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

Vladimir P. Oleshko, Andrew A. Herzing, Christopher L. Soles, Jared J. Griebel, Woo J. Chung, Adam G. Simmonds, Dong-Chul Pyun

Research output: Contribution to journalArticle

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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; (c) concomitant improvements in the stability with preserved meso- and nanoscale porosities required for efficient charge transport.

Original languageEnglish (US)
Pages (from-to)1198-1221
Number of pages24
JournalMicroscopy and Microanalysis
Volume22
Issue number6
DOIs
Publication statusPublished - Dec 1 2016

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Keywords

  • EDXS
  • EELS
  • Li-S batteries
  • S(T)EM
  • tomography

ASJC Scopus subject areas

  • Instrumentation

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