超细Si颗粒镶嵌纳米多孔碳纤维的制备及其在锂离子电池负极中的应用

项目名称： 超细Si颗粒镶嵌纳米多孔碳纤维的制备及其在锂离子电池负极中的应用

项目编号： No.11504147

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 刘德全

作者单位： 兰州大学

项目金额： 24万元

中文摘要： 本项目拟采用等离子体CVD方法制备出直径和掺杂浓度可控的超细Si颗粒，并结合电纺丝技术制备出具有多孔结构的超细Si颗粒镶嵌多孔纳米碳纤维，探索复合纤维在高性能锂离子电池负极中的应用。研究等离子体CVD参数对制备出纳米颗粒的形貌、均匀性、晶体结构和产率的影响，优化实验条件，实现对超细硅颗粒的可控制备；探索以超细Si颗粒为硅源，利用电纺丝技术结合热退火工艺制备孔结构可控的 3D 纳米多孔碳硅复合电极的最佳工艺路线。系统研究探索硅颗粒的尺寸、掺杂浓度、晶体结构、在碳纤维中的分布方式，以及硅碳复合纤维的不同孔状结构对锂离子二次电池性能的影响，获得具有优异充放电性能和循环稳定性（比容量高于1500 mAh/g，循环次数大于500次）的锂离子电池样品，为硅碳复合材料在锂离子电池中的应用提供可靠的实验数据和有价值的技术方案。

中文关键词： 纳米复合结构；锂离子电池；负极材料；电化学性能；储锂机理

英文摘要： In this project, we intend to design and fabricate ultra-small Si particles inlay 3D porous carbon fibers as anode for high performance Li-ion batteries via two-step process. Firstly, we intend to prepare ultra-small Si nanoparticles with controllable diameter and doping concentration material via Plasma Enhanced Chemical Vapor Deposition (PECVD). The effects of deposition conditions on the morphology, uniformity, crystal structure and productivity of Si nanoparticles will be researched, so that controllable fabrication of ultra-small Si particles be achieved. And then ultra-small Si inlay porous carbon fibers will be fabricated via electrospinning by using the obtained Si nanoparticles as Si source. By developing an optimal route to prepare Si inlay carbon fiber with controllable diameter of carbon fibers and dispersion of Si nanoparticles via electrospinning, and investigating the formation mechanism of 3D pores during the annealing, we try to obtain ultra-small Si particles inlay 3D porous carbon fibers electrode with large contact area and low resistance. The capacity, (dis-)charge performance at high rate and cycling stability of the obtained electrodes will be investigated as a function of the component, pore diameter, porosity, conductivity and mechanical property of the current collectors, as well as the characterisics of Si nanoparticle. Finally we intend to obtain a anode of lithium ion batteries with specific capacity over 1500 mAh/g after cycling over 500 cycles. The project will provide reliable experimental data and valuable technical solutions for the developments and applications of lithium ion batteries with Si-C composite anodes.

英文关键词： Nanocomposite structure;Lithium ion battery ;Anode;Electrochemical property;Mechanism of lithium storage