Development of the hydrogen-X rechargeable fuel cell from the molecular to lab-scale device level
File(s)
Author(s)
Cannon, Christopher
Type
Thesis
Abstract
The most notable examples of electrochemical energy conversion devices are Li-ion batteries and hydrogen fuel cells. In order to improve upon the efficiency, safety and the levelised cost of energy storage, redox-active organic molecules have recently been a prevailing research theme in the field of redox flow batteries. A cell design combining a H2/H+ anode and a single flow battery electrolyte, termed the hydrogen-X rechargeable fuel cell, possesses the desirable characteristic of full reversibility with the use of only abundant energy storage media. This thesis covers the development of electrochemical energy storage from the molecular to cell-level, within the form of a hydrogen-X rechargeable fuel cell. The experimental work in this thesis begins with a study of thioether-centred molecules. Two novel thianthrene derivatives were synthesised and this has led to a better understanding of the structure-property relationship between the addition of substituents and the redox potential. The study of a wider range of amine and N-oxyl centred redox-active molecules was also performed, and operando spectroscopic techniques allowed for further evaluation of the most promising electrolytes. Hydrogen-organic cell chemistries that demonstrated high stability and solubility were up-scaled to a prototypical cell-level stage of development. In the final chapter of experimental work, the hydrogen-methylene blue cell achieved a peak output power density of 238 mW cm-2 at 100% state-of-charge using a 1.0 M electrolyte. However, a H2-N,N,N’,N’-tetramethylbenzidine cell achieved 400 mW cm-2 at just one-tenth of the electrolyte capacity. This thesis therefore presents a rigorous screening process that defines and characterises key properties of interest. As a result, promising rechargeable fuel cell performance in the latter part of this thesis has been demonstrated.
Version
Open Access
Date Issued
2025-04-30
Date Awarded
2025-08-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Kucernak, Anthony
Brandon, Nigel
Klusener, Peter
Sponsor
UK Research and Innovation
Shell
Grant Number
CHIS1200
Publisher Department
Department of Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)