In this work, we for the first time investigate GeP5 as an anode material for lithium ion batteries (LIBs). Using a facile high energy mechanical ball milling (HEMM) method, we successfully synthesize pure GeP5 and GeP5/C nanocomposite at ambient temperature and pressure. According to XRD Rietveld refinement and first principle calculations, GeP5 possesses a two-dimensional layered structure similar to that of black P and graphite, and a high conductivity that is 10000 and 10 times that of black P and graphite, respectively. Serving as novel anode materials, both GeP5 and its carbon composite deliver an unprecedented high reversible capacity of ca. 2300 mA h g−1, combined with a high initial coulombic efficiency of ca. 95%. Ex situ XRD and CV tests demonstrate that GeP5 undergoes conversion and alloying type lithium storage mechanism and that its capacity is co-contributed to by both the Ge and P components. In addition, GeP5/C exhibits superior cycle stability and excellent high-rate performance with a capacity of 2127 mA h g−1 at 5 A g−1. These properties suggest the promising application of these anode materials in next-generation high-energy and high-power LIBs.
