High-voltage performance concentration-gradient Li[Ni0.6Co0.2Mn0.2]O2 (CG-NCM622) layered oxide cathodes consisting of Li[Ni0.8Co0.1Mn0.1]O2 cores and stable outer layers of Li[Ni1/3Co1/3Mn1/3]O2 were synthesized via co-precipitation. CG-NCM622 showed structural stability and excellent electrochemical performances compared to Li[Ni0.8Co0.1Mn0.1]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.
![Graphical abstract: High-voltage performance of concentration-gradient Li[Ni0.6Co0.2Mn0.2]O2 layered oxide cathode materials for lithium batteries](http://hg.y866.cn/compound/lib/scimg/usr/1/C7NJ04936F.jpg)
