Research On Preparation Of Layered LiMnO₂

The increasing demand for energy promotes the development of lithium-ion battery. Thelithium-ion batteries draw much attention due to its excellent characters, such as highoperating voltage, high energy density, good cycling performance, longevity, no memoryeffect and environment friendly. So it was known as green power in the 21st century and hasbeen widely applied. All these make the electrode materials of lithium-ion battery a focus ofmaterials research. However, applications of the lithium-ion battery were limited because ofthe problems of the cathode material. Consequently, research in the cathode material is themost critical in order to expand the applications of lithium-ion batteries and achieve thecommercialization.In this paper, the first chapter describes the development of lithium-ion battery andquantities of research in the cathode material of lithium-ion battery.The second chapter summarizes the variety of preparation methods and research status ofthe cathode materials layered lithium manganese oxide of lithium-ion battery.The third chapter explains the research of the Hydrothermal Synthesis of layeredLiMnO₂, and successfully prepared the layered LiMnO₂in a lower molar ratio of Li/Mn. Inthis paper, we prepared o-LiMnO₂mainly by hydrothermal synthesis and made a systematicstudy of its preparation process. The experimental results show that, with increasing of themolar ratio of Li/Mn as well as increasing of the reaction temperature and time, the purity ofo-LiMnO₂in the samples prepared was higher. The layered lithium manganese oxide preparedby Hydrothermal Synthesis is the orthometric o-LiMnO₂（PDF#35-0749）; the morphology ofthe sample is like-sphere powder and its particle size is small; partical diameter of o-LiMnO₂heated in 180℃for 10h is less than 0.232μm. We studied the electrochemical properties ofo-LiMnO₂which was prepared by Hydrothermal Synthesis and heated in 180℃for 10h. Itsefficiency of first charge-discharge is only 31%-45%. However, obtaining high purity layeredlithium manganese oxide （o-LiMnO₂） in a low molar ratio of Li/Mn is still a good guide forindustrial production. The fourth chapter mainly introduces the comparison of test results of several otherpreparation methods of layered lithium manganese oxide. Experimental results indicate thathigh-temperature solid-phase method is difficult in preparing the layered LiMnO₂, whenunder no protection of an inert atmosphere; Ion-exchange method can be used to preparem-LiMnO₂（PDF#52-1347）, but the cleaning of reaction impurities is so difficult that willaffect the final purity of the sample; o-LiMnO₂（PDF#23-0361） prepared by rheological phasemethod is different from the sample prepared by Hydrothermal Synthesis, the research on it isnot mature and still needed for further experiments to explain some key issues of it.