Polysulfide-shuttle has been a critical concern for the advancement of lithium-sulfur (Li-S) batteries. Celgard membranes that are generally used in Li-S batteries exhibit a porous structure with a pore dimension generally on the micrometer scale. During cell operation, soluble lithium polysulfide species can easily migrate from the cathode through the porous separator and react with the lithium-metal anode. Such an unexpected chemical reaction induces a cascade of negative effects on the overall performance of Li-S batteries. Use of ion-selective membranes with reduced pore size provides a promising approach to suppress the migration of polysulfide species. In this study, a membrane based on a polymer with intrinsic nanoporosity (PIN) with a pore size of <1.0 nm is explored as a separator in Li-S batteries to mitigate the polysulfide-shuttle problem. The PIN membrane exhibits a unique structure with pore dimensions of less than 1.0 nm, which allows the transport of Li-ions, but effectively blocks the migration of dissolved polysulfides. As a result, the cycling performance of Li-S batteries is significantly improved. In addition to demonstrating a PIN-membrane Li-S battery, the structural characteristics of the PIN membrane have been characterized by a series of experimental methodologies and molecular dynamics (MD) simulations.
Bibliographical noteFunding Information:
The materials synthesis, characterization, and electrochemical analysis work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0005397 . The MD simulation work was supported by the Robert A. Welch Foundation ( F-1535 ) and the HPC resources were provided by Texas Advanced Computing Center (TACC). The molecular weight determination work was supported by the Robert A. Welch Foundation ( F-1904 ). S. F. thanks the China Scholarship Council (No. 201506170095 ) for the financial support.
© 2018 Elsevier Ltd
- Electrochemical performance
- Lithium-sulfur batteries
- Molecular dynamics simulation
- Polymer membrane
- Polysulfide shuttle