Research On Modified Graphite Based On High Temperature And High Pressure As Anode Material For Lithium-ion Battery

The global energy crisis and environmental pollution have triggered a huge demand for sustainable energy and energy storage devices.Among them,in the field of energy storage,lithium-ion batteries are more favored by consumers because of their low cost,high performance,and high safety.However,for the current negative graphite of commercial lithium-ion batteries,there are two common problems: artificial graphite is low in production efficiency and expensive,while low-cost natural graphite has poor performance and has been classified as a supply risk material.Therefore,it is particularly important to find low-cost graphite as a negative electrode material,such as graphite waste.In fact,graphite has a wide range of applications,such as chemical industry,machinery,electronics industry and national defense.Among them,the amount of natural graphite used and graphite waste produced in the synthetic diamond industry are many every year.From this we speculate that if these graphite wastes treated with high temperature,high pressure and catalysts can be transformed into lithium-ion battery anode materials,then graphitebased anode materials will be a supplement.However,there are no relevant reports on this research.To this end,we conduct the following research on various types of graphite used for diamond synthesis and the graphite waste produced by it.(1)In order to gain insight into the structure and electrochemical properties of graphite waste,first of all,the morphology,structure and electrochemical properties of natural flake graphite and after etching,oxidation and coating are studied.(2)The morphology,structure and electrochemical properties of industrial grade diamond waste graphite and after etching and oxidation are studied.Compared with natural graphite,most industrial grade diamond waste graphite has a transparent pore structure.At a current density of 0.1C,the specific discharge capacity of the waste graphite stabilized at396.9mAh/g after 200 cycles;under oxidation at 480°C in air,the specific discharge capacity stabilized at 349mAh/g after 100 cycles.The specific discharge capacity is stable at 281mAh/g after 100 cycles of KOH etching at 900 ℃.(3)The morphology,structure and electrochemical properties of waste gem-grade diamond graphite and modified by etching and oxidation are studied.The study found that when the current density is 0.1C,the specific discharge capacity of recrystallized graphite after 100 cycles is 288.6mAh/g;under oxidation at 480°C in air,the specific discharge capacity is 307.8mAh/g after 100 cycles.The specific discharge capacity is 341mAh/g after100 cycles of KOH etching at 1000°C.In a word,through the above research,the graphite waste after diamond synthesis can be transformed into a negative electrode material for lithium-ion batteries.