高容量摇铃式Li4Ti5O12-M@C复合负极材料的制备与电化学性能研究

项目名称： 高容量摇铃式Li4Ti5O12-M@C复合负极材料的制备与电化学性能研究

项目编号： No.21206203

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 化学工程及工业化学

项目作者： 胡学步

作者单位： 重庆理工大学

项目金额： 25万元

中文摘要： 尖晶石型Li4Ti5O12的理论容量低和嵌锂电位高，导致其能量密度较低，严重限制了它的大规模实际应用。由于M材料（M = Sn, Si, Sb, Bi）具有高的理论容量和较低的嵌锂电位，本项目拟分别以SiO2和C作为空腔填充物，采用碳热还原法合成一系列摇铃式Li4Ti5O12-M@C复合负极材料。M纳米颗粒处于中空腔体内可以有效缓解它们在充放电过程中巨大的体积膨胀，并在壳内与Li4Ti5O12核均匀复合，提高了复合材料的放电容量。同时综合导电碳包覆与纳米化的优势，改善其功率密度与循环性能。深入研究微粒形貌、粒度分布、比表面积、电子电导、锂离子电导和嵌锂电位对复合材料放电容量、功率密度及循环寿命的影响，探究协同效应、微观结构和宏观性质之间的相互关系。考察空腔体积、组成含量、纳米尺寸和导电碳包覆等关键因素对复合材料性能的影响。

中文关键词： 复合负极材料；Li4Ti5O12；高容量；长寿命；锂离子电池

英文摘要： Due to low theoretical capacity and high lithium intercalation voltage, spinel Li4Ti5O12 has a lower energy density which prohibits its use in practical large-scale applications. In this project, rattle-type structured Li4Ti5O12-M@C composite anode materials will be synthesized by carbothermal reduction method using SiO2 or C as the spacer layer materials because M materials (M = Sn, Si, Sb, Bi) have high theoretical capacity and low lithium intercalation voltage. The spacer layer can effectively alleviate large volume expansion of M nanoparticles during charge-discharge process. In the shell, the uniform mixing of Li4Ti5O12 core and M nanoparticles will increase discharge capacity of the composite materials. Moreover, power density and cycling performance can be improved by conductive carbon coating and nano-size. The physical and electrochemical properties of the composite materials will be examined, including particle morphology, particle size distribution, specific surface area, electronic conductivity, lithium-ion conductivity and lithium intercalation voltage. The effects of these properties on the discharge capacity, the power density and the cycling life will be systematically studied. The relationships between synergistic effect, microscopic structure and macroscopic properties will be explored. Further

英文关键词： composite anode materials；Li4Ti5O12；high capacity；long life；lithium-ion battery