Honeycomb-like 3D carbon skeletons with embedded phosphorus-rich phosphide nanoparticles as advanced anodes for lithium-ion batteries.

Phosphorus-rich iron phosphides (FeP 2 ) have been regarded as excellent anode candidates for lithium storage owing to their low cost, high natural abundance, high theoretical capacity, and reasonable redox potential. However, FeP 2 suffers from a few challenging problems such as low reversibility, fast capacity degradation, and big volume variation. Herein, we have designed and synthesized a 3D honeycomb-like carbon skeleton with embedded FeP 2 nanoparticles (denoted as FeP 2 NPs@CK), which can significantly promote the kinetics and maintain the structural stability during the cycling, resulting in an excellent electrochemical performance reflected by high reversibility and long-term cycling stability. FeP 2 NPs@CK shows high reversibility, delivering a reversible capacity as high as 938 mA h g -1 at 0.5 A g -1 . It also shows excellent cycling stability, delivering a capacity of 620 mA h g -1 after 500 cycles at 1 A g -1 . Moreover, the fast kinetics and lithium storage mechanism of FeP 2 NPs@CK are investigated by quantitative analysis and in situ X-ray diffraction. Such superior performance demonstrates that FeP 2 NPs@CK could be a promising and attractive anode candidate for lithium storage.