Preparation and performance comparison of LiMn2O 3.95Br0.05 and LiMn2O3.95Br 0.05/SiO2 cathode materials for lithium-ion battery

摘要

LiMn2O3.95Br0.05 and LiMn 2O3.95Br0.05/SiO2 cathode composites for lithium-ion battery are prepared by solid-state reaction methods. The crystalline structures of the as-synthesized samples are investigated by X-ray diffraction and transmission electron microscope; at the same time, the electrochemical performances are tested by cyclic voltammetry and galvanostatic cycling. The results reveal that the sample of LiMn2O 3.95Br0.05/SiO2 has more excellent electrochemical performance than the sample of LiMn2O 3.95Br0.05. It delivers an initial discharge capacity of 145.3 mAhg-1 at ambient temperature, and 138.9 mAhg-1 at the higher temperature of 55 °C with good capacity retention with the voltage range of 3.0-4.35 V (vs. Li) at a current density of 0.5 C; while the sample of LiMn2O3.95Br0.05 only deliver initial discharge capacity 136.5 mAhg-1 at ambient temperature, and 119.2 mAhg-1 at 55 °C in the same conditions; in addition, the rate performance of LiMn2O3.95Br0.05/SiO2 is excellent too, so the SiO2 layer has improved the electrochemical behaviors of LiMn2O3.95Br0.05 availably.