Reversible Lithium Uptake by FeP2

The electrochemical reaction of lithium with the metal phosphide is reported. Li uptake in this material was investigated using electrochemical studies combined with X-ray diffraction, X-ray absorption spectroscopy, and magnetic measurements. The uptake of six Li during the first discharge leads to a specific capacity of 1365 mAh/g, and an amorphous phase retaining substantial Fe-P bonding that displays superparamagnetic behavior and an …