MOF-related electrocatalysts for sulfur reduction/evolution reactions: Composition modulation, structure design, and mechanism research

The electrocatalytic sulfur reduction reaction (SRR) and sulfur evolution reaction (SER), two fundamental multistep conversion processes in lithium–sulfur batteries (LSBs), are root-cause solutions to overcome sluggish redox kinetics and the polysulfide shuttling effect. Metal–organic framework (MOF) electrocatalysts have emerged as good platforms for catalyzing SRR and SER, but their catalytic performance is challenged by poor electrical conductivity and limited chemical stability. Functionalized MOFs and their hybrids may be beneficial for stabilizing and improving the desired catalytic properties to achieve high-performance LSBs. This review provides a detailed overview of engineering principles for improving the activity, selectivity, and stability of MOF-related electrocatalysts via composition modulation and nanostructure design as well as hybrid assembly. It presents and discusses the various advances achieved by using in situ characterization techniques, simulations, and theoretical calculations to reveal the dynamic evolution of MOF-related electrocatalysts, enabling an in-depth understanding of the catalysis mechanism at the molecular/atomic level. Lastly, prospects and possible research directions for MOF-related sulfur electrocatalysts are proposed.