受传统正极材料自身储锂容量的限制，锂离子电池的实际能量密度较低。为满足电动汽车发展的要求，需要发展新一代的动力电池体系。具有高能量密度的锂-硫电池颇具发展潜力。. 致力于解决锂-硫电池库伦效率低、容量衰减快、循环寿命短以及采用金属锂负极所存在的安全隐患问题，本项目拟在纳米尺度上设计和制备硅/碳、硫/碳复合纤维电极，系统研究它们在锂-硫电池中的应用。拟采用高效率的电纺丝技术并结合后处理工艺，制备出直径、长度、结构和成分可控的硅/碳、硫/碳和碳多孔纳米纤维，提出改善硅和硫的电化学特性、阻止多硫化锂在电解液中溶解、抑制“飞梭”效应的有效途径。以优化制备的锂化硅/碳负极、硫/碳正极组装出能量密度≥500 Wh/kg、循环次数≥500次、容量保持率＞80%的锂-硫电池原型器件。项目的实施将为能量密度高、循环寿命长、安全性好的锂-硫电池的研发提供可靠的基础实验数据和有价值的技术方案。

Due to the lower specific capacity of the traditional cathode materials, the energy densities of the commercial lithium-ion batteries are small. In order to meet the needs of longer-range electric vehicles, it is necessary to develop the new-generation power batteries. Lithium-sulfur battery is a potential candidate owing to its high energy density.. Devoting to solve the problems of the low coulombic efficiency, rapid capacity fade, poor cycle life and safety hazard for current lithium-sulfur batteries, the present project plans to design and fabricate the electrodes of silicon/carbon and sulfur/carbon composite nanofibers, and systematically investigate their application in lithium-sulfur batteries. We intend to prepare the composite nanofibers and porous carbon nanofibers with controllable diameters, lengths, structures and compositions using a low-cost and high-efficiency electrostatic spinning technique followed by some post-treatment processes, and try to find out effective approaches to improve the electrochemical performances of silicon and sulfur, prevent the dissolution of polysulfides in electrolyte, and suppress the shuttle effect. With the optimized lithiated-silicon/carbon nanofibers anode and the sulfur/carbon nanofibers cathode, we expect to assemble a prototype device of lithiated silicon-sulfur battery with a energy density higher than 500 Wh/kg, a cycle life longer than 500 times, and a capacity retention larger than 80%. The project implemention will provide reliable basic experimental data and valuable technical solutions for developing lithium-sulfur batteries with high energy density, long cycle life and good safety.