Synthesis and electrochemical properties of Th-doped LiMn 2O 4 powders for lithium-ion batteries

Abstract

To improve the cycle performance of eco-friendly and cost-effective spinel LiMn 2O 4 as the La secondary batteries, the Th-doped LiTh x Mn 1 − x O 4 spinel powers were synthesized by solid-state method. The starting materials, Li 2CO 3, MnO 2 and Th(NO 3) 4·4H 2O, 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 LiTh x Mn 1− x O 4 cathode materials. Results show that the synthesized LiTh 0.01Mn 1.99O 4 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 LiMn 2O 4 is only 57% of the first discharge specific capacity of 110.2 mAh·g −1 after the same cycles at the same current rate.