Promoting Li2S Nucleation/Dissolution Kinetics via Multiple Active Sites over TiVCrMoC3Tx Interface.

ABSTRACT

Lithium-sulfur batteries (LSBs) are still limited by some issues such as polysulfides shuttle and lithium dendrites. Recently, the concept "high-entropy" has been considered as the research hotspot and international frontier. Herein, a high entropy MXene (TiVCrMoC3Tx, HE-MXene) doped graphene is designed as the modified coating on commercial separators for LSBs. The HE-MXene affords multiple metal active sites, fast Li+ diffusion rate, and efficient adsorption toward polysulfide intermediates. Furthermore, strong lithophilic property is favorable for uniform Li+ deposition. The combination of in situ characterizations confirms TiVCrMoC3Tx effectively promotes the Li2S nucleation/dissolution kinetics, reduces the Li+ diffusion barrier, and exhibits favorable lithium uniform deposition behavior. This TiVCrMoC3Tx/G@PP provides a high-capacity retention rate after 1000 cycles at 1 C and 2 C, with a capacity decay rate of merely 0.021% and 0.022% per cycle. Surprisingly, the cell operates at a low potential of 48 mV while maintaining at 5 mA cm-2/5 mAh cm-2 for 4000 h. Furthermore, it still maintains a high-capacity retention rate under a high sulfur loading of 4.8/6.4 mg cm-2 and a low E/S ratio of 8.6/7.5 µg mL-1. This work reveals a technical roadmap for simultaneously addressing the cathode and anode challenge, thus achieving potential commercially viable LSBs.