Rapid Synthesis of Honeycomb-Structured FeP2@NHC for High-Rate and Durable Lithium Storage

The concurrent preservation of structural integrity and improvement of electrical conductivity in FeP2anodes presents a persistent challenge. Herein, FeP2nanoparticles embedded within a 3D N-doped honeycomb-like carbon framework composite (FeP2@NHC) are synthesized through a phosphorization process with a honeycomb-like Fe3C@NHC as a precursor. The in situ incorporation of FeP2nanoparticles into the 3D carbon matrix effectively restrains the aggregation, pulverization, and stripping of material during cycling, and significantly enhances reaction kinetics and structural stability, achieving a superior electrochemical performance. Specifically, FeP2@NHC electrodes demonstrate remarkable reversible capacity (1433.9 mA h g−1at 0.1 A g−1), excellent rate-capability (399.9 mA h g−1at 10 A g−1), and ultra-long cycle life (631.5 mA h g−1after 1000 cycles at 2 A g−1). Moreover, XRD analysis reveals that iron-rich Fe3C and Fe3O4precursors can react with NaH2PO2to form FeP2and FeP, respectively. This study offers a rational and practical strategy for designing other phosphorus-rich metal phosphide anode materials.