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

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. (C) 2015 Elsevier Ltd. All rights reserved.