The reaction of Fe(N(SiMe3)(2))(3) with PH3 in THF at 100 degrees C gives amorphous FeP2 in high yield. As an anode material in a Li ion battery, this material shows remarkable performance toward electrochemical lithiation/delithation, with gravimetric discharge and charge capacities of 1258 and 766 mA h g(-1), respectively, translating to 61% reversibility on the first cycle and a discharge capacity of 906 mA h g(-1) after 10 cycles. This translates to 66% retention of the theoretical full conversion capacity of FeP2 (1365 mA h g(-1)).