Electrochimica Acta, Vol.77, 250-255, 2012
The multi-substituted LiNi0.475Al0.01Cr0.04Mn1.475O3.95F0.05 cathode material with excellent rate capability and cycle life
The novel multi-substituted LiNi0.475Al0.01Cr0.04Mn1.475O3.95F0.05 cathode material is synthesized via a sol-gel method. The results show that this material has a well-defined cubic spinel structure, Fd3m space group. The excellent rate capability can be obtained from this material to deliver a discharge capacity of 136.6, 129.0, 119.9, 104.5 and 86.4 mAh g(-1) at rates of 0.2, 5, 10, 15 and 20C, respectively. It still exhibits satisfactory cycle stability at room temperature (20 degrees C) and elevated temperature (55 degrees C), achieving 128.6 and 129.5 mAh g(-1) at 1 C with the capacity retention of 98% and 99.7% after 100 cycles, respectively. Besides, the favorable rate cycle performance at 55 degrees C has been shown to retain 95.2% of the maximum discharge capacity (102.7 mAh g(-1)) at 10C after 100 cycles. The stable structure, high reversibility and electrochemical reaction kinetics afforded by multiple ions existing in the spinel appear to contribute to the excellent electrochemical performance. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords:Lithium ion battery;Lithium nickel manganese oxide;Multiple substitutions;Rate capability;Cycle life