title: Exploring 3D microstructural evolution in Li-Sulfur battery electrodes using in-situ X-ray tomography.
abstract: Lithium sulfur (Li-S) batteries offer higher theoretical specific capacity, lower cost and enhanced safety compared to current Li-ion battery technology. However, the multiple reactions and phase changes in the sulfur conversion cathode result in highly complex phenomena that significantly impact cycling life. For the first time to the authors' knowledge, a multi-scale 3D in-situ tomography approach is used to characterize morphological parameters and track microstructural evolution of the sulfur cathode across multiple charge cycles. Here we show the uneven distribution of the sulfur phase fraction within the electrode thickness as a function of charge cycles, suggesting significant mass transport limitations within thick-film sulfur cathodes. Furthermore, we report a shift towards larger particle sizes and a decrease in volume specific surface area with cycling, suggesting sulfur agglomeration. Finally, we demonstrate the nano-scopic length-scale required for the features of the carbon binder domain to become discernible, confirming the need for future work on in-situ nano-tomography. We anticipate that X-ray tomography will be a powerful tool for optimization of electrode structures for Li-S batteries.
authors.affiliation: Electrochemical Innovation Lab, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE, UK.|Nazarbayev University, National Laboratory Astana, 53 Kabanbay Batyr Ave., Astana, 010000, Kazakhstan.
authors.forename: Assiya
authors.initials: A
authors.lastname: Yermukhambetova
authors.affiliation: Electrochemical Innovation Lab, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Chun
authors.initials: C
authors.lastname: Tan
authors.affiliation: Electrochemical Innovation Lab, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Sohrab R
authors.initials: SR
authors.lastname: Daemi
authors.affiliation: Nazarbayev University, National Laboratory Astana, 53 Kabanbay Batyr Ave., Astana, 010000, Kazakhstan.|Institute of Batteries LLC, 53 Kabanbay Batyr Ave., Astana, 010000, Kazakhstan.
authors.forename: Zhumabay
authors.initials: Z
authors.lastname: Bakenov
authors.affiliation: Department of Chemistry, Christopher Ingold Building, UCL, 20 Gordon Street, London WC1H 0AJ, UK.
authors.forename: Jawwad A
authors.initials: JA
authors.lastname: Darr
authors.affiliation: Electrochemical Innovation Lab, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Daniel J L
authors.initials: DJ
authors.lastname: Brett
authors.affiliation: Electrochemical Innovation Lab, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE, UK.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Shearing