NMC622, with a chemical formula of LiNi0.6Mn0.2Co0.2O2, is named after the composition ratio of nickel, manganese and cobalt as 6:2:2. Being a mid-nickel cathode material, this it displays greater capacity extracted at the same potential and improved stability, compared to low-nickel NMC cathode materials.
Further modification with an ultra-thin CeO2 coating overcomes the H2/H3 phase transition, reducing Ni/Li mixing and leading to a long battery life. At the end of the 50th cycle test, ceria-coated NMC622 gains 14% capacity while pristine NCM622 loses 18% of its initial capacity. This behaviour indicates activation for efficient Li diffusion, mediated by the enhanced electronic interaction between ceria and NMC.
It has also demonstrated good oxygen evolution reaction activity in 1 M KOH solution. It shows an overpotential of 280 mV to pass 100 mA·cm−2 and a low Tafel slope of 42 mV·dec−1.