“丝瓜瓤”状微纳结构硫碳复合正极材料的可控制备与构效关系研究

项目名称： “丝瓜瓤”状微纳结构硫碳复合正极材料的可控制备与构效关系研究

项目编号： No.51474243

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 赖延清

作者单位： 中南大学

项目金额： 80万元

中文摘要： 锂硫电池具有能量密度高、原料廉价、环境友好等优点，应用前景广阔。目前锂硫电池主要存在活性物质利用率低、倍率性能差以及循环性能不理想等问题。本课题通过设计具有丝瓜瓤状微纳结构的硫碳复合电极材料，旨在实现硫电极材料的高载硫量、高活性物质利用率与高稳定化。拟以不同长径比的中空炭纤维为原料，采用活化工艺，对其孔隙结构、孔径分布及比表面积进行调控，获得丝瓜瓤状中空多孔炭纤维；在此基础上，采用真空辅助液相沉积+热处理工艺，将活性物质纳米硫高效负载到中空多孔炭纤维的多尺度孔隙中；研究复合电极材料组成、结构、形貌、界面性质与其电化学性能的相互关系，探明高效负载硫的控制机制。研究复合电极材料的电极过程动力学及其储能机理，阐明影响硫碳复合材料动力学稳定性的关键限制因素。基于以上研究，确定并实现高容量、长寿命微纳结构硫碳复合正极材料的制备，为锂硫电池的开发与应用提供支撑。

中文关键词： 锂硫电池；硫碳复合材料；中空炭纤维；活化；构效关系

英文摘要： Lithium-sulfur battery holds great potential due to its high theoretical specific capacity of 1675 mAh/g and specific energy of 2567 Wh/kg. Meanwhile, sulfur as a cathode material has the advantages of low cost, natural abundance and non-toxicity. However, the development of lithium-sulfur battery has met several challenges for its typically low sulfur utilization, low rate capacity, and poor cycle life.This project designs Luffa-sponge-like micro-/nano-structured sulfur-carbon composite electrode materials to achieve high sulfur content,high utilization and high stability of the sulfur electrode materials. With different aspect ratios of hollow carbon fibers as raw materials, the Luffa-sponge-like hollow porous carbon fibers are obtained by using pretreated process and activation process to regulate pore structure, pore size distribution and specific surface area. The nanoscale sulfur are immobilized with high efficiency into different-structured hollow porous carbon fibers using heterogeneous sulfur nucleation and heat treatment process. Then the relationships between the composition, structure, morphology, interfacial interaction of the composite electrode materials and their electrochemical properties are investigated. The control mechanism of high-efficiency sulfur immobilization is explored. The electrode kinetics of the composite electrode materials during the charging and discharging process is studied. Finally we clarify the mechanism of the composite electrode materials during the charge-discharge process and the key factors affecting the kinetic stability of the sulfur-carbon composite materials.Based on the research, we identify and achieve the preparation of high-capacity and long-life micro-/nano-structured sulfur-carbon composite cathode materials and providing guidance for the practical application of lithium-sulfur battery.

英文关键词： Lithium-sulfur battery;Sulfur-carbon composite;Hollow carbon fiber;Activation;Structure-activity relationship