随着石墨负极的成功商用,锂离子电池在智能手机、笔记本电脑等便携式电子设备中已得到广泛的应用。经过20多年的发展,现有基于嵌锂化合物正极的锂离子电池已接近其理论容量,但仍不能满足高速发展的电子工业和新兴的电动汽车等行业的要求,寻找具有更高能量密度的电池系统迫在眉睫。锂硫电池系统具有极高的理论能量密度,在多种储能系统中是最具潜力的一种二次电池。但是锂硫电池中也存在硫的电导率极低、多硫化物溶解迁移等问题,使其在走向实用化的过程中遇到许多困难。纳米碳质材料在新型锂硫电池的开发过程中处于重要地位,通过纳米炭的引入,可以获得导电复合正极材料,控制多硫化物的穿梭,从而有望实现正极硫材料的高效利用。综述了基于纳米炭-硫复合正极材料,尤其是碳纳米管、石墨烯、多孔炭以及其杂化物等材料复合的电极,分析其结构与锂硫电池性能的关系,并展望锂硫电池的发展方向。
Lithium-ion batteries ( LIBs) are extensively used in numerous portable devices such as smart-phones and laptops. However, current LIBs based on the conventional intercalation mechanism cannot meet the requirements of the electronics industry and electric vehicles although they are approaching their theoretical capacity. Therefore, it is extremely urgent to seek for systems with higher energy densities. Among various promising candidates, lithium-sulfur (Li-S) batteries with a high theoretical capacity are very attractive. However, the commercial use of Li-S batteries still faces obstacles such as the low electrical conductivity of sul-fur and lithium sulfide and the dissolution of polysulfides. The introduction of nanocarbon materials into Li-S batteries sheds light on the efficient utilization of sulfur by improving the conductivity of the composites and restraining the shuttle effect of polysulfides. Here, we give a brief review of recent progress on carbon/ sulfur composites, especially carbon nanotube-, graphene-and porous car-bon-based hybrids, new insights on the relationships between the structure and the electrochemical performance, and propose some important aspects for the future development of Li-S batteries.