基于固-固反应机制锂硫电池的最新研究进展

Recent research progress of lithium⁃sulfur batteries based on solid⁃solid reaction mechanism

锂硫电池具有高的理论能量密度,且单质硫存在环境友好和价格低廉等优势,被认为是发展前景良好的储能器件。然而,硫在常规醚类电解液中进行充放电是基于固-液-固两相转换的反应机制,会生成溶解性较高的中间产物多硫化锂从而引发穿梭效应,导致活性物质不可逆流失和锂负极腐蚀。因此,发展不涉及液相多硫化锂溶解于电解液的固-固反应机制尤为重要。大量研究证明,通过优化正极材料设计、调控电解质体系及其协同设计等策略,可实现硫正极的固-固反应机制,避免多硫化锂溶解于电解液,从而提升锂硫电池的电化学性能。主要综述了硫正极实现固-固机制的可行途径并进行了机理探讨,最后对构筑高能量密度实用化锂硫电池的发展提出了展望,旨在解决贫电解液条件下锂负极腐蚀和硫正极基于固-固反应机制存在反应动力学缓慢的问题。

Lithium sulfur batteries are considered to be promising energy storage devices due to their high theoretical en⁃ergy density,as well as the advantages of environmental friendliness and low⁃cost of sulfur.However,sulfur cathodes usually react with lithium ions under solid⁃liquid⁃solid biphasic reaction mechanism in conventional ether⁃based electrolytes,which generates intermediate products of lithium polysulfides and leads to the irreversible loss of active materials and corrosion of lithium anodes.Hence,it is vital to develop sulfur cathodes operating on sold⁃solid reaction mechanism without dissolving of lithium polysulfides into electrolytes.At present,vast research revealed that the realization of sulfur cathodes based on solid⁃solid reaction mechanism could be achieved by rational design of cathode materials,regulating the electrolyte systems,or their synergistic design,which thus improved the electrochemical performance of lithium sulfur batteries.The strategies to⁃wards achieving solid⁃solid reaction mechanism of sulfur cathodes in recent years were summarized and the detailed mecha⁃nism was discussed.Finally,the development prospect of constructing practical lithium⁃sulfur batteries with high energy density was put forward,aiming at solving the problems of lithium anode corrosion under the condition of lean electrolyte and the sluggish reaction kinetics based on the solid⁃solid reaction mechanism of sulfur cathode.