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High Sulfur Content Material with Stable Cycling in Lithium‐Sulfur Batteries
Author(s) -
Preefer Molleigh B.,
Oschmann Bernd,
Hawker Craig J.,
Seshadri Ram,
Wudl Fred
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201708746
Subject(s) - polysulfide , faraday efficiency , sulfur , cathode , raman spectroscopy , cycling , chemistry , lithium (medication) , chemical engineering , materials science , electrochemistry , electrolyte , organic chemistry , electrode , medicine , physics , archaeology , engineering , optics , history , endocrinology
We demonstrate a novel crosslinked disulfide system as a cathode material for Li‐S cells that is designed with the two criteria of having only a single point of S−S scission and maximizing the ratio of S−S to the electrochemically inactive framework. The material therefore maximizes theoretical capacity while inhibiting the formation of polysulfide intermediates that lead to parasitic shuttle. The material we report contains a 1:1 ratio of S:C with a theoretical capacity of 609 mAh g −1 . The cell gains capacity through 100 cycles and has 98 % capacity retention thereafter through 200 cycles, demonstrating stable, long‐term cycling. Raman spectroscopy confirms the proposed mechanism of disulfide bonds breaking to form a S−Li thiolate species upon discharge and reforming upon charge. Coulombic efficiencies near 100 % for every cycle, suggesting the suppression of polysulfide shuttle through the molecular design.