High-voltage performance of concentration-gradient Li[Ni0.6Co0.2Mn0.2]O2 layered oxide cathode materials for lithium batteries

Abstract

High-voltage performance concentration-gradient Li[Ni_0.6Co_0.2Mn_0.2]O₂ (CG-NCM622) layered oxide cathodes consisting of Li[Ni_0.8Co_0.1Mn_0.1]O₂ cores and stable outer layers of Li[Ni_1/3Co_1/3Mn_1/3]O₂ were synthesized via co-precipitation. CG-NCM622 showed structural stability and excellent electrochemical performances compared to Li[Ni_0.8Co_0.1Mn_0.1]O₂. Results of charge and discharge testing illustrate that CG-NCM622 delivered an initial discharge capacity of 195.6 mA h g⁻¹ at 1C in the voltage window of 2.8–4.6 V, with the corresponding capacity retention of 90% after 100 cycles. The cathode based on this material had superior rate capabilities of 167.6 mA h g⁻¹ at 2 C and 153.1 mA h g⁻¹ at 5 C.