Ionic Conductive Binder for High Volumetric Energy Density Lithium-Sulfur Batteries

Porous sulfur cathodes in lithium-sulfur batteries (LSBs) enhance sulfur utilization but reduce volumetric energy density (VED), while compact cathodes improve VED at the cost of utilization and electrochemical kinetics. To address these limitations, we prepared an ionic conductive binder (PSL) by adding lithium bis(trifluoromethanesulfonyl)imide as a charge carrier to the PVDF and adding succinonitrile to reduce the crystallinity of PVDF. As a result, the PSL cathode demonstrated improved reaction kinetics and sulfur utilization compared with the PVDF cathode. Notably, the PSL cathode achieves a higher volumetric capacity of 608.0 Ah L^-1, which is 12 times that of the PVDF cathode (51.6 Ah L^-1). Furthermore, a low-porosity (26.0%) PSL cathode enables a pouch cell to deliver a VED of 827.8 Wh L^-1 (including packaging) with a total capacity of 1.3-Ah. This strategy provides initial design insights relevant to the development of high-energy-density LSBs.