A nanorod FeP@phosphorus-doped carbon composite for high-performance lithium-ion batteries

An iron phosphide (FeP) nanorods and phosphorus-doped carbon (P-C) composite ([email protected]) has been successfully fabricated through a two-step strategy, that is, initial synthesis of Fe2P4O12@P-C precursor by polymerization and carbonization under argon atmosphere, followed by formation of FeP nanorods by reducing the Fe2P4O12 precursor with H2. The [email protected] material shows high specific surface area (255.21 m2 g−1) and the pore size distribution covers a broad range centered at 10 nm, indicating mesoporosity. Due to the synergistic effect of the nanorod structure improving the kinetics of Li+ insertion/extraction and the phosphorus-doped carbon enhancing material conductivity and alleviating volume change of the active material during charge–discharge, [email protected] shows excellent electrochemical performance as an anode in Li-ion batteries for both half- and full cells. For the half-cell, the [email protected] composite delivers a Li-ion storage capacity of 714 mA h g−1 at a current density of 100 mA g−1. After cycling at 2 A g−1 for 800 cycles, a capacity of 625 mA h g−1 is remained. When the current density increases to 5 A g−1, a capacity of 420 mA h g−1 is retained, indicating superior rate capability. For the full cell, a nanorod-FeP||LiMnCoNiO2 battery exhibits stable reversible capacities of 367 mA h g−1 (after 100 cycles) and 326 mA h g−1 (after 300 cycles) at current densities of 200 and 500 mA g−1, respectively. The work described here provides a promising anode material for Li-ion batteries, and the preparation route can be viewed as a reference for the synthesis of transition metal phosphides.