Preparation And Properties Studies Of Low Cost New Electrode Materials For Li-ion Battery

Lithium ion batteries have been widely used due to their advantages such as high energy density,small size,and light weight.However,at present,the cost of lithium ion battery electrode materials is still high,which limits the application of lithium ion batteries in grid-side energy storage and other fields.Therefore,it is necessary to study and develop new lithium ion battery electrode materials with lower costs.TiO₂has the characteristics of abundant,low cost,and environmental friendliness.It has a high theoretical specific capacity?335 m Ah/g?when used as a negative electrode material for lithium ion batteries.However,the poor conductivity of Ti O₂and the slow diffusion of lithium ions limit its practical application.In this thesis,a series of nanoporous titania/carbon composite new materials were prepared by calcining the titanium oxide cluster precursors in air and nitrogen atmosphere.The microstructure and physicochemical properties of these new materials were analyzed.The ralation of the way of prepare and the microstructure with the electrochemical performance of the material were studies,which provides a theoretical basis and experimental fundamentals for the preparation of titanium-based lithium ion battery anode materials with excellent performance.Fluorides such as Fe F₃and Fe F₂are a new type of cathode materials for lithium-ion batteries,which have a higher theoretical specific capacity?Fe F₃,712m Ah/g;Fe F₂,571 m Ah/g?and lower cost.But iron-based fluorides has slowness of the ion diffusion,low of the electron transfer rate and their crystal structure changes significantly during charge and discharge,resulting in poor cycle stability of this type of material.To solve this problem,this thesis prepared polyaniline-coated Fe F₃and polyaniline-coated Fe F₂cathode materials for lithium-ion batteries by chemical oxidation,and studied their electrochemical properties.Using industrial solid waste as a raw material to prepare lithium ion battery electrode materials not only helps to explore new ways of industrial solid waste resource utilization,but also helps reduce the cost of lithium ion batteries.Therefore,this paper also tried to use industrial solid waste flue ash as a negative electrode material for lithium ion batteries.Electrochemical studies have shown that the first discharge specific capacity of material has a 214.7 m Ah/g at a voltage range of 0-2.5V and a current density of 200 m A/g,after 100 charge and discharge cycles,the capacity is still 131.6 m Ah/g.