Affiliation:
1. State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China
2. Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China
Abstract
AbstractLithium–sulfur (Li–S) batteries offer high theoretical capacity but are hindered by poor rate capability and cycling stability due to sluggish Li2S precipitation kinetics. Here a sulfonate‐group‐rich liquid crystal polymer (poly‐2,2′‐disulfonyl‐4,4′‐benzidine terephthalamide, PBDT) is designed and fabricated to accelerate Li2S precipitation by promoting the desolvation of Li+ from electrolyte. PBDT‐modified separators are employed to assemble Li–S batteries, which deliver a remarkable rate capacity (761 mAh g−1 at 4 C) and cycling stability (500 cycles with an average decay rate of 0.088% per cycle at 0.5 C). A PBDT‐based pouch cell even delivers an exceptional capacity of ≈1400 mAh g−1 and an areal capacity of ≈11 mAh cm−2 under lean‐electrolyte and high‐sulfur‐loading condition, demonstrating promise for practical applications. Results of Raman spectra, molecular dynamic (MD) and density functional theory (DFT) calculations reveal that the abundant anionic sulfonate groups of PBDT aid in Li+ desolvation by attenuating Li+‐solvent interactions and lowering the desolvation energy barrier. Plus, the polysulfide adsorption/catalysis is also excluded via electrostatic repulsion. This work elucidates the critical impact of Li+ desolvation on Li–S batteries and provides a new design direction for advanced Li–S batteries.
Cited by
1 articles.
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