期刊
ELECTROCHIMICA ACTA
卷 403, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2021.139723
关键词
V2O5-x/TiO2 active interface structure; Sulfur-wrapped matrix; High polysulfide adsorption energy; Density functional theory calculation; Shuttle effect
资金
- National Natural Science Foundation of China [22075030]
- Support Program of Distinguished Professor of Liaoning Province [071717002]
- Natural Science Foundation of Liaoning Province [20180510013]
- Program for Liaoning BaiQianWan Talents in University [201797]
- Science and technology general project of Liaoning province education department [LZ2020002, LQ2020009]
In this study, a V2O5-x/TiO2 active interface structure with high polysulfide adsorption energy was designed for lithium-sulfur batteries, which exhibited improved electrochemical performances. The interface showed low electrochemical charge transfer resistance and high lithium-ion transfer efficiency. The sulfur-wrapped cathode material displayed high specific capacities and good cycling stability.
A sulfur composite active material for lithium-sulfur batteries with a highly active interface structure can display excellent electrochemical performances. For this reason, in this paper, we design a type of V2O5-x/TiO2 active interface structure with high polysulfide adsorption energy as a high-performance sulfur-wrapped matrix. Physical property characterization indicates this interface is constructed from circular anatase structure TiO2 and anoxic vanadium oxide structure composed of V4+ and V5+ . After sulfur wrapping, Ti-S and S-S bond structures are produced by chemical and physical adsorption. Density functional theory calculations show that the V2O5-x/TiO2 interface has very high adsorption energy (-5.93 eV) with lithium polysulfide (Li2S6). After sulfur wrapping as a cathode active material, it displays low electrochemical charge transfer resistance (31.89 Omega) and high lithium-ion transfer efficiency (3.50 x 10(-12)). In addition, it has rather high discharge specific capacities of 1466.47, 963.84 and 801.16 mAh.g(-1) at 0.1, 0.2 and 0.5 C, respectively. After 500 cycles, the discharge capacity retention at 0.5 C is up to 76.11% corresponding to 0.048% capacity decay rate per cycle. This is the reason that the V2O5-x/TiO2 active interface has very strong adsorption to polysulfide and can effectively suppress the shuttle effect (Q(low)/Q(high) = 1.44 at 0.2 C). (c) 2021 Elsevier Ltd. All rights reserved.
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