Porous Ionic Network/CNT Composite Separator as a Polysulfide Snaring Shield for High Performance Lithium-Sulfur Battery.

Lithium-sulfur (Li-S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, we report a straightforward electrostatic adsorption strategy based on a crosslinked polyimidazolium separator as a snaring shield of polysulfides, which suppresses undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) were successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. Favorable affinity of the imidazolium ring towards polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li-S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g -1 for PIN/CNT/PP-3) at 0.1 C. This article is protected by copyright. All rights reserved.