All-purpose redox-active metal-organic frameworks as both cathodic and anodic host materials for advanced lithium-sulfur batteries

Abstract

Multifunctional metal-organic frameworks (MOFs) hold great potential in addressing challenges in energy storage devices by offering customizable guest-host interactions. Herein, we integrated Lewis acidic metal clusters (M = Zr⁴⁺, Hf⁴⁺, and Th⁴⁺) and redox-active Ni-bis(dithiolene) units (NiS₄) into a series of bifunctional MOFs, which serve as both cathodic and anodic host materials for lithium-sulfur (Li-S) batteries. Through systematic control experiments and density functional theory simulations, we elucidate the crucial roles of metal clusters and NiS₄ units in achieving efficient adsorption and rapid electrocatalytic conversion of polysulfides on the cathode and promoting uniform Li nucleation for enhanced cycling stability on the anode. Optimizing the MOF design resulted in advanced Li-S batteries, exhibiting remarkable capacity retention (81.5%) and an ultrahigh Coulombic efficiency (99.5%) after 800 cycles. This study highlights the potential of multifunctional MOFs in simultaneously overcoming the bottlenecks faced by the S cathode and Li anode.