First principles study of Jahn–Teller effects in LixMnPO4

The crystal structure and electronic properties of LixMnPO4 (x=0x=0, 0.5, 1) as cathode material of rechargeable lithium ion batteries, are studied through first principles calculations. Results show that the large volume change from LiMnPO4 to MnPO4 is mainly the result of Jahn–Teller (JT) distortion around Mn3+ ions in MnPO4. The JT effect also plays an important role in Li0.5MnPO4 compound. When the valence states of Mn ion change from bivalent to trivalent, Mn atom loses an electron which is initially localized at the Mn-3d(x2−y2) orbital. The results also show that the band gap of Li0.5MnPO4 is the smallest compared to LiMnPO4 and MnPO4.