Sulfhydryl‐functionalized COF‐based electrolyte strengthens chemical affinity toward polysulfides in quasi‐solid‐state Li‐S batteries
Linnan Bi,
Jie Xiao,
Yaochen Song,
Tianrui Sun,
Mingkai Luo,
Yi Wang,
Peng Dong,
Yingjie Zhang,
Yao Yao,
Jiaxuan Liao,
Sizhe Wang,
Shulei Chou
Affiliations
Linnan Bi
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Jie Xiao
National and Local Joint Engineering Research Center of Lithium‐ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Battery Materials of Yunnan Province, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology Kunming China
Yaochen Song
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Tianrui Sun
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Mingkai Luo
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Yi Wang
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Peng Dong
National and Local Joint Engineering Research Center of Lithium‐ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Battery Materials of Yunnan Province, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology Kunming China
Yingjie Zhang
National and Local Joint Engineering Research Center of Lithium‐ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Battery Materials of Yunnan Province, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology Kunming China
Yao Yao
National and Local Joint Engineering Research Center of Lithium‐ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Battery Materials of Yunnan Province, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology Kunming China
Jiaxuan Liao
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Sizhe Wang
Yangtze Delta Region Institute (Quzhou) University of Electronic Science and Technology of China Quzhou China
Shulei Chou
Institute for Carbon Neutralization, College of Chemistry and Materials Engineering Wenzhou University Wenzhou China
Abstract For lithium‐sulfur batteries (Li‐S batteries), a high‐content electrolyte typically can exacerbate the shuttle effect, while a lean electrolyte may lead to decreased Li‐ion conductivity and reduced catalytic conversion efficiency, so achieving an appropriate electrolyte‐to‐sulfur ratio (E/S ratio) is essential for improving the battery cycling efficiency. A quasi‐solid electrolyte (COF‐SH@PVDF‐HFP) with strong adsorption and high catalytic conversion was constructed for in situ covalent organic framework (COF) growth on highly polarized polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) fibers. COF‐SH@PVDF‐HFP enables efficient Li‐ion conductivity with low‐content liquid electrolyte and effectively suppresses the shuttle effect. The results based on in situ Fourier‐transform infrared, in situ Raman, UV–Vis, X‐ray photoelectron, and density functional theory calculations confirmed the high catalytic conversion of COF‐SH layer containing sulfhydryl and imine groups for the lithium polysulfides. Lithium plating/stripping tests based on Li/COF‐SH@PVDF‐HFP/Li show excellent lithium compatibility (5 mAh cm−2 for 1400 h). The assembled Li‐S battery exhibits excellent rate (2 C 688.7 mAh g−1) and cycle performance (at 2 C of 568.8 mAh g−1 with a capacity retention of 77.3% after 800 cycles). This is the first report to improve the cycling stability of quasi‐solid‐state Li‐S batteries by reducing both the E/S ratio and the designing strategy of sulfhydryl‐functionalized COF for quasi‐solid electrolytes. This process opens up the possibility of the high performance of solid‐state Li‐S batteries.
