Promoting the sulfur redox kinetics by mixed organodiselenides in high-energy-density lithium–sulfur batteries
Meng Zhao,
Xi-Yao Li,
Xiang Chen,
Bo-Quan Li,
Stefan Kaskel,
Qiang Zhang,
Jia-Qi Huang
Affiliations
Meng Zhao
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China; Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Xi-Yao Li
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
Xiang Chen
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
Bo-Quan Li
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China; Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Stefan Kaskel
Department of Inorganic Chemistry, Technische Universität Dresden, Bergstr. 66, Dresden 01069, Germany
Qiang Zhang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Corresponding authors.
Jia-Qi Huang
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China; Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China; Corresponding authors.
Lithium–sulfur (Li–S) batteries are considered as a highly promising energy storage system due to their ultrahigh theoretical energy density. However, the sluggish kinetics of the complex multi-electron sulfur redox reactions seriously hinders the actual battery performance especially under practical working conditions. Homogeneous redox mediation, through elaborately designing the additive molecules, is an effective approach to promote the sulfur redox kinetics. Herein a promoter of mixed organodiselenides (mixed-Se) is proposed to comprehensively improve the sulfur redox kinetics following the redox comediation principles. Concretely, diphenyl diselenide promotes the liquid–liquid conversion between polysulfides and the solid–liquid conversion regarding lithium sulfide oxidation to polysulfides, while dimethyl diselenide enhances the liquid–solid conversion regarding lithium sulfide deposition. Consequently, the mixed-Se promoter endows a high discharge capacity of 1002 mAh g−1 with high sulfur loading of 4.0 mg cm−2, a high capacity retention of 81.6% after 200 cycles at 0.5 C, and a high actual energy density of 384 Wh kg−1 at 0.025 C in 1.5 Ah-level Li–S pouch cells. This work affords an effective kinetic promoter to construct high-energy-density Li–S batteries and inspires molecular design of kinetic promoters toward targeted energy-related redox reactions.
