Abstract
Both Li2MnO3 and LiNi1/3Co1/3Mn1/3O2 are layered structure, and they can be mixed to form a solid solution Li2MnO3．LiNi1/3Co1/3Mn1/3O2, which its charge-discharge region between 2 and 4.8 V. This material will release Li2O due to Li2MnO3 irreversible decomposition when voltage are above 4.5 V in the first charge cycle, and that’s the reson for loss of capacity in the first cycle. This experiment is composed by three part. First, I will discuss how the pH value affect the electrochemical performances when preparing Li2MnO3．LiNi1/3Co1/3Mn1/3O2 precursor through co-precipitation method. The second and the third parts will take apart Li2MnO3．LiNi1/3Co1/3Mn1/3O2 into Li2MnO3 and LiNi1/3Co1/3Mn1/3O2. We try to prepare Li2MnO3 and LiNi1/3Co1/3Mn1/3O2 through hydrothermal and co-precipitatio method, respectively, and observe how the order of these two step processes affect the electrochemical performances. In my report,process that using hydrothermal method to prepare Li2MnO3 first then co-precipitaion method to prepare LiNi1/3Co1/3Mn1/3O2 thereafter can lower the capacity loss in the first cycle, and even have higher capacity and better cycle ability comparing to Li2MnO3．LiNi1/3Co1/3Mn1/3O2 prepared by co-precipitation method.