Probing Buried Interfaces in Solid-State Batteries Using Photoelectron Spectroscopy

Improvements in the performance and cost of rechargeable batteries are vital to encouraging wider adoption of electric vehicles. The electrode-electrolyte interfaces in Lithium-ion batteries are critical to achieving long battery lifetimes, and fast-charging rates. Over many charge-discharge cycles or when operated under conditions of stress (e.g. voltage, temperature, rate), undesirable side reactions occur at these interfaces such as surface phase-transformations, electrolyte decomposition, and gas evolution.  Most techniques to look at these electrode-electrolyte interfaces require disassembly of the battery, due to the major challenge of accessing such buried interfaces.  However, these approaches are unreliable as battery interfaces are usually highly reactive and liable to change during disassembly and transfer to the measurement system.

This DPhil (PhD) project aims to investigate the reactions occurring at the interfaces between electrodes and solid-electrolytes as they happen.  This will use capabilities recently developed in the group to deposit model thin film electrodes, which are thin enough to remain transparent to photoelectrons. The interfaces formed with solid-electrolyte materials can then be probed using techniques such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) whilst the battery is being charged/discharged. The aim is to understand the stability of these interfaces under various cycling conditions, and mechanisms by which they degrade. This understanding will then be used to identify material combinations or treatments that reduce interfacial resistance and increase battery lifetime.

Any questions concerning the project can be addressed to Dr Robert Weatherup (robert.weatherup@materials.ox.ac.uk).

General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk.  You must complete the standard Oxford University Application for Graduate Studies.  Further information and an electronic copy of the application form can be found at https://www.ox.ac.uk/admissions/graduate/applying-to-oxford.