Preparation and Properties of Al₂O₃-doping LiNi_1/3Co_1/3Mn_1/3O₂ Cathode Materials

Abstract

LiNi_1/3Co_1/3-xMn_1/3O₂ doped with Al₂O₃ (x = 0%, 2.5%, 5%, 10%) was synthesized by co-precipitation of Ni, Co, and Mn acetates. The influence of Al₂O₃ doping on structure and electrochemical performances of LiNi_1/3Co_1/3Mn_1/3O₂ was studied using X-ray diffraction (XRD) analysis, scanning electron microscopy, charge/discharge tester, and electrochemical workstation. It was found that the materials achieved the best electrochemical properties when x was 5%. The first discharge capacity was 156.3 mAh · g⁻¹(0.1 C, 2.0–4.8 V), which was close to the un-doped sample (156.8 mAh · g⁻¹). After 20 cycles, the capacity retention ratios at the C-ratios of 0.1C, 0.2C, and 0.5 C were 96.1%, 94.9%, and 89.4%, respectively, while the capacity retention ratios of the un-doped samples were only 92.6% (0.1 C), 91.8% (0.2 C), and 88.7% (0.5C). The alternating current impedance shows that the charge transfer in the electrode interface was the easiest when x was 5%.

Keywords:

• Al₂O₃ doping
• Co-precipitation
• LiNi_1/3Co_1/3Mn_1/3O₂
• Materials
• Properties