title: Performance-Enhancing Asymmetric Separator for Lithium-Sulfur Batteries.
abstract: Asymmetric separators with polysulfide barrier properties consisting of porous polypropylene grafted with styrenesulfonate (PP-g-PLiSS) were characterized in lithium-sulfur cells to assess their practical applicability. Galvanostatic cycling at different C-rates with and without an electrolyte additive and cyclic voltammetry were used to probe the electrochemical performance of the cells with the PP-g-PLiSS separators and to compare it with the performance of the cells utilizing state-of-the-art separator, Celgard 2400. Overall, it was found that regardless of the applied cycling rate, the use of the grafted separators greatly enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site (-SO3(-)) concentration at and near the surface of the separator was found to be essential to effectively suppress the polysulfide shuttle without sacrificing the Li-ion mobility through the separator and to improve the practical specific charge of the cell.
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Conder
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Antoni
authors.initials: A
authors.lastname: Forner-Cuenca
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Elisabeth Müller
authors.initials: EM
authors.lastname: Gubler
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Gubler
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Petr
authors.initials: P
authors.lastname: Novák
authors.affiliation: Electrochemistry Laboratory and ‡Laboratory of Biomolecular Research, Paul Scherrer Institute , CH-5232 Villigen, Switzerland.
authors.forename: Sigita
authors.initials: S
authors.lastname: Trabesinger
keywords: Li−S battery; grafted separators; polysulfide rejection; polysulfide shuttle control; separators