Ben Jagger

I am a Postdoctoral Research Associate in Solid-State Batteries in the Department of Materials, working with Prof. Mauro Pasta. For my undergraduate degree I read Materials Science in Oxford (2017–2021, St. Anne’s College) and I was then awarded a Clarendon Scholarship to remain in the department and complete my DPhil in the Pasta Group (2021–2025, St. Edmund Hall). Alongside my DPhil I was an undergraduate tutor at St. Edmund Hall, holding a College Lectureship in Materials Science from 2023 to 2025.

I am interested in understanding the processes that limit rate performance and long-term stability in battery systems. My focus is on lithium metal and potassium-ion batteries, which require insights that can be translated into rational design principles that overcome these limitations.

I provide small-group teaching to 1st and 2nd year undergraduate students, as well as revision sessions for 3rd years preparing for their Finals Examinations. I cover a range of topics including electrochemistry, thermodynamics, phase transformations, and electronic structure of materials. Outside of Trinity College I have supervised several summer interns through the Faraday Undergraduate Summer Experience (FUSE) scheme, and I support Part II students as they complete their 4th year research projects.

My research focusses on understanding the processes limiting battery performance, including electrolyte transport, electrode kinetics, and the solid electrolyte interphase (SEI). To do this I use a range of materials and electrochemical characterisation techniques, particularly X-ray photoelectron spectroscopy (XPS) which is a surface-sensitive technique that provides information about the elements present in a material and their chemical state.

High-energy negative electrode materials are highly reactive and decompose the electrolyte, leading to the deposition of a thin layer of decomposition products that ideally protects the electrode from further reaction, known as the SEI. My current work explores the differences in the SEI between lithium- and potassium-based battery systems and aims to establish links between the electrolyte chemistry and the properties of the SEI. My goal is to use this understanding to design better electrolytes that result in superior battery stability.

Cattermull, J., Jagger, B., Cassidy, S. J., Dhir, S., Allan, P. K., Pasta, M. & Goodwin, A. L. ‘Nonequilibrium ion transport in a hybrid battery material.’ Sci. Adv. 12, eaed1629 (2026).

Jagger, B., Xu, Y., Allen, C. S. & Pasta, M. ‘Chemical vs. electrochemical solid electrolyte interphase formation in potassium-ion batteries.’ Faraday Discuss. (2026)

Olbrich, L. F., Pianta, N., Jagger, B., Xu. Y., Kakkanat, M., Scarpioni, F., Allen, C., La Mantia, F., Ruffo, R. & Pasta, M. ‘Electrochemical impedance spectroscopy investigation of the SEI formed on lithium metal anodes.’ ACS Electrochem. 2, 166–174 (2026).

Burton, M., Jagger, B., Liang, Y., Gibson, J. S., Aspinall, J., Swallow, J. E. N., Weatherup, R. S., & Pasta, M. ‘The role of phosphorous in the solid electrolyte interphase of argyrodite solid electrolytes.’ Nat. Commun. 16, 9304 (2025). 

Burton, M., Narayanan, S., Jagger, B., Olbrich, L. F., Dhir, S., Shibata, M., Lain, M. J., Astbury, R., Butcher, N., Copley, M., Kotaka, T., Aihara, Y., & Pasta, M. ‘Techno-economic assessment of thin lithium metal anodes for solid-state batteries.’ Nat. Energy 10, 135–147 (2025). 

Jagger, B., Aspinall, J., Kotakadi, S., Cattermull, J., Dhir, S., & Pasta, M. ‘Potassium alloy reference electrodes for potassium-ion batteries: The K-In and K-Bi systems.’ ACS Mater. Lett. 6, 4498–4506 (2024). 

Jagger, B. & Pasta, M. ‘Solid electrolyte interphases in lithium metal batteries.’ Joule 7, 2228–2244 (2023). 

Dhir, S.*, Jagger, B.*, Maguire, A. & Pasta, M. ‘Fundamental investigations on the ionic transport and thermodynamic properties of non-aqueous potassium-ion electrolytes.’ Nat. Commun. 14, 3833 (2023).