高性能锂硫电池正极用碳基材料的表、界面修饰

Carbon materials with modified surfaces and interfaces for the high performance cathode of lithium sulfur batteries

锂硫电池的理论能量密度为2600 W·h/kg,是常规锂离子二次电池的3~5倍,是目前最有可能产业化的下一代二次电池技术之一,因此近年来引起了研究人员的广泛关注。然而单质硫与Li2S的低电导率、充放电过程中单质硫的体积膨胀、电化学反应中间产物多硫化锂的"穿梭效应"及最终放电产物的不可控沉积等问题降低了活性物质的利用率和电池的循环寿命,严重阻碍了锂硫电池的商业化进程。在锂硫电池正极材料的改性方法中,将单质硫与表、界面修饰的碳基材料复合制备出多功能碳/硫复合材料是提高电池性能地有效手段。本文概括综述了近几年来碳基材料的表、界面修饰及在锂硫电池正极中的应用。

Lithium-sulfur （Li-S） battery, has attracted tremendous attention from the energy storage community, mainly due to its high theoretical energy density （-2600 W·h·kg-1）, which is twice more than that of conventional Li-ion batteries. However, the commercialization of Li-S battery technology is hindered by technical obstacles, such as the poor intrinsic electronic conductivity of sulfur and final discharge products （Li2S/Li2S2）, the high dissolution of intermediate product lithium polysulphides （LiPSs）, large volumetric expansion （76%） of sulfur cathode during the lithiation, and the irreversible phase transformation and uncontrolled deposition of Li2S. Fortunately, intense research efforts have been devoted to overcoming these unsolved issues. Among these efforts, the most effective strategy is constructing nanocomposite cathodes composed of sulfur with surface and interface decorated carbonaceous materials. Carbon materials with modified surfaces and interfaces for advanced Li-S batteries are summarized in this paper.