Catalytic Mo2C decorated N-doped honeycomb-like carbon network for high stable lithium-sulfur batteries

Abstract

• Honeycomb-like porous hollow carbon network is successfully constructed. • Mo 2 C nanoparticles are embedded into carbon surface with high pyridinic N content. • Lithium sulfur batteries exhibit excellent cycling stability and rate capability. • Mo 2 C enhances the affinity toward polysulfide and accelerates its interconversion. Lithium sulfur (Li-S) batteries hold promise as next-generation high energy density devices due to their high theoretical capacities. However, their commercialization confronts great challenges, in particular the notorious shuttle effect and sluggish kinetics, making it difficult to realize high sulfur loading and cell energy density properties. Herein, we explore the potential of molybdenum carbide (Mo 2 C) as the cathode catalyst to promote the polysulfide conversion. Nanosized Mo 2 C embedded porous carbon network (Mo 2 C@PCN) are prepared through the pyrolysis of molybdenum and chitosan precursor. Both electrochemical performance and theoretical calculations reveal that introducing the Mo 2 C can not only enhance the affinity toward the polysulfide intermediate, but also significantly accelerate the polysulfide interconversion compared with that of the pristine porous carbon network (PCN), thereby endowing the Li-S batteries with excellent cycling stability with a low capacity decay of 0.034 % per cycle over 600 cycles, and superb rate capability of 644 mAh g −1 at 5 A g −1 .