PhD Studentship: Nanoscale Diamond Quantum Sensors for In-Situ Detection of Reactive Radicals in Fuel Cell Membranes

Supervision:

Dr Helena Knowles (Cavendish Laboratory) in collaboration with industry partner Johnson Matthey (JM).

A fully funded PhD under the EPSRC CASE conversion studentship is available at home student fee rates in the Department of Physics, Cavendish Laboratory, with a starting date of 5 January or 17 April 2025.

Hydrogen fuel cells, based on proton exchange membranes (PEM), are being developed and commercialized for heavy duty transportation applications. This technology enables fully electric, carbon free, transportation with long range and rapid refueling.  Key to the success of fuel cells in this market is extended durability over 30,000 hours, the equivalent of one million miles of operation. 

The current state of the art membranes are made from perfluorosulfonic acid (PFSA) ion conducting polymers (ionomers).  These materials have exceptional proton conductivity, mechanical strength, and chemical stability.  Despite the fully fluorinated nature of these membranes, they are subject to chemical degradation over extended time. Under some operating conditions, low levels of side products such as hydrogen peroxide, hydroxyl radicals (HO·), or hydrogen atoms (H·) can be formed.  These reactive species are known to degrade the membrane resulting in premature failure. 

Understanding the nature and location of these radicals is needed to advance the development of new membrane materials. Advances in both membrane materials and radical scavenging additives are needed to meet the aggressive lifetime targets for fuel cell applications.  A necessary step in this process is a non-invasive means of detecting and quantifying the reactive species in an operating cell in a way that enables probing the type, concentration, and location of these radicals.

The nanodiamond quantum probe developed at the University of Cambridge has the potential to provide high spatial resolution and high sensitivity radical detection in operating fuel cells.  This technique involves probing atomic defects hosted in the diamond crystal through combined microwave and optical excitation. The defects respond selectively to changes in their environment, such as temperature, pH or concentration of different radical species, and allow us to probe these parameters independently at the nanometre scale and in a time-resolved fashion.

The main aims of the project are:

1) Validating the quantum sensing method on membranes with simple out-of-cell experiments
2) Designing a specialized fuel cell fixture with a nanodiamond probe capable of measuring radicals during operation

3) Probing effects of different membrane materials and additives at the nanoscale to inform the design of next generation fuel cells

This project will be collaboration between the University of Cambridge and Johnson Matthey (JM), a global leader in sustainable technologies, and a market leader in performance components for fuel cells and electrolysers. This project offers an exciting opportunity to develop the quantum sensing characterisation tools which will contribute to the development of next-generation fuel cells needed as the world transitions to a net-zero economy.

You should have a First Class (or high Upper Second Class) mark in all previous degrees in a relevant discipline such as physics, chemistry, electrical engineering, chemical engineering or a related subject.

Fixed-term: The funds for this post are available for 3.5 years in the first instance.

The deadline for applications is 8 September, with interviews to be conducted the following week.

When applying, please ensure you upload 2 academic references , transcript, CV and evidence of competence in English language if required.

The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.

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