Effect of cycling conditions on the electrochemical performance of high capacity Li and Mn-rich cathodes for Li-ion batteries

Li and Mn-rich layered oxide cathodes although exhibit high specific capacities ≥240 mAh g^-1, suffer from capacity fading and discharge voltage decay during prolonged cycling to potential higher than 4.5 V. This study aimed at exploring an interesting Co-free Li and Mn rich cathode material and to understand how the upper potential applied affects its capacity and average discharge voltage upon prolonged cycling. Li_1.17Ni_0.25Mn_0.58O₂ cathodes were explored in Li cells by galvanostatic charge-discharge cycling in several potential ranges. The specific capacity, capacity retention and average discharge voltage were compared with and without activation to 4.6-4.8 V when cycled to different upper potential limits. This cathode material exhibited a high discharge capacity of 242 mAh g^-1 when cycled in the potential range of 2.3-4.6 V after activation to 4.8 V with gradual capacity fading and average discharge voltage decreasing from 3.62 V to 3.55 V during 100 cycles. When cycled in the potential range of 2.3-4.3 V after activation to 4.6 V, it exhibited a relatively stable capacity >160 mAh g^-1 and stable average discharge voltage of 3.61 V, during 100 cycles. Thus, with optimized operating condition, the Li and Mn-rich cathode material Li_1.17Ni_0.25Mn_0.58O₂ is promising for lithium-ion batteries.