Synergistic engineering of structural and electronic regulation in necklace-like UiO-66/ACNT structure toward lithium-sulfur batteries with fast polysulfide redox

Although UiO-66-based metal–organic framework (MOF) composites have been widely applied in the entrapment and catalytic effect toward lithium polysulfides (LiPSs), the synergistic engineering of structural and electronic regulation strategy has not been carefully considered. Herein, we optimize the internal cluster structure, rational regulate the size of UiO-66, and design the necklace-like structure composed of UiO-66 nanoparticles and acid-treated carbon nanotube (UiO-66/ACNT) through simple hydrothermal reaction and thermal treatment strategy. According to experiments and density universal function theory calculations, the improved UiO-66/ACNT architecture effectively provides more polarity to capture polysulfides via exposing more active sites and effectively delivers electrocatalytic activity of polysulfide conversion. Furthermore, systematic electrocatalytic kinetics, in situ Raman spectroscopy and in-situ impedance analysis indicate the functional separator can inhibit the shuttling effect, and catalyze the conversion of lithium polysulfide. As a result, Li-S batteries with functional separators exhibit excellent electrochemical performance (low fading rate over 1000 cycles of 0.06 % per cycle at 1C, high areal capacity of 4.01 mAh cm−2 at 0.2C). This work offers insight into the rational design of UiO-66-based metal–organic frameworks (MOFs) through synergistic engineering for high-performance Li-S batteries.