Synthesis and electrochemical properties of Th-doped LiMn2O4 powders for lithium-ion batteries

To improve the cycle performance of eco-friendly and cost-effective spinel LiMn2O4 as the Li secondary batteries, the Th-doped LiThxMn1-xO4 spinel powers were synthesized by solid-state method. The starting materials, Li2CO3, MnO2 and Th(NO3)4·4H2O, were mixed uniformly using a traditional ball milling, which resulted in a uniform particle size distribution in the mixed powers. Tests of X-ray diffraction, SEM, impedance spectra and charge-discharge were carried out for LiThxMn1-xO4 cathode materials. Results show that the synthesized LiTh0.01Mn1.99O4 material exhibits standard spinel structure, regular particle morphology and excellent property of charge-discharge for big current. The capacity retention of the material modified by doping Th is more than 85.1% of the first discharge specific capacity of 111.5 mAh·g-1 after 20 cycles at the current rate 1C, while the pristine LiMn2O4 is only 57% of the first discharge specific capacity of 110.2 mAh·g-1 after the same cycles at the same current rate.