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Activation of Oxygen‐Stabilized Sulfur for Li and Na Batteries
Author(s) -
Luo Chao,
Zhu Yujie,
Borodin Oleg,
Gao Tao,
Fan Xiulin,
Xu Yunhua,
Xu Kang,
Wang Chunsheng
Publication year - 2016
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201503918
Subject(s) - polysulfide , sulfur , oxygen , electrochemistry , cathode , materials science , anode , chemical engineering , carbon fibers , composite number , inorganic chemistry , electrode , chemistry , electrolyte , composite material , organic chemistry , metallurgy , engineering
The sulfur‐based cathode materials suffer severely from poor cycling stability and low utilization, incurred by their stepwise reaction mechanism that generates polysulfide intermediates and the subsequent irreversible losses. In this work, those issues are significantly relieved by entrapping sulfur species in carbon host rich in oxygen functionalities. Sulfur species in such C/S composite are highly stabilized by their interaction with oxygen, and can deliver a reversible capacity of 508 mAh/(g of S) for 2000 cycles when coupled with Li, representing the best cycling stability up to date. More interestingly, extra capacity can be accessed by simply prelithiating the oxygen‐stabilized C/S composites down to 0.6 V for a few cycles, which enables a high capacity of 1621 mAh/(g of S) that eventually stabilizes at 820 mAh/(g of S) for 600 cycles. The mechanism for this electrochemical activation process is investigated with both spectroscopic and electrochemical techniques, which reveal that the inactive sulfur bonded to oxygen is liberated in the initial deep lithiation precycles and becomes electrochemically active. The oxygen‐stabilized sulfur can also be coupled with Na anode to form Na/S cell, confirming that the formation of S−O interaction in C/S composite generates promising sulfur‐based cathode materials for Li–S and Na–S batteries.