Activation of Oxygen‐Stabilized Sulfur for Li and Na Batteries. (10th December 2015)

• Record Type: Journal Article
• Authors: Luo, Chao; Zhu, Yujie; Borodin, Oleg; Gao, Tao; Fan, Xiulin; Xu, Yunhua; Xu, Kang; Wang, Chunsheng
• Is Part Of: Advanced functional materials. Volume 26:Number 5(2016)
• Page Start: 745
• Page End: 752
• Publication Date: 2015-12-10
• Subjects: composites -- electrochemical activation -- lithium sulfur batteries -- oxygen stabilized carbon/sulfur -- oxygen–sulfur bonds -- sodium sulfur batteries; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201503918
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : 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. Abstract : Oxygen‐stabilized C/S composites are synthesized by annealing a mixture of sulfur and perylene‐3, 4, 9, 10‐tetracarboxylic dianhydride in a sealed vacuum glass tube. It is discovered that extra reversible capacity can be obtained if prelithiating the composite at low potentials. The oxygen‐stabilized C/S composites make promising sulfur‐cathode materials for both Li–S and Na–S batteries.