Synthesis And Electrochemical Properties Of Layered Cathode Materials For Lithium Ion Batteries

With the development of the times and the increasingly prominent contradiction between energy and environmental issues,the solution to this problem is imminent.Environmental pollution has forced people to find new clean energy to replace fossil fuels to meet the ever-growing requirement for energy.At present,investigation and development of new environment-friendly energy storage technologies is the key to achieve safe and reliable energy supply.Lithium ion batteries are one of the most potential electric energy storage devices because of their stable cycling lifespan,high energy density and environmental friendliness.They have potential applications in portable electronic devices such as digital cameras,laptops,electric vehicles,mobile phones and hybrid electric vehicles.Electrode material is the core of lithium ion battery,which is very important for improving the performance of lithium ion battery.Hence,it is urgently needed for the research and development of advanced electrode materials to meet the ever-increasing demands of the sustainable power sources in the modern electronics industry.In this paper,we have synthesized the layered lithium manganese oxide compound and layered molybdenum based metal oxide,and studied their electrochemical properties as the cathode materials of lithium ion batteries.The main research contents are as follows:?1?Mesoporous orthorhombic LiMnO2 has been directly fabricated by a one-step solid state method in this work.Benefiting from the unique mesoporous structure,the orthorhombic LiMnO2 prepared through calcinating the mixture of raw materials LiOH·H2O and Mn2O3 with various Li/Mn molar ratios shows enhanced lithium storage properties.When used as the cathode for lithium ion battery,the mesoporous orthorhombic LiMnO2 has been found to exhibit a maximum discharge capacity of 191.5 mAh g^-1 and a high reversible capacity of 162.6 mAh g^-1 after 50cycles with a 84.9%capacity retention at a current density of 0.1 C rate.These results demonstrate its potential application in high performance lithium ion batteries.?2??-MoO₃ nanowire bundles have been successfully prepared from the decomposition of self-assembled organic-inorganic precursor Mo₃O₁₀?C₆H₈N?₂·2H₂O nanowires.The preparation process needs no special equipment,which is easily to be scaled up under ambient pressure.The obtained samples have been fully analyzed by powder X-ray diffraction?XRD?,scanning electron microscopy?SEM?and X-ray photoelectron spectroscopy?XPS?.The as-obtained?-MoO₃ nanowire bundles,as for cathodes of lithium ion batteries,can initially reach a discharge capacity of 195 mAh g^-1and run up to 600 cycles with a 37%capacity retention at a current density of 100 mA g^-1.