Increased cycling stability of AlPO4-coated LiMn2O4 for lithium ion batteries

AlPO4 was used to the surface modification of LiMn2O4 by chemical deposition method to improve the cycling stability of LiMn2O4 at ambient and elevated temperature. The uncoated and AlPO4-coated LiMn2O4 materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and electrochemical test. While the uncoated LiMn2O4 showed 17.9% and 32.9% capacity loss in 50 cycles at 30 °C and 55 °C, respectively, the AlPO4-coated LiMn2O4 only exhibited the capacity loss of 2.6% and 7.6% at 30 °C and 55 °C, respectively. The dQ/dV versus potential plots at 55 °C revealed that the improvement in cycling performance of the coated-LiMn2O4 electrode is attributed to the stabilization of the spinel structure by the presence of AlPO4 on the surface of LiMn2O4.