Electrochemical Performance of Iron Diphosphide/Carbon Tube Nanohybrids in Lithium-ion Batteries

Graphical abstract: Display Omitted -- Highlights: • Dehydrogenated FeP₂/C nanohybrids were fabricated via a facile annealing process. • The nanohybrids as anode in LIB show excellent cycling stability and rate capability. • C-hybrid promotes buffering volume change and increasing electroconductibility. • The process can be applied for the fabrication of many more TMPs and nanohybrids. -- Abstract: Phosphorous-rich phase iron diphosphide/carbon tube (FeP₂/C) nanohybrids, which are synthesized via a pyrolysis process and composed of heterostructures of orthorhombic FeP₂ with conical carbon tubes, have been identified as a new anode in lithium-ion batteries. After an annealing treatment to eliminate the excessive hydrogen elements in the carbon tubes, the FeP₂/C nanohybrids display good reversible capacity, long cycle life, and excellent rate capability. Specifically, the annealed hybrids exhibit a discharge capacity of 602 mA h g⁻¹ on the second cycle and a discharge capacity of 435 mA h g⁻¹ after 100 cycles at 0.1C (0.137 A g⁻¹). Meanwhile, these annealed hybrids exhibit excellent rate capability, such as a reversible capability of 510 mA h g⁻¹, 440 mA h g⁻¹, 380 mA h g⁻¹, 330 mA h g⁻¹ and 240 mA h g⁻¹ at 0.25C, 0.5C, 1C, 2.5C and 5C, respectively