Electrochemical lithium insertion in Zn3P2 zinc phosphide

Zinc phosphide, Zn3P2, was synthesized as powders using three different preparation routes: ball-milling, followed by annealing and ceramic at high temperature. The mechanism of lithium insertion in these various Zn3P2 powders is shown to be unique and involves two distinct but parallel reversible pathways for a large number of inserted lithium (up to 6): one implies exclusively phosphide phases: Zn3P2, LiZnP, Li4ZnP2 and Li3P. The second one only involves Li–Zn alloys: Zn, LiZn4, LiZn. Structural resemblances of the various involved phases account for the rather good reversibility of the electrochemical mechanism.