Reducing Ni/Li disorder and boosting electrochemical performance of LiNi0.8Co0.067Fe0.033Mn0.1O2 cathode material

Background: LiNi0.8Co0.1Mn0.1O2 (NCM811) has been considered for commercial application of nextgeneration lithium batteries due to their high-energy-density. However, Ni/Li disorder affects electrochemical performance, and this restricted further promotion and commercial application of this material. Expensive and toxic Co can boost the reversible properties of electrode materials and decrease Ni/Li disorder. Fe3+ and Co3+ have the same electronic configuration and are considered to replace part of the Co to play the same role. Methods: LiNi0.8Co0.067Fe0.033Mn0.1O2 (Fe1-NCM811) electrode material replacing partly Co with Fe is produced via urea hydrothermal and high temperature sintered process. And NCM811 electrode material is produced by same method. The XRD of NCM811 and Fe1-NCM811 electrode materials were refined by using Maud software. Significant findings: Fe1-NCM811 cathode with Fe replacing part Co obviously reduces Ni/Li disorder degree from 3.58% to 1.16%. The first discharge capacity of Fe1-NCM811 electrode (211.4 mAh g-1) is more than NCM811 electrode (200.8 mAh g-1) at 0.1C, and its rate capacity (142.3 mAh g-1) is more than NCM811 electrode(129.4 mAh g-1) at 5C. The discharge capacity retention rate of Fe1-NCM811 cathode (77.5%) after 500 cycles is nearly three times that of NCM811 cathode (26.1%).

Automated summary

By partially replacing Co with Fe to prepare Fe1-NCM811 electrode material, the degree of Ni/Li disorder can be significantly reduced, and it exhibits higher discharge capacity, rate capacity, and cycle stability compared to NCM811 cathode.