We just published a fundamental investigation of selenium structure at different length scales and how it affects the electrochemical reactions achieved in aluminium-selenium batteries. To achieve a full 6-electron capacity of selenium electrodes in aluminium batteries, it is imperative that the Se(0) to Se(–II) is attainable as well as the Se(0) to Se(IV) reactions. This paper documents the viability of the selenium to aluminium selenide electrochemical reduction in glassy selenium, which is seldom observed with crystalline trigonal selenium. This paper challenges the naive assumption that aluminium batteries using sulfur and selenium cathodes would operate in the same way. While both are chalcogens, the bonding topologies of elemental selenium and sulfur are quite different in their most stable forms (trigonal Se chains vs. 8-membered S rings) and this leads to differences in their electrochemical performances.
Jan 14, 2024
Recently a collaborative work with Oi-Man Leung at the Unversity of Southampton was published in Advanced Energy Materials. This study represents a culmination of efforts on both the electrochemistry and applications of this new electrolyte, and also the mechanistic analyses to elucidate the molecular-scale processes within. Here, we demonstrate a huge 0.3 V improvement in the oxidative stability vs. the standard AlCl3-EMIm ionic liquid electrolyte. This increase is coupled with the inherent mechanical improvements of a polymer electrolyte, without any major sacrifice of the electrolyte conductivity. NMR spectroscopy reveals AlCl3 crosslinks between poly(ethylene oxide) (PEO) chains and some curious behvaiour of silica particles in this system…
Mar 24, 2023
Today I sucessfully defended my PhD thesis “Molecular Elucidation of Reaction Mechanisms in Aluminum and Lithium Metal Batteries by Solid-State NMR Spectroscopy and Electrochemical Methods”. My PhD journey has been a greatly enjoyable 5 years and I have far too many people to thank for getting me to this point. However, I must acknowledge my committee members, Prof. Alex Couzis, Prof. Ruth Stark, Prof. George John, Prof. Elizabeth Biddinger, and my advisor Prof. Robert Messinger for their great support today. Special thanks to Rob for all the hard work we put in together!
Feb 27, 2023
The latest work from our group “Reversible Zinc Electrodeposition at −60 °C Using a Deep Eutectic Electrolyte for Low-Temperature Zinc Metal Batteries” was published today. In this work we demonstrate an electrolyte with a deep-eutectic point to enable reversible zinc electrodeposition down to temperatures of -60 °C. We make 0.1 M Zn(TFSI)2 electrolytes in different ratios of [EMIm]TFSI with gamma-butyrolactone (GBL) which are probed electrochemically to determine their macroscopic properties, and further analysed at the molecular level via NMR spectroscopy and molecular dynamics (MD) simulations to explain the differences in performance from an atomistic approach.
Jan 25, 2023
Our new study of aluminium-organic batteries, entitled “Revealing Impacts of Electrolyte Speciation on Ionic Charge Storage in Aluminum-Quinone Batteries by NMR Spectroscopy”, is now out in the Journal of Magnetic Resonance. This is a detailed analysis of the ionic charge storage mechanisms in aluminium-quinone batteries where we begin by detailing the speciation of three different Lewis acidic ionic liquid/ionic liquid analogue electrolytes by liquid-state NMR, we then use solid-state NMR to determine the nature of the complexed ions upon electrochemical discharge in each electrolyte. We further use DFT calculations to both determine the most favorable electroactive cation generation pathways and to link the experimentally derived NMR quadrupolar parameters to a physical basis of ion interaction with different quinone structures. Finally, we also validate our hypothesised mechanisms with targeted experiments, proving the function of various ionic species.
