Dr Jennifer Johnstone-Hack

School of Chemical, Materials and Biological Engineering

Lecturer in Sustainable Materials

Royal Academy of Engineering Research Fellow

j.johnstone-hack@sheffield.ac.uk

Sir Robert Hadfield Building

Full contact details

Dr Jennifer Johnstone-Hack
School of Chemical, Materials and Biological Engineering
Sir Robert Hadfield Building
Mappin Street
Sheffield
S1 3JD

Profile: I joined the department in 2023 as a Royal Academy of Engineering Research Fellow. I completed my PhD at University College London in 2021 working on fuel cell characterisation. After several years working on battery technologies, first through an EPSRC Doctoral Prize Fellowship studying zinc-air batteries, followed by a Project Lead role on the Faraday Institution's LiSTAR project, I joined the School of CMBE to focus on hydrogen and electrochemical device research.

My research interests surround the complex relationship between materials morphology, performance and degradation in electrochemical devices. My fellowship will use 4D imaging methods, including X-ray and neutron CT, to study morphology evolution in electrolysers and will translate the insights gained into designing new structures for various electrolyser components, including the catalyst layer and porous transport layer. I also aim to develop robust processes for imaging and analysing all types of electrochemical devices, including electrolysers, batteries and fuel cells.

Research interests

Electrochemical devices, like electrolysers and batteries, are used for converting and storing green energy. They have layered material structures, and the key reactions happen at hidden interfaces between these layers. My research uses 3D tomographic imaging methods, to 'see inside' these devices while they are operating and failing. Computed tomography, or CT, is the same process used in a hospital CT-scan, e.g. if you'd broken a bone.

We aim to use the knowledge gained by looking at failure as it’s occurring, to design new, optimised materials structures. These new structures would enable devices with longer lifetimes and higher performance.

Key research interests:

4D imaging methods, including X-ray and neutron CT, in both the research laboratory and at national facilities.
Study of failure mechanisms in electrochemical devices, in particular electrolysers and fuel cells.
Understanding how materials morphology influences device performance and failure.
Proposing and designing new porous media architectures for improved performance and/or durability properties.

Publications

Journal articles

Hack J, Ziesche RF, Fransson M, Suter T, Helfen L, Couture C, Kardjilov N, Tengattini A, Shearing P & Brett D (2024) Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs. Journal of Physics: Energy, 6(2), 025021-025021.
Zucconi A, Hack J, Suter TAM, Braglia M, Shearing PR, Brett DJL & Rettie AJE (2023) In Situ X-ray imaging of HT-PEMFC hot-pressing using contrast enhancement. Journal of Power Sources, 584, 233574-233574.
Hack J, Liu Y, Neville T, He H, He G, Shearing PR & Brett D (2022) Characterisation of Anode Morphology Evolution in Zinc-Air Batteries. ECS Meeting Abstracts, MA2022-01(1), 19-19.
Chen J, Bailey JJ, Britnell L, Perez-Page M, Sahoo M, Zhang Z, Strudwick A, Hack J, Guo Z, Ji Z , Martin P et al (2022) The performance and durability of high-temperature proton exchange membrane fuel cells enhanced by single-layer graphene. Nano Energy, 93, 106829-106829.
Hack J, Patel D, Bailey JJ, Iacoviello F, Shearing PR & Brett DJL (2022) In situ x-ray computed tomography of zinc–air primary cells during discharge: correlating discharge rate to anode morphology. Journal of Physics: Materials, 5(1), 014001-014001.
Bethapudi VS, Hack J, Hinds G, Shearing PR, Brett DJL & Coppens M-O (2021) Electro-thermal mapping of polymer electrolyte membrane fuel cells with a fractal flow-field. Energy Conversion and Management, 250, 114924-114924.
Bailey JJ, Chen J, Hack J, Perez-Page M, Holmes SM, Brett DJL & Shearing PR (2021) Lab-based X-ray micro-computed tomography coupled with machine-learning segmentation to investigate phosphoric acid leaching in high-temperature polymer electrolyte fuel cells. Journal of Power Sources, 509, 230347-230347.
Shah AR, Shutt RRC, Smith K, Hack J, Neville TP, Headen TF, Brett DJL, Howard CA, Miller TS & Cullen PL (2021) Neutron studies of Na-ion battery materials. Journal of Physics: Materials, 4(4), 042008-042008.
Suter TAM, Smith K, Hack J, Rasha L, Rana Z, Angel GMA, Shearing PR, Miller TS & Brett DJL (2021) Engineering Catalyst Layers for Next‐Generation Polymer Electrolyte Fuel Cells: A Review of Design, Materials, and Methods. Advanced Energy Materials, 11(37).
Leach AS, Hack J, Amboage M, Diaz-Moreno S, Huang H, Cullen PL, Wilding M, Magliocca E, Miller TS, Howard CA , Brett DJL et al (2021) A novel fuel cell design for operando energy-dispersive x-ray absorption measurements. Journal of Physics: Condensed Matter, 33(31), 314002-314002.
Hack J, Liu Y, He G, Shearing PR & Brett D (2021) O perando lab-Based X-Ray Computed Tomography of Zn-Air Batteries. ECS Meeting Abstracts, MA2021-01(1), 42-42.
Bethapudi VS, Hack J, Trogadas P, Hinds G, Shearing PR, Brett DJL & Coppens M-O (2020) Hydration state diagnosis in fractal flow-field based polymer electrolyte membrane fuel cells using acoustic emission analysis. Energy Conversion and Management, 220, 113083-113083.
Hack J, Rasha L, Cullen PL, Bailey JJ, Neville TP, Shearing PR, Brandon NP & Brett DJL (2020) Use of X-ray computed tomography for understanding localised, along-the-channel degradation of polymer electrolyte fuel cells. Electrochimica Acta, 352, 136464-136464.
Hack J, García-Salaberri PA, Kok MDR, Jervis R, Shearing PR, Brandon N & Brett DJL (2020) X-ray Micro-Computed Tomography of Polymer Electrolyte Fuel Cells: What is the Representative Elementary Area?. Journal of The Electrochemical Society, 167(1), 013545-013545.
Wu Y, Cho JIS, Whiteley M, Rasha L, Neville TP, Ziesche R, Xu R, Owen R, Kulkarni N, Hack J , Maier M et al (2020) Characterization of water management in metal foam flow-field based polymer electrolyte fuel cells using in-operando neutron radiography. International Journal of Hydrogen Energy, 45(3), 2195-2205.
Bethapudi VS, Hack J, Trogadas P, Cho JIS, Rasha L, Hinds G, Shearing PR, Brett DJL & Coppens M-O (2019) A lung-inspired printed circuit board polymer electrolyte fuel cell. Energy Conversion and Management, 202, 112198-112198.
Heenan TMM, Tan C, Hack J, Brett DJL & Shearing PR (2019) Developments in X-ray tomography characterization for electrochemical devices. Materials Today, 31, 69-85.
Kulkarni N, Cho JIS, Rasha L, Owen RE, Wu Y, Ziesche R, Hack J, Neville T, Whiteley M, Kardjilov N , Markötter H et al (2019) Effect of cell compression on the water dynamics of a polymer electrolyte fuel cell using in-plane and through-plane in-operando neutron radiography. Journal of Power Sources, 439, 227074-227074.
Finegan DP, Darst J, Walker W, Li Q, Yang C, Jervis R, Heenan TMM, Hack J, Thomas JC, Rack A , Brett DJL et al (2019) Modelling and experiments to identify high-risk failure scenarios for testing the safety of lithium-ion cells. Journal of Power Sources, 417, 29-41.
Meyer Q, Hack J, Mansor N, Iacoviello F, Bailey JJ, Shearing PR & Brett DJL (2019) Multi‐Scale Imaging of Polymer Electrolyte Fuel Cells using X‐ray Micro‐ and Nano‐Computed Tomography, Transmission Electron Microscopy and Helium‐Ion Microscopy. Fuel Cells, 19(1), 35-42.
Kulkarni N, Meyer Q, Hack J, Jervis R, Iacoviello F, Ronaszegi K, Adcock P, Shearing PR & Brett DJL (2019) Examining the effect of the secondary flow-field on polymer electrolyte fuel cells using X-ray computed radiography and computational modelling. International Journal of Hydrogen Energy, 44(2), 1139-1150.
Tan C, Heenan TMM, Ziesche RF, Daemi SR, Hack J, Maier M, Marathe S, Rau C, Brett DJL & Shearing PR (2018) Four-Dimensional Studies of Morphology Evolution in Lithium–Sulfur Batteries. ACS Applied Energy Materials, 1(9), 5090-5100.
Hack J, Heenan TMM, Iacoviello F, Mansor N, Meyer Q, Shearing P, Brandon N & Brett DJL (2018) A Structure and Durability Comparison of Membrane Electrode Assembly Fabrication Methods: Self-Assembled Versus Hot-Pressed. Journal of The Electrochemical Society, 165(6), F3045-F3052.
Tate ML, Hack J, Kuang X, McIntyre GJ, Withers RL, Johnson MR & Radosavljevic Evans I (2015) Bi1−Nb O1.5+ (x=0.0625, 0.12) fast ion conductors: Structures, stability and oxide ion migration pathways. Journal of Solid State Chemistry, 225, 383-390.
Zucconi A, Hack J, Stocker R, Suter TAM, Rettie AJE & Brett DJL () Challenges and opportunities for characterisation of high-temperature polymer electrolyte membrane fuel cells: a review. Journal of Materials Chemistry A.
Altus SJ, Inkson BJ & Hack J () Complementary X-ray and neutron imaging of water electrolysers for green hydrogen production. Journal of Materials Chemistry A.
Ziesche RF, Hack J, Rasha L, Maier M, Tan C, Heenan TMM, Markötter H, Kardjilov N, Manke I, Kockelmann W , Brett DJL et al () High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells. Nature Communications, 13(1).

Chapters

Giri G, Brett D, Shearing P & Hack J (2025) Zinc-air batteries, Electrochemical Energy Storage Technologies Beyond LI-ION Batteries (pp. 369-403). Elsevier

Conference proceedings papers

Hack J, Meyer Q, Iacoviello F, Cullen P, Mansor N, Shearing P, Brandon N & Brett D (2017) A MULTI-SCALE APPROACH TO POLYMER ELECTROLYTE FUEL CELL CHARACTERISATION. EFC 2017 - Proceedings of the 7th European Fuel Cell Piero Lunghi Conference (pp 235-236)

Teaching activities: MAT61021: Energy Generation and Storage