FeCo alloy catalysts promoting polysulfide conversion for advanced lithium-sulfur batteries

• 作者: Hongyi Li Linfeng Fei Longlong Shu Rong Zhang Shenglan Yu Yong Li Yongyi Zhang Yu Wang
• 来源期刊: 能源化学
• 年，卷（期）: 2020,（10）
• 页码范围: 339-347
• 页数: 9页
• 语种: 英文

摘要

Lithium sulfur batteries (LSBs) draw extensive interest because of the ultra-high capacity and low material cost.However,the sluggish lithium polysulfides (LIPSs) conversion processes are detrimental to cycle stability and rate capability,inhibiting the commercial application of LSBs.Here we present the well-designed FeCo alloy catalysts anchored on porous carbon (FeCo-C) as sulfur host to improve the electrochemical performance by accelerating the conversion reactions.The FeCo alloy demonstrates high catalytic effect and strong adsorption capability of LIPSs,in which potential polarization can be greatly decreased and "shuttle effects" can be largely avoided.As a result,the obtained S/FeCo-C composites show an initial specific capacity of 791.9 mAh g-1 at a large current density of 2 C and maintain 502.5 mAh g-1 even after 500 cycles.Moreover,720 mAh g-1 (corresponding to 70％ retention) can be achieved after 100 cycles at 0.2 C with a high sulfur content of 80 wt％,enabling high sulfur utilization.This work not only provides a new insight to investigate the conversion kinetics of LiPSs,but also opens up a new avenue for advanced lithium sulfur batteries.