Chemically etched CeO2-x nanorods with abundant surface defects as effective cathode additive for trapping lithium polysulfides in Li-S batteries

被引:24
|
作者
Wei, Zhen [1 ]
Wang, Ruigang [1 ]
机构
[1] Univ Alabama, Dept Met & Mat Engn, Tuscaloosa, AL 35487 USA
基金
美国国家科学基金会;
关键词
Li-S battery; Shuttle effect; Host materials; CeO2; nanorods; Oxygen vacancies; NaBH; 4; treatment; CO OXIDATION; SUPPORT STRUCTURE; SIO2; NANOSPHERES; OXYGEN VACANCY; SULFUR; PERFORMANCE; CARBON; GRAPHENE; CONVERSION; NANOSHEETS;
D O I
10.1016/j.jcis.2022.01.165
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The commercialization of Li-S batteries has been seriously hindered by the notorious polysulfides shuttling and sluggish redox kinetics. To effectively address these technical issues, in this work, oxygen deficient CeO2-x & nbsp;nanorods (NR) decorated on free-standing carbon cloth (CeO2-x NR@CC) were used as a promising dual-functional cathode host material to enhance the electrochemical and cycling performance of Li-S batteries. The oxygen-deficient CeO2-x NR were prepared in a facile processing route by tuning the surface structures of pristine CeO2 NR in strong reducing NaBH4 solution. In contrast to the pristine CeO2NR@CC control sample, chemically etched CeO2-x & nbsp;NR@CC with abundant implanted oxygen vacancies effectively trapped the polysulfides and dramatically accelerated electron charge transfer, leading to faster redox kinetics. The main working mechanism of CeO2-x NR@CC on the improved electrochemical performance was attributed to chemical binding effect on trapping lithium polysulfides and even promoting the conversion of polysulfides, thanks to reversible Ce3+/Ce(4+& nbsp;)transformation, oxygen vacancies, and other surface defects. Hence, the CeO2-x & nbsp;NR@CC electrode delivered an outstanding initial capacity of 1358 mAh g(-1) at 0.2C for the 1st cycle and a superb sulfur utilization of 81%, compared to an initial capacity of 1176 mAh g(-1) at 0.2C and a sulfur utilization of 70% for the CeO2 NR@CC electrode. The improved electrochemical performances of the CeO2-x NR@CC electrode can be mainly attributed to the successful adsorption of more dissolvable polysulfides by the dual-functional cathode host materials that combine the physical confinement of conductive CC and the chemical binding of CeO2-x NR with ample surface defects. (C) 2022 Elsevier Inc. All rights reserved.
引用
收藏
页码:527 / 542
页数:16
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