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

• DOI: 10.1021/acsaem.0c00205
• Publication Date: 2020-05-05T18:01:29Z
• Authors: Zhaozhuang Cheng; Yaxiong Wang; Wenjun Zhang; Ming Xu
• Keywords: Polysulfide; Vanadium nitride

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