Rational design of a polysulfide catholyte electrocatalyst by interfacial engineering based on novel MoS2/MoN heterostructures for superior room-temperature Na–S batteries

Abstract

A suitable electrocatalyst plays an essential role in room-temperature Na–S (RT/Na–S) batteries owing to the more severe dissolution of polysulfides and sluggish kinetics of the conversion of polysulfides during charging and discharging processes. In this study, a novel MoS2/MoN heterostructure synthesized via NH3 annealing was introduced as an electrocatalyst into RT/Na–S batteries to promote the evolution of polysulfides in the catholyte with an initial specific capacity of 703 mA h g−1 and retains 392 mA h g−1 after 300 cycles. The density-functional theory (DFT) calculations, ex-situ XPS and Raman spectra were utilized to reveal moderate anchoring and the fast redox kinetics of polysulfides, significantly enhancing the cycling performance and electrochemical performance of the RT-Na/S batteries when compared with those of the RT-Na/S batteries containing pure MoS2 or MoN as the catalyst. The work provides a new strategy for guiding the design of high‐performance catalysts with manipulated chemical components and optimized adsorption ability.