Preparation And Study On Anode Materials Of Lithium-ion Batteries

Lithium-ion batteries are green and rechargeable secondary power,they are widely used in mobile phones,notebook computers and other equipments,due to high working-voltage,large energy density.The emphases on lithium-ion batteries are further to improve their Performances and reduce their costs.Carbon materials are one of the available approaches that enhance the performances and decrease the costs of lithium-ion batteries,since there are a variety of species of carbon materials and their properties improvement would be effective to upgrade the anode.The thesis was concerned on the structures and performances of anode materials,and hopes to find ideal materials.In the present study,natural graphite,which has good lithium storage performance and bad compatibility with electrolyte,was deep investigated for preparing excellent performance and low cost anode materials for Lithium ion battery.Two methods ,liquid-phase oxidation (including H₂O₂ oxidation and Ce(SO₄)₂ oxidation) and coating were used to improve the surface of the natural graphite.The surface morphology, structure and charge-discharge performance were investigated using XRD EIS and constant-current charge-discharge experiments.The results of experiment show that:1. The XRD result showed that composite material still held the samdwich configuration of nature graphite.2. The EIS result showed that impedance increased while the thickness added.3. The discharge curve of composite materials which were coated by Poly(ethylene oxide) and carboxymethyl cellulose was smooth, after 50 charge/discharge cycles, capacity of discharge still remain 300mAh·g^-1 ,while Nature graphite's capacity rapid reduced after 30 cycles. Pyrolytic carbon released form cmc and Poly(ethylene oxide) could cover graphite satisfactorily and the disordered structure of pyrolytic carbon on the surface of graphite can...