Uniformly distributed 1T/2H-MoS2 nanosheets integrated by melamine foam-templated 3D graphene aerogels as efficient polysulfides trappers and catalysts in lithium-sulfur batteries

Abstract

• MF-GA-MoS 2 composite acts as a new separator-modified material. • 1T/2H-MoS 2 nanosheets were integrated onto the 3D graphene aerogel using melamine foam as template. • GA framework acts a conductive network and physical barrier of LiPSs. • 1T/2H-MoS 2 nanosheets can produce strong chemossorption to LiPSs and promote their conversion to Li 2 S 2 /Li 2 S. Lithium-sulfur (Li-S) batteries are regarded as one of the next-generation batteries because of their low cost and higher energy density than Li-ion batteries. However, the rapid capacity fading due to the shuttling effect of long-chain lithium polysulfides (LiPSs) between electrodes and sluggish redox kinetics remain a big hindrance in practical applications. Herein, three-dimensional nitrogen-doped graphene aerogel (GA) with uniformly distributed and defect-rich 1T/2H-MoS 2 nanosheets has been developed by adding melamine foam (MF) as the hard template. The resultant MF-GA-MoS 2 composites have strong electron transfer capabilities and rich catalytic activity sites that can adsorb and catalyze the conversion of LiPSs to Li 2 S 2 /Li 2 S, thus reducing the shuttle effect to improve the performance of Li-S batteries. Li-S batteries with the defect-rich MF-GA-MoS 2 composites modified separator exhibit amazing initial discharge capacity of 1323 mAh g −1 at 0.2C, high ratio capacity of 718 mAh g −1 at 1C after 400 cycles, and low decay rate of 0.0485% per lap after 800 cycles at 3C. This work provides a novel strategy for the development of separator modified materials with high adsorption and catalytic properties in Li-S batteries.