Electrochemical Characteristics of Ti–P Composites Prepared by Mechanochemical Synthesis

Titanium phosphide composites with various molar ratios (1:1, 1:2, and 1:4) were synthesized by a mechanochemical method and their potential use as an alternative anode material for Li secondary batteries was investigated. The titanium phosphide composites with molar ratios of 1:1 and 1:2 did not show any electrochemical reactivity with Li, while both the and P in the composite with a molar ratio of 1:4 reacted with Li, yielding a reversible capacity of . Ex situ X-ray diffraction analyses and X-ray absorption spectroscopy showed that the composite transformed into cubic phase without decomposing into Ti and during the initial Li insertion. Subsequent cycling showed a highly reversible insertion/extraction process of Li to/from phase, accompanied by the loss/recovery of the long-range cubic order. The cubic phase showed excellent cycling performance with a large capacity of for when the amount of lithium reacted was suitably controlled.