Synergic adsorption and catalytic conversion of polysulfides based on polar Mo2C and pyridinic N for the enhanced electrochemical performance of LieS batteries

As a most promising potential next-generation energy storage system, lithium-sulfur batteries (LieS batteries) received great attention in recent years. However, how to effectively prevent the shuttling effect and accelerate the redox reaction kinetics of polysulfides are still a challenge. Herein, a strategy of using the soft template as a pore-forming agent was proposed to prepare Mo2C/nitrogen-doped carbon hollow microflowers (marked as HeMo2C/NC MFs), which was used as an efficient absorbent and electrocatalyst of polysulfides for LieS batteries. Due to the physical limitations of assembling the special nanosheet into a hollow carbon matrix in the shape of a microflower, the HeMo2C/NC MFs can be used as an appropriate S loading substrate. With the synergistic chemisorption from pyridine N sites and high content polar Mo2C nanoparticles, the as-prepared HeMo2C/NC MFs can provide enhancing adsorption and catalytic conversion for polysulfides. As a result, the HeMo2C/NC/S MFs-based cathode provides a high initial discharge capacity of 1104.8mAh/g at 0.2C. Even at the high rate of 1.0C, the initial capacity of 705.2mAh/g still shows good electrochemical performance, and in 1000 cycles, the average capacity decay rate is only 0.016%, with supercycle stability. This article provided a new strategy for a novel viewpoint for the reasonable design of conductive and polar materials for efficient and durable LieS batteries. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study proposed a strategy of using a soft template to prepare Mo2C/nitrogen-doped carbon hollow microflowers, which serve as efficient absorbents and electrocatalysts for polysulfides in LieS batteries. The fabricated HeMo2C/NC MFs exhibit enhanced adsorption and catalytic conversion for polysulfides, leading to high initial discharge capacity and good electrochemical performance. The article provides a novel viewpoint and strategy for the reasonable design of materials for efficient and durable LieS batteries.