Calcium-sulphur (Ca-S) batteries hold the promise of high energy density batteries, consisting of low-cost, abundant, non-toxic materials, calcium anode and sulphur cathode. The proposed project aims at developing a room-temperature Ca-S battery reaching an energy density of 400 Wh/kg of cell, and very good cyclability and lifetime. Such batteries would be very popular for long driving range EVs, other transport means such as electric and hybrid aircraft, and stationary storage linked to renewables on the grid or microgrids. Ca-S batteries are a pioneering solution to accelerate the net-zero transition, while calcium and sulphur will reduce society dependencies on lithium and other rare critical raw materials, such as cobalt, nickel and magnesium, associated with current Li-ion batteries.

CL’s group have already developed high performance sulphur cathodes, which were tested successfully for lithium-sulphur (Li-S) and sodium-sulphur (Na-S) batteries. The benefit of our novel cathodes lies in limiting the shuttling of polysulphides, which means that our cathodes raise the specific capacity and cyclability of sulphur batteries. The proposed PhD is based mainly on experimental work, employing and refining our novel cathodes, taking into account that the Ca-S battery volumetric expansion is expected to be very similar to that observed in Li-S batteries (half of that in Na-S batteries). Novel developments proposed for this PhD include optimising the cathode host structure, investigations of different liquid electrolytes and additives, as well as anode protection. Our group offers additional infrastructure in terms of in operando UV-vis spectroscopy using the portable UV-vis system in CL’s lab and a unique XPS instrument for composition analysis in depth below the specimen surface providing a composition profile through depth. CL’s group is also providing algorithms for the simulation of charge-discharge of a Ca-S cell, based on a physicochemical model taking into account the pore size distribution of each cell component.

In REF-2021, 43% of the research in engineering at University of Surrey (UniS) was rated world-leading, and 92% of the research in engineering at UniS was rated world-leading and internationally excellent. UniS was ranked 15th for research power in engineering.

Supervisors: Professor Constantina Lekakou , Dr Daniel Commandeur and Professor Mark Baker

Funding

This is an EPSRC Doctoral Landscape Award, covering UKRI standard stipend (£20,780 for 2025/26 academic year) and fees at home-fees rate.

Open to any UK or international candidates. Up to 30% of our UKRI funded studentships can be awarded to candidates paying international rate fees. Find out more about eligibility .

Start Date

October 2025

Entry requirements

You will need to meet the minimum entry requirements for our PhD programme .

Candidate Profile

Candidates with a BEng or BSc or Master degree in any engineering discipline, physics, chemistry or materials, at a minimum grade as follows: first or upper second-class (2:1) UK degree or equivalent non-UK degree, or a lower-second (2:2) UK degree plus a good UK masters degree - distinction normally required (or equivalent overseas qualification). Also if non-UK, English Language requirements as in Engineering Materials PhD Programme webpage.

How to Apply

Applications should be submitted online via the Engineering Materials PhD programme page. Please choose entry October 2025, Full-time, PhD Programme: Engineering Materials.

In place of a research proposal you should upload a document stating the title of the project that you wish to apply for: “Calcium-Sulphur Batteries”, Advert Reference, and the name of the supervisor: Constantina Lekakou. Please email: [email protected] that you have applied and the applicant number that you have received in your application receipt.