High performance layered LiNi0.8Co0.07Fe0.03Mn0.1O2 cathode materials for Li-ion battery

Ni/Li disordering often occurs in LiNixCoyMn1−x−yO2 (NMC) layered materials and affects the electrochemical performance of Li-ion batteries (LIBs). Substituting partly Co with Fe in the Ni-rich cathode LiNi0.8Co0.10Mn0.1O2 (NCM811) provided a new cathode material (LiNi0.8Co0.07Fe0.03Mn0.1O2 (Fe3-NCM871)) with markedly enhanced electrochemical performance via a coprecipitation method. The Fe3-NCM871 cathode achieved an initial capacity of 207.5 mAh g−1, while the NCM811 cathode has 188.7 mAh g−1 between 2.8 and 4.3 V at the C/10 rate. Its rate capacity (145.8 mAh g−1), 25.7 mAh g−1 higher than the NCM811 at a rate of 5C. Furthermore, it maintains better cycle stability performance and reaches 80% state-of-health (SOH) only after 400 cycles, which is higher than that of the NCM811 (nearly 200 cycles) at C/2 between 2.8 and 4.3 V. As confirmed from density functional theory (DFT) calculations, such high performance is due to linear Ni2+–O2−–Fe3+ superexchange between layers because of the antisite Ni2+ is weak, thus the content of Ni/Li exchange is effectively reduced, which was consistent with the experimental findings.