ after 500 cycles at 0.3 A g⁻¹. It is because the pulverized FeP₂ nanoparticles provide a more reactive interface for the electrochemical reaction, thus shortening the Li-ion transportation path during cycles. Moreover, FeP₂ is observed to experience the progressive lithiation process, i.e., the lithium ions are gradually inserted into the lattice of FeP₂ to form Li_nFeP₂ and then transformed to Li₃P and Fe. This process is verified in this study by cyclic voltammetry and the first-principles calculations.

作为锂离子电池的负极，基于Li ₃ P（2596mAh g ^-1）的形成，转化型金属磷化物（MP）已引起越来越多的关注。与硫化物和氧化物相比，MP系统可在最低和最窄的电位范围内与Li ⁺反应。与先前报道的湿化学路线不同，本研究使用一种简便的两步法制备新颖的核壳型FeP ₂ @C纳米材料，即通过直流电弧等离子体然后将其磷化为FeP来制备Fe @ C纳米颗粒。₂ @C。实验结果表明，FeP ₂ @C的放电/充电容量（21.16 wt。％，碳含量）从1132 mAh增加到1827 mAh g^-1 0.3 A G 500次循环后^-1。这是因为粉碎的FeP ₂纳米颗粒为电化学反应提供了更多的反应性界面，从而缩短了循环过程中的锂离子传输路径。此外，观察到FeP ₂经历了渐进的锂化过程，即，锂离子逐渐插入FeP ₂的晶格中形成Li _n FeP ₂，然后转化为Li ₃ P和Fe。本研究通过循环伏安法和第一性原理计算验证了这一过程。