SiO2催化制备煤基石墨及其电化学性能研究OA北大核心CSTPCD

Graphite is widely used as a negative electrode material in lithium-ion batter-ies.With the increasing demand for lithium-ion batteries,coupled with the declining production of natural graphite,has the sustainable supply pressure of high-quality negative electrode materi-als continues to increase.Hence,there is a need to develop high-performance synthetic graphite as an alternative to natural graphite.Porous anthracite-based graphite with a stable and hierarchi-cal pore structure was synthesized from Taixi anthracite using SiO2 catalysis,oxidation-induced micro-expansion,and pore formation through activation.The electrochemical properties of the porous anthracite-based graphite as a negative electrode material subsequently were analyzed.The results show that with the increase of SiO2 content in the catalyst,the degree of graphitiza-tion and the orderliness of graphite crystal structure of coal-based graphite gradually increase;af-ter the oxidation-induced micro-expansion treatment,the spacing of coal-based graphite layers and the number of medium and large pores are enlarged.The ordering degree of coal-based graphite crystal structure decreases,generating a significant amount of defect structures.After the activation pore formation,the micromorphology of coal-based graphite changes significantly,leading to an increase in the number of micropores and a well-defined pore structure.With the mass fraction of SiO2 of 20%,the graphitization degree of anthracite-based graphite reaches 89.3%,and the spacing between graphite crystallite layers increases from 0.336 32 nm to 0.338 09 nm following oxidation-induced micro-expansion treatment.The specific surface area increases from 4.171 20 m2/g to 29.471 00 m2/g.After activation pore formation,the pore structure of porous anthracite-based graphite further developes significantly,resulting in an increase in the specific surface area of micropores from 2.949 90 m2/g to 8.150 60 m2/g.With the mass fraction of SiO2 of 20%,the porous anthracite-based graphite exhibites an initial reversible specific capacity of 298.0 mAh/g and a coulombic efficiency of 67.41%at a multiplying of 0.1 C.After 110 cycles at a multiplying of 1 C,the reversible specific capacity measures 234.1 mAh/g,retaining 95.1%of its capacity,with the coulombic efficiency consistently remaining near 100%.Anthracite,after undergoing SiO2 catalysis,oxidation-induced micro-expansion,and activation pore formation dur-ing the graphitization process,can yield porous anthracite-based graphite with favorable electro-chemical properties.