Boosting Polysulfide Conversion in Lithium-Sulfur Batteries by Cobalt-Doped Vanadium Nitride Microflowers

被引：51

作者：

Cheng, Zhaozhuang ^{[1
]}

Wang, Yaxiong ^{[1
]}

Zhang, Wenjun ^{[1
]}

Xu, Ming ^{[1
]}

机构：

[1] Huazhong Univ Sci & Technol, Sch Mat Sci & Engn, State Key Lab Mat Proc & Die & Mould Technol, Wuhan 430074, Peoples R China

来源：

ACS APPLIED ENERGY MATERIALS | 2020年 / 3卷 / 05期

基金：

中国国家自然科学基金;

关键词：

Li-S batteries; vanadium nitride; Co doping; polysulfide; electronic structure modulation; microflower structure; TRANSITION-METAL NITRIDES; CARBON NANOTUBES; CATALYSTS; CATHODE; SURFACE; LIFE; ADSORPTION; REDUCTION; BINDING; SITES;

D O I：

10.1021/acsaem.0c00205

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 shuttle effect of polysulfide (Li2Sn, 2 < n <= 8) and the sluggish reaction kinetics seriously hinder the development of lithium-sulfur (Li-S) batteries. Regulating the electronic structure of substrate materials could be an effective strategy to further modulate surface polysulfide adsorption and interface electron transfer for advanced Li-S batteries. Herein, a cobalt-doped vanadium nitride (Co-VN) microflower hierarchical structure with a 5% Co/V ratio was synthesized as a substrate material. Theoretical calculation indicated that the polysulfide adsorption energy of Co-VN (-5.04 eV) was enhanced compared to that of VN (-4.14 eV). Electrochemical experiments verified that the polarization and internal resistance of VN were lowed after Co doping. Electrochemical tests showed that the cyclic stability of the Co-VN/sulfur (Co-VN/S) composite cathode was greatly improved compared to the undoped one, achieving an impressive initial capacity of 706 mAh g(-1) at 2.0 C and that the fading rate of discharge capacity over 500 cycles was only 0.034% per cycle. A discharge capacity of 873 mAh g(-1) under remarkable sulfur loading (4.42 mg cm(-2)) was also achieved with a capacity decay rate of 0.028% per cycle over 100 cycles.

引用

页码：4523 / 4530

页数：8

共 53 条

[21] Nitrogen-Doped Carbon Nanotube Forests Planted on Cobalt Nanoflowers as Polysulfide Mediator for Ultralow Self-Discharge and High Areal-Capacity Lithium-Sulfur Batteries [J].