Rational design of MoS2 nanosheets decorated on mesoporous hollow carbon spheres as a dual-functional accelerator in sulfur cathode for advanced pouch-type Li-S batteries

• 来源期刊: 能源化学
• 年，卷（期）: 2020,（12）
• 页码范围: 262-271
• 页数: 10页
• 语种: 英文

摘要

Developing sulfur cathodes with high catalytic activity on accelerating the sluggish redox kinetics of lithium polysulfides(LiPSs)and unveiling their mechanisms are pivotal for advanced lithium-sulfur(Li-S)batteries.Herein,MoS2 is verified to reduce the Gibbs free energy for rate-limiting step of sulfur reduc-tion and the dissociation energy of lithium sulfide(Li2S)for the first time employing theoretical calcu-lations.The MoS2 nanosheets coated on mesoporous hollow carbon spheres(MHCS)are then reasonably designed as a sulfur host for high-capacity and long-life Li-S battery,in which MHCS can guarantee the high sulfur loading and fast electron/ion transfer.It is revealed that the shuttle effect is efficiently inhib-ited because of the boosted conversion of LiPSs.As a result,the coin cell based on the MHCS@MOS2-S cathode exhibits stable cycling performance maintaining 735.7 mAh g-1 after 500 cycles at 1.0 C.More importantly,the pouch cell employing the MHCS@MOS2-S cathodes achieves high specific capacity of 1353.2 mAh g-1 and prominent cycle stability that remaining 960.0 mAh g-1 with extraordinary capac-ity retention of 79.8％ at 0.1 C after 170 cycles.Therefore,this work paves a new avenue for developing practical high specific energy and long-life pouch-type Li-S batteries.