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.