In situ preparation of chromium carbide–modified carbon nanofibers as functional electrocatalyst for polysulfide reduction in lithium/sulfur batteries

• Published in: Ionics 2022-04, Vol.28 (4), p.1701-1711
• Main Authors: Li, Tianbao, Ma, Chao, Li, Yangyang, Tu, Feiyue, Jiao, Can, Li, Zhongliang, Yao, Shanshan
• Format: Article
• Language: English
• Subjects: Ammonium compounds; Carbon fibers; Catalytic converters; Chemistry; Chemistry and Materials Science; Chromium carbide; Condensed Matter Physics; Conversion; Diffusion rate; Electrocatalysts; Electrochemistry; Electron transfer; Energy Storage; Lithium; Lithium ions; Lithium sulfur batteries; Nanofibers; Nanoparticles; Optical and Electronic Materials; Original Paper; Polysulfides; Reduction; Renewable and Green Energy
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-021-04431-0

Lithium polysulfide shuttle effect and their sluggish redox kinetics have seriously affected the development of lithium/sulfur (Li/S) batteries. To solve these issues, free-standing chromium carbide–modified carbon nanofiber (Cr 3 C 2 /CNF) electrocatalytic membrane for Li/S batteries is in situ synthesized by solution impregnation method with ammonium chromate ((NH 4 ) 2 CrO 4 ) and carbothermal reduction technology. CNFs provide fast pathways for electron transfer and lithium ions diffusion, promote the catalytic conversion, and restrain the shuttle effect. Cr 3 C 2 nanoparticles in situ grow on the surface of the CNFs and play a role in adsorbing and catalyzing the conversion of lithium polysulfides. Due to advantage structure, Cr 3 C 2 /CNFs@Li 2 S 6 electrode (sulfur loading: 4.74 mg) exhibits excelled cycling stability (initial discharge capacity: 977 mAh g −1 ; 828 mAh g −1 at 0.2 C over 300 cycles). Even at high sulfur loading of 7.11 mg, the composite electrode also shows high capacity (6.11 mAh). The above results provide an effective route for high performance of Li/S batteries.