Characterising Electrolyte Interactions with Carbon Anodes for Sodium Ion Batteries
type: CreativeWork
description: Battery technologies are of fundamental importance to the modern world and the current development of electric vehicles, as well as grid storage of renewable energy, is placing an increased demand on Li-ion batteries (LIBs). Na-ion batteries (NIBs) are seen as a promising alternative to LIBs due to their lower cost and environmental impact. As Na has a similar chemistry to Li, the transfer of battery technology is also expected to be straightforward, but this is not always the case. For example, graphite is the most common anode for LIBs; however, it is not able to accommodate Na under normal circumstances. Disordered hard carbons are often used instead, this is despite their structure and sodiation mechanism not being fully understood. The choice of electrolyte for a battery is critical and if certain electrolyte solvents such as diglyme are used, co-intercalation of Na into graphite occurs. In Chapter 3, the interactions between diglyme molecules and graphite are investigated using various techniques, including nuclear magnetic resonance spectroscopy and thermogravimetric analysis. Similar techniques were then also used to provide evidence that diglyme also co-intercalates into the disordered hard carbons that are normally used as anodes, albeit to a lesser extent than in graphite. Chapter 4 sets out to probe the dynamics of diglyme co-intercalated into hard carbon using 2H NMR and simulations, and then use the dynamics of diglyme as an indirect probe for the structure of hard carbon. It was found that the motion of diglyme can be described by simulating a molecular rotation of diglyme with a lognormal distribution of rotation rates, which is indicative of the range of different sites that Na-diglyme complexes can occupy in hard carbon. By probing hard carbon at different states of charge, it was also found that the motion of diglyme increased on sodiation, indicating that hard carbon expands as Na intercalates into the structure, giving diglyme more space to move…
abstract: Battery technologies are of fundamental importance to the modern world and the current development of electric vehicles, as well as grid storage of renewable energy, is placing an increased demand on Li-ion batteries (LIBs). Na-ion batteries (NIBs) are seen as a promising alternative to LIBs due to their lower cost and environmental impact. As Na has a similar chemistry to Li, the transfer of battery technology is also expected to be straightforward, but this is not always the case. For example, graphite is the most common anode for LIBs; however, it is not able to accommodate Na under normal circumstances. Disordered hard carbons are often used instead, this is despite their structure and sodiation mechanism not being fully understood. The choice of electrolyte for a battery is critical and if certain electrolyte solvents such as diglyme are used, co-intercalation of Na into graphite occurs. In Chapter 3, the interactions between diglyme molecules and graphite are investigated using various techniques, including nuclear magnetic resonance spectroscopy and thermogravimetric analysis. Similar techniques were then also used to provide evidence that diglyme also co-intercalates into the disordered hard carbons that are normally used as anodes, albeit to a lesser extent than in graphite. Chapter 4 sets out to probe the dynamics of diglyme co-intercalated into hard carbon using 2H NMR and simulations, and then use the dynamics of diglyme as an indirect probe for the structure of hard carbon. It was found that the motion of diglyme can be described by simulating a molecular rotation of diglyme with a lognormal distribution of rotation rates, which is indicative of the range of different sites that Na-diglyme complexes can occupy in hard carbon. By probing hard carbon at different states of charge, it was also found that the motion of diglyme increased on sodiation, indicating that hard carbon expands as Na intercalates into the structure, giving diglyme more space to move…
author: Smith, Thomas
language: eng
keywords: Sodium Ion Battery, Electrolyte, Anode, Electrochemistry, NMR
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2022-01-31
date modified: 2026-07-22T22:24:28Z
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.86259