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

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. [Display omitted] •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.•The DFT calculations, ex situ XPS and Raman spectrum were utilized to reveal moderate anchoring and fast redox kinetics of polysulfides.•The work provides a new strategy for guiding the design of high‐performance catalysts with manipulated chemical components and optimized adsorption ability.