title: Analytical Multimode Scanning and Transmission Electron Imaging and Tomography of Multiscale Structural Architectures of Sulfur Copolymer-Based Composite Cathodes for Next-Generation High-Energy Density Li-S Batteries.
abstract: Poly[sulfur-random-(1,3-diisopropenylbenzene)] copolymers synthesized via inverse vulcanization represent an emerging class of electrochemically active polymers recently used in cathodes for Li-S batteries, capable of realizing enhanced capacity retention (1,005 mAh/g at 100 cycles) and lifetimes of over 500 cycles. The composite cathodes are organized in complex hierarchical three-dimensional (3D) architectures, which contain several components and are challenging to understand and characterize using any single technique. Here, multimode analytical scanning and transmission electron microscopies and energy-dispersive X-ray/electron energy-loss spectroscopies coupled with multivariate statistical analysis and tomography were applied to explore origins of the cathode-enhanced capacity retention. The surface topography, morphology, bonding, and compositions of the cathodes created by combining sulfur copolymers with varying 1,3-diisopropenylbenzene content and conductive carbons have been investigated at multiple scales in relation to the electrochemical performance and physico-mechanical stability. We demonstrate that replacing the elemental sulfur with organosulfur copolymers improves the compositional homogeneity and compatibility between carbons and sulfur-containing domains down to sub-5 nm length scales resulting in (a) intimate wetting of nanocarbons by the copolymers at interfaces; (b) the creation of 3D percolation networks of conductive pathways involving graphitic-like outer shells of aggregated carbons;
authors.affiliation: 1Materials Science and Engineering Division,Material Measurement Laboratory,National Institute of Standards and Technology,Gaithersburg,MD 20899,USA.
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Oleshko
authors.affiliation: 2Materials Measurement Science Division,Material Measurement Laboratory,National Institute of Standards and Technology,Gaithersburg,MD 20899,USA.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Herzing
authors.affiliation: 1Materials Science and Engineering Division,Material Measurement Laboratory,National Institute of Standards and Technology,Gaithersburg,MD 20899,USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Soles
authors.affiliation: 3Department of Chemistry & Biochemistry,University of Arizona,Tucson,AZ 85721,USA.
authors.forename: Jared J
authors.initials: JJ
authors.lastname: Griebel
authors.affiliation: 3Department of Chemistry & Biochemistry,University of Arizona,Tucson,AZ 85721,USA.
authors.forename: Woo J
authors.initials: WJ
authors.lastname: Chung
authors.affiliation: 3Department of Chemistry & Biochemistry,University of Arizona,Tucson,AZ 85721,USA.
authors.forename: Adam G
authors.initials: AG
authors.lastname: Simmonds
authors.affiliation: 3Department of Chemistry & Biochemistry,University of Arizona,Tucson,AZ 85721,USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Pyun
keywords: EDXS; EELS; Li–S batteries; S(T)EM; tomography