A New Hydrophilic Binder Enabling Strongly Anchoring Polysulfides for High‐Performance Sulfur Electrodes in Lithium‐Sulfur Battery |
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| Authors: | Wei Chen Tianyu Lei Tao Qian Weiqiang Lv Weidong He Chunyang Wu Xuejun Liu Jie Liu Bo Chen Chenglin Yan Jie Xiong |
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| Institution: | 1. State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, China;2. Soochow Institute for Energy and Materials Innovations, College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, China;3. Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, China;4. School of Energy Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China;5. Institute of Microelectronics of Chinese Academy of Sciences, Beijing, China |
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| Abstract: | As one of the important ingredients in lithium‐sulfur battery, the binders greatly impact the battery performance. However, conventional binders have intrinsic drawbacks such as poor capability of absorbing hydrophilic lithium polysulfides, resulting in severe capacity decay. This study reports a new type of binder by polymerization of hydrophilic poly(ethylene glycol) diglycidyl ether with polyethylenimine, which enables strongly anchoring polysulfides for high‐performance lithium sulfur batteries, demonstrating remarkable improvement in both mechanical performance for standing up to 100 g weight and an excellent capacity retention of 72% over 400 cycles at 1.5 C. Importantly, in situ micro‐Raman investigation verifies the effectively reduced polysulfides shuttling from sulfur cathode to lithium anode, which shows the greatly suppressed shuttle effect by the polar‐functional binder. X‐ray photoelectron spectroscopy analysis into the discharge intermediates upon battery cycling reveals that the hydrophilic binder endows the sulfur electrodes with multidimensional Li‐O, Li‐N, and S‐O interactions with sulfur species to effectively mitigate lithium polysulfide dissolution, which is theoretically confirmed by density‐functional theory calculations. |
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| Keywords: | binders lithium‐sulfur batteries polysulfides |
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