Charge/discharge behavior of triclinic litiopo4 anode materials for lithium secondary batteries

Abstract

Triclinic LiTiOPO4 fine powders were synthesized via low-Temperature thermal treatment. First, amorphous fin powders were prepared by mechanical milling (MM) treatment of a mixture of the starting materials (Li2CO3, TiO2 and P2O5) at room temperature. The mechanically milled amorphous powder formed a triclinic LiTiOPO4 crysta below 700°C in air. The mechanically milled powders before heat treatment barely worked as an active material a ca. 0.1C rate in the potential range of 1.0 to 3.0V versus Li/Li+ in lithium cells. On the other hand, the triclini LiTiOPO4 compounds obtained by the crystallization of the mechanically milled amorphous powders at 700©C i air worked as anode materials in lithium cells. The triclinic LiTiOPO4 electrode materials exhibited capacities o around 100mAhg?1. The average operation potential was around 1.7V (vs. Li/Li+). The triclinic LiTiOPO4 pristin compound when used as an anode caused a phase transition into an orthorhombic compound during lithiu insertion (charge process). The orthorhombic compound changed into a triclinic phase during lithium extractio (discharge process). The triclinic LiTiOPO4 electrodes exhibited a good cycle performance in the potential range o hase changes reversibly during charge/discharge.