中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 6 June 2024 |
（1. Engineering Laboratory of Battery Safety and Accident Control of Petroleum and Chemical Industry, Changzhou University, Changzhou 213164, China;
2. School of Safety Science and Engineering, Changzhou University, Changzhou 213164, China;
3. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China;
4. Hefei Gotion High-Tech Power Energy Co., Ltd., Hefei 230016, China）
Abstract:To reveal how the performance of LiNixCoyMnzO2 (NCM) changes as a function of transition metal (TM) composition, the effect of TM ratio on the structure, morphology, electrochemical performance and thermal behavior of different NCMs was systematically investigated. Increasing Ni content leads to higher reversible capacity but worse rate capability and cycling stability. Inhibited kinetics of Li+ and poor electronic conductivity cause major capacity loss in Ni-rich NCMs. Comparison of thermal behaviors was carried out via in-situ and ex-situ micro-calorimetry. With the decrease of Ni content, the thermal stability is significantly improved. The oxygen release related to phase transitions was evaluated based on Li residuals in delithiated NCMs, which verifies that Ni-rich materials exhibit severer structural deterioration, lower onset temperature and more heat release. Comprehensive characterization identifies that LiNi0.5Co0.3Mn0.2O2 strikes a well-balanced combination of electrochemical performance and safety features.
Key words: lithium-nickel-cobalt manganese oxide; thermal stability; structural evolution; ternary material; lithium ion battery safety
