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

Abstract

BackgroundLiNi0.8Co0.1Mn0.1O2 (NCM811) has been considered for commercial application of next-generation 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. MethodsLiNi0.8Co0.067Fe0.033Mn0.1O2 (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 findingsFe1-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%).