| Autor: |
Lee DJ; Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States., Yu X; Program of Materials Science, University of California, San Diego, La Jolla, California 92093, United States., Sikma RE; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States., Li M; Program of Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States., Cohen SM; Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States.; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States., Cai G; Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States., Chen Z; Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States.; Program of Materials Science, University of California, San Diego, La Jolla, California 92093, United States.; Program of Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States.; Sustainable Power and Energy Center, University of California, San Diego, La Jolla, California 92093, United States. |
| Abstrakt: |
Metal-organic framework (MOF)-based membranes have received significant attention as separators for lithium-sulfur (Li-S) batteries because of their high porosities, well-defined and tailored structures, and other tunable features that are desirable for preventing the "shuttle effect" of soluble polysulfides. Because of the insulating nature of most MOFs, composite membranes are generally constructed by a combination of MOFs and electron-conductive materials. In this work, we examine the property-performance relation between MOF-based separators and Li-S batteries by systematically adjusting the electrical conductivity, thickness, and mass loading of the MOF-based composite. Beyond the commonly referenced trapping or blocking ability of MOFs toward polysulfides, we find that by fixing the thickness of the MOF-based composite coating layer (∼40 μm) on a Celgard membrane, the electrical conductivity of the MOF composite layer is of paramount importance compared with the physical/chemical trapping ability of polysulfides. However, the trapping ability of MOFs becomes indispensable when the thickness of the composite layer is small (e.g., ∼20 μm), indicating the synergetic effects of the adsorption and conversion capabilities of the thin composite layer. This work suggests the importance of a holistic design consideration for a MOF-based membrane for long-life and high-energy-density Li-S batteries. |
