Electrochemical performance of the Li-rich layered Li1.2Mn0.54Ni0.13Co0.13O2 cathode material influenced by Fe3+ doping

Abstract

The extensive application of the layered Li-rich Mn-based cathode material is limited due to the inferior cycling stability, rate capability and voltage decay. The electrochemical performance of Fe 3+ doping Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode material synthesized by sol-gel method was investigated in this paper. It is indicated that Fe 3+ doping Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode material shows excellent electrochemical performance at high current intensity rates, especially the cycling stability and capacity retention. The cathode Li 1.2 Mn 0.54 Ni 0.13 Co 0.12 Fe 0.01 O 2 exhibits excellent initial discharge capacities of 193.5 mAh g −1 at 1 C, 179.8 mAh g −1 at 2 C and 119.6 mAh g −1 at 5 C, and expresses remarkable capacity retention of 87.1% at 1 C and 84.0% at 2 C after 100 charge/discharge cycles, respectively. It is attributed to the beneficial effects of the Fe 3+ doping in the cathode material, which enlarges the lithium layer spacing, decreases charge-transfer resistance and accelerates the Li + diffusion, significantly slows down the decomposition of Li 2 MnO 3 , and efficiently alleviates the irreversible loss of lattice oxygen and the Mn dissolution during cycling. ● Fe 3+ doping maintains well layered structure and phase stability. ● Fe 3+ doping enhances cycling stability and rate capability. ● Fe 3+ doping inhibits the decomposition of Li 2 MnO 3 and loss of lattice oxygen. ● Fe 3+ doping enlarges layer spacing and improves the Li + diffusion coefficient.