Metal phosphate-coated Ni-rich layered oxide positive electrode materials for Li-ion batteries: improved electrochemical performance and decreased Li residuals content

The growing popularity of Li-ion batteries in the field of energy storage necessitates the constant development of methods for improving their performance. To address this task, this study describes the effect of transition metal (TM = Al, Co, Fe) phosphate coatings on the electrochemical performance of Li1.0Ni0.8Co0.15Mn0.05O2 positive electrode materials, highlighting the importance of the TM/P mole ratio, and reveals that decreased amounts of Li residuals were observed for all coated samples. Considering Li residual removal as well as capacity and capacity retention upon cycling, the most effective surface modification was achieved in the case of a 1:1 Co/P coating, which increased initial capacity and capacity retention by 10 mAh g−1 and 3%, respectively, as compared to the uncoated sample. Moreover, the beneficial effect of the above Co/P coating is also confirmed for the more Ni-rich Li1.0Ni0.91Co0.06Mn0.03O2.