介孔碳/硫复合锂-硫电池正极材料与电化学性能

项目名称： 介孔碳/硫复合锂-硫电池正极材料与电化学性能

项目编号： No.51472148

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 尹龙卫

作者单位： 山东大学

项目金额： 88万元

中文摘要： 硫作为锂-硫电池正极材料虽然容量高，但其导电性差、循环性能不稳定，基于三维介孔与微孔碳的孔径可调、高比表面、导电性好、骨架相连等特点，在封装硫、改善锂-硫电池性能等具有独特的优势。本项目以介孔与微孔碳作为锂-硫电池正极固硫的基质材料，以水热化学方法制备三维有序的多孔结构碳/硫复合材料，实现硫在多孔碳内的尺寸、分布、含量等的控制，以SEM、TEM、XRD、XPS、Raman等研究材料的比表面、孔体积、孔径、化学键合态等微观结构。以恒流充放电法研究锂-硫电池的容量、循环稳定性与倍率性能。采用循环伏安与交流阻抗法研究多孔碳/硫复合电极与电解质界面发生的电化学过程与离子的嵌入和脱出机制，探讨锂-硫电池的容量衰减机制及改善循环稳定性和倍率性能的措施,分析电化学反应过程中硫与复合孔结构碳的协同作用、表界面效应等对电池电化学性能的影响规律。建立复合孔结构碳/硫复合材料增强锂-硫电池性能的机制与理论模型。

中文关键词： 新能源材料；碳材料；电化学性能；介孔材料

英文摘要： Lithium-sulfur battery based on sulfur cathode materials displays high specific capcity, low electron conductivity, cycle instability. Due to the adjustable pore size, high surface area, good electron conductivity, and inteconncted porous structure, three dimensional hierarchical mesoporous carbon has advantages in immobilizing sulfur and enhancing electrochemcial performance of Li-S battery. Three dimensional hierarchical ordered mesoporous carbon materials are synthesized via a hydrothermal chemcial reaction route using silica as a hard tempelate. Sulfur is immobilized in 3D mesoporous carbon to form mesoporous S/C compoiste as cathode materials for Li-S battery,with a contronllable size, distribution, content for sulfur within pores of C matrix. The surface area, pore volume, pore size distribution, chemical bonding state of the 3D mesoporous S/C compsites are invetigated using SEM, TEM, XRD, XPS, Raman techniques. Charge-discharge technique at a constant durrent is used to study the specific capacity, cycle stability and rate capacity of Li-S battery. Cyclic voltammetry and electrochemical impedance spectra are employed to characterize the electrochemical reaction process and ion intercalation and deintercalation mechanism taking place at the interface between porous carbon cathode and electrolyte. Capability fading mechanism, measures to improve cycle stability and rate capability of Li-S battery is invetigated. The synergistic effects between mesoporous carbon and sulfur, and intefacial effects on the elelctrochemical performance of S/C composite cathode is systematically analyzed and discussed. A systematic mechanism and theoretical model for enhancing electrochemical performance of mesoporous S/C composite cathode for Li-S battery is set up.

英文关键词： New energy materials;carbon materials;elelctrochemical performance;mesoporous materials