固固转化反应硫正极的研究进展

Lithium sulfur (Li-S) battery is considered one of the most promising secondary batteries because of its ultra-high theoretical energy density and abundant sulfur resources. The sulfur cathode in a typical liquid Li-S battery undergoes a "solid-liquid-solid" conversion reaction, which produces soluble polysulfides throughout the charging and discharging process, causing the shuttle effect and resulting in active material loss and inadequate cycle life. The "solid-solid" conversion reaction of the sulfur cathode has been suggested and investigated to avoid the production of soluble long-chain polysulfides and essentially solve the shuttle problem. Various methodologies and research advances toward establishing a "solid-solid" conversion process in the sulfur cathode are discussed in this study. The sulfur limitation mechanisms in microporous structures, covalent sulfur fixing in organic polymers, inorganic heteroatom doping, and organic polymer skeleton/inorganic hybrid synergy are reviewed. Meanwhile, their optimization and enhancement techniques and future challenges are summarized. Furthermore, the solid-state electrolyte paired with the sulfur-positive electrode of the solid-solid conversion process is discussed, followed by a brief introduction to the common techniques of "quasi-solid" phase conversion. Finally, we propose the development of a high-energy density Li-S battery.

Keywords： solid-solid conversion reaction ; confining sulfur within microporous carbon ; covalent sulfur fixation in organic substance ; organic/inorganic synergistic sulfur fixation