The characterization and electrochemical performance of Li [Li0.2Ni0.4Mn0.4]O2 material prepared by a combustion method

A Li[Li0.2Ni0.4Mn0.4]O-2 cathode material for lithium battery was synthesized in de-ionized water, ethanol and ethanol with PEG by a combustion method. XPS analysis shows that Ni and Mn are in 3+ and 4+ oxidation states, respectively. Three materials exhibit a layered hexagonal alpha-NaFeO2 structure, and that prepared in ethanol with PEG displays the best homogeneous morphology in a size distribution of 200 -400 nm. The electrochemical tests show that the material prepared in ethanol with PEG displays the best cyclic performance and rate capability, such as the discharge capacity of 254 mAhg(-1) in the first cycle at 0.1C and 234 mAhg(-1) after 50 cycles. Capacity retention is more than 90% after 50 cycles for the cell with a charge/discharge pre-cycling treatment (one cycle at 4.5-2.0 V and followed by one cycle at 4.8-2.0 V) compared with that without pre-cycling. EIS measurements demonstrate that pre-cycling treatment leads to form a better SEI layer and the cell assembled with the material prepared in ethanol with PEG has the least R-SEI and R-ct values. (C) 2014 Elsevier B.V. All rights reserved.