Operando characterisation techniques for graphene-based lithium-sulfur batteries
type: CreativeWork
description: Lithium-sulfur (Li-S) batteries have the potential to enable high-gravimetric capacity, low-cost energy storage, but their widespread implementation is presently limited by their rapid capacity degradation due to irreversible loss of electrical connectivity with their active material. Electrically conductive cathodic host matrices, with a porous structure tuned to retain the soluble sulfur and polysulfides (PS) formed during cycling, are an active research area, with graphene-related materials (GRMs) of particular interest due to their compatibility with high-throughput manufacturing processes. This thesis presents a meta-analysis of recent literature on Li-S host matrices, for which a graphical user interface was developed to collate reported parameters and directly link them to attained cell capacities. This meta-analysis highlights the wide array of approaches and parameter combinations reported in the literature, and the corresponding lack of convergence in cell performance to date. A novel method of synthesising sulfur/ carbon composites is presented, entailing co-high pressure homogenization (co-HPH) of graphite and sulfur, and is evaluated against a conventional thermal-infiltration synthesis method. A new technique for analysing galvanostatic cycling data is employed to compare their electrochemical performance, suggesting the more homogenous novel composites undergo gradual dissolution of sulfur over multiple cycles compared to the dissolution of sulfur within ca. 20 cycles in thermally-infiltrated composites. This thesis also reports an attempt to characterise the morphology of these composites using X-ray tomography, with the key outcome being a novel method for labelling and segmenting heterogeneous tomography data using Isomap-based dimensionality reduction. Spatially-resolved operando Raman spectroscopy was applied to acquire 2d maps of the sulfur and PS in electrodes undergoing cycling, and monitor the (re-)distribution of active material in electrode…
abstract: Lithium-sulfur (Li-S) batteries have the potential to enable high-gravimetric capacity, low-cost energy storage, but their widespread implementation is presently limited by their rapid capacity degradation due to irreversible loss of electrical connectivity with their active material. Electrically conductive cathodic host matrices, with a porous structure tuned to retain the soluble sulfur and polysulfides (PS) formed during cycling, are an active research area, with graphene-related materials (GRMs) of particular interest due to their compatibility with high-throughput manufacturing processes. This thesis presents a meta-analysis of recent literature on Li-S host matrices, for which a graphical user interface was developed to collate reported parameters and directly link them to attained cell capacities. This meta-analysis highlights the wide array of approaches and parameter combinations reported in the literature, and the corresponding lack of convergence in cell performance to date. A novel method of synthesising sulfur/ carbon composites is presented, entailing co-high pressure homogenization (co-HPH) of graphite and sulfur, and is evaluated against a conventional thermal-infiltration synthesis method. A new technique for analysing galvanostatic cycling data is employed to compare their electrochemical performance, suggesting the more homogenous novel composites undergo gradual dissolution of sulfur over multiple cycles compared to the dissolution of sulfur within ca. 20 cycles in thermally-infiltrated composites. This thesis also reports an attempt to characterise the morphology of these composites using X-ray tomography, with the key outcome being a novel method for labelling and segmenting heterogeneous tomography data using Isomap-based dimensionality reduction. Spatially-resolved operando Raman spectroscopy was applied to acquire 2d maps of the sulfur and PS in electrodes undergoing cycling, and monitor the (re-)distribution of active material in electrode…
author: Bird, Lauren
language: eng
keywords: Battery, Graphene, Lithium-sulfur, Meta-analysis, Principal component analysis, Raman, Synchrotron X-ray CT
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/75f8e39f-45d1-4025-af74-07907ed450e5/download
license: https://creativecommons.org/licenses/by/4.0/
date published: 2024-03-13
date modified: 2026-07-22T22:24:31Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.111603