Electrochemical performance of SrF2-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for Li-ion batteries

✍ Scribed by Jiangang Li; Li Wang; Qian Zhang; Xiangming He

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 894 KB
• Volume: 190
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2008.08.011

✦ Synopsis

SrF 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode materials with improved cycling performance over 2.5-4.6 V were investigated. The structural and electrochemical properties of the materials were studied using Xray diffraction (XRD), scanning electron microscope (SEM), charge-discharge tests and electrochemical impedance spectra (EIS). The results showed that the crystalline SrF 2 with about 10-50 nm particle size is uniformly coated on the surface of LiNi 1/3 Co 1/3 Mn 1/3 O 2 particles. As the coating amount increased from 0.0 to 2.0 mol%, the initial capacity and rate capability of the coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 decreased slightly owing to the increase of the charge-transfer resistance; however, the cycling stability was improved by suppressing the increase of the resistance during cycling. 4.0 mol% SrF 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 showed remarkable decrease of the initial capacity. 2.0 mol% coated sample exhibited the best electrochemical performance. It presented an initial discharge capacity of 165.7 mAh g -1 , and a capacity retention of 86.9% after 50 cycles at 4.6 V cut-off cycling.