Lattice modulation improving surface passivation of LiMnPO4 for stable cycling at high temperatures

Abstract

The undesirable capacity degradation of LiMnPO4 upon cycling at high temperatures is a challenge to its practical application. Herein, a lattice doping strategy is adopted to improve the high-temperature cycling stability of LiMnPO4, and the comparative study reveals that Al3+ doping into LiMnPO4 in a form of Li0.98Al0.02MnPO4 is highly beneficial to the cycling performance of LiMnPO4 and the capacity retention can be significantly improved from 67.4 % to 93.4 % after 100 cycles at 1C at 60 °C, because Al3+ doping can effectively reduce passivation products deposition on the cathode and manganese dissolution in the electrolyte, which thus improve the cathode/electrolyte interface and stabilize the structure of LiMnPO4 at high temperatures.