Single-Atom Zinc and Anionic Framework as Janus Separator Coatings for Efficient Inhibition of Lithium Dendrites and Shuttle Effect

The two key problems for the industrialization of Li–S batteries are the dendrite growth of lithium anode and the shuttle effect of lithium polysulfides (LiPSs). Herein, we report the Janus separator prepared by coating anionic Bio-MOF-100 and its derived single-atom zinc catalyst on each side of the Celgard separator. The anionic metal–organic framework (MOF) coating induces the uniform and rapid deposition of lithium ions, while its derived single-atom zinc catalyzes the rapid transformation of LiPSs, thus inhibiting the lithium dendrite and shuttle effect simultaneously. Consequently, compared with other reported Li–S batteries assembled with single-atomic catalysts as separator coatings, our SAZ-AF Janus separator showed stable cyclic performance (0.05% capacity decay rate at 2 C with 1000 cycles), outstanding performance in protecting lithium anode (steady cycle 2800 h at 10 mAh cm–2), and equally excellent cycling performance in Li–SeS2 or Li–Se batteries. Our work provides an effective separator coating design to inhibit shuttle effect and lithium dendrite.