Preparation And Application Of Foamed Mesoporous Carbon/Silicon Composite Anode Materials For Lithium Ion Batteries

The energy crisis has severely constrained China’s sustainable development.The development and application of new high-performance energy storage technologies have become one of the effective ways to solve the energy crisis.Lithium-ion batteries have been widely used as a variety of energy storage devices due to their high-density power,long-lasting charge-discharge cycles,and reasonable voltage performance,and are considered representative of modern high-performance batteries.In order to overcome the shortcomings of silicon diffusing powder in the charge-discharge process of existing lithium-based silicon-based materials and the poor compatibility between silicon and carbon,this paper uses a lithium-ion battery silicon-doped carbon porous composite anode material for high-capacity applications.Lithium-ion batteries are the research and application background.The prepared silicon-doped carbon mesoporous composites can provide necessary buffer space to reduce the huge volume change and continuous pressure change during the lithium insertion process,and effectively solve the lithium-silicon powder.Difficulties,while silicon is more evenly dispersed in the carbon matrix.In this paper,the research contents are as follows:（1）Preparation of silicon-doped carbon macroporous composite thin films for lithium-ion batteries by means of vapor deposition and foaming pore formation processes through high-temperature carbon pyrolysis,foam pore-forming agent sublimation and carbon coating.The silicon nano-particles were oxidized,hydroxyl groups were attached,and the surface of the organosiloxane was modified to study the oxidation thickness of the silicon nano-particles.The surfaces of the silicon nano-particles were modified by SEM,TEM,and nitrogen adsorption desorption tests.Hole structure.When the film is used as a negative electrode material for a lithium ion battery,the capacity of the first inserted lithium is 1045 mAh g^-1,the delithiation capacity is 961 mAh g^-1,the Coulomb efficiency is 91.96%,and the Coulomb efficiency is 88.10%after 100 cycles,indicating that the charge is good.Discharge performance.（2）A method for preparing a sample of lithium ion-silicon-doped carbon porous composite negative electrode material was sequentially prepared by sequentially preparing m（Si）:m（PTA）=1:15,1:30,1:45,1:60,1:75 samples of silicon-doped carbon porous composite anode materials A,B,C,D and E.The pore structure was observed by SEM,and the specific surface area pore analyzer was used to test samples to calculate the ratio of the anode materials obtained under different preparation conditions.Surface and pore volume and pore size data.At the same time,the electrochemical performance of samples A,B,C,D,and E was evaluated.The mass ratio of silicon nanoparticles and foaming agent was evaluated for the cell structure and electrochemical performance of the material.Influence laws,find the best mass ratio of silicon nanoparticles and foaming agent,and explore the foaming mechanism of foaming agent PTA in the material.Among them,the mesoporous material sample D is the best,the BET specific surface area is about 568.71 m² g^-1,the average cell diameter is 24 nm,the initial discharge capacity is 1627.6 mAh g^-1,the charge capacity is 1597 mAh g^-1,and the Coulomb efficiency is 92.02%,100 cycles of capacitance have a high retention capacity and electrochemical performance is improved.