Water dissociation interfaces for high current density bipolar membrane electrolysers

Lead Research Organisation: University of Liverpool
Department Name: Chemistry

Abstract

Hydrogen gas is predicted to become an important fuel for industry, energy storage medium and an alternative heating fuel. Therefore an urgent need exists to develop ways to generate hydrogen from non-fossil resources, avoiding the generation of carbon dioxide as a by-product. Zero carbon hydrogen can be generated by the electrolysis of water using renewable power with oxygen being the only other product. This is a promising approach, providing a way to increase market penetration of renewable power by providing a long-term energy store which overcomes issues relating to intermittency of supply. The current leading water electrolysis technology operate in acid. Whilst the hydrogen evolution reaction is efficient in acid the oxygen evolution reaction is not. For acid electrolysis the only active catalysts for oxygen production have a very low availability and there is insufficient to meet predicted demand. An alternative is to carry out electrolysis in base, whilst a range of available oxygen evolution catalysts exist, the efficiency of the hydrogen evolution catalyst is decreased. To deliver electrolysis at a global scale alternative technologies are needed.

From an electrocatalyst perspective the ideal electrolyser would run the hydrogen evolution reaction in acid and the oxygen evolution reaction in base. This would make use of the existing, scalable electrocatalysts. Bipolar membrane electrolysers achieve this. When the bipolar membrane is reverse biased sufficiently water within it dissociates and protons are transported towards the hydrogen evolution electrode, generating an acid environment and hydroxide to the oxygen evolution site, generating a basic environment. Bipolar membrane electrolysers represent a third, but massively under-researched, way to generate zero-carbon H2 by electrolysis and importantly they can be delivered at the scale required.

But to be a viable technology large improvements in efficiency and stability of the bipolar membrane are needed. Historically issues relating to water transport across the membrane, which lead to dehydration, and also delamination have caused instabilities but recent studies have shown that these can be largely addressed by careful control of the polymer membrane thickness. What has not been solved is the large losses associated with the low efficiency of water dissociation within the bipolar membrane. Addition of catalyst layers into the bipolar membrane is a promising approach but more research is urgently needed. Here we will develop new water dissociation interfaces within the membrane structure with metal oxide catalysts that are optimised for the local pH environment to impart both high levels of activity and stability. Our proposed innovative interface design will explore how to maximise the local electric field and the catalytic enhancement of water dissociation whilst minimising resistance losses in the membrane, to deliver a step change in water dissociation activity and demonstrate the viability of zero carbon hydrogen by bipolar membrane electrolysis.

Publications

10 25 50
 
Description We have developed new capabilites for the preparation of advanced bipolar membranes for use in electrolysers and demonstrated membranes that can achieve benchmark activites for green H2 production and carbon dioxide reduction. The bipolar membrane structure overcomes many of the limitations of conventional room temperature electrolysers that rely on high levels of PGM's. This has led to high levels of interest from industry to access expertise/capabilities of the project.
Exploitation Route We have achieved a large portion of the awards outcomes (as of Feb 2024). The membranes allow for use of earth abundant catalysts in electrolysers without the need for PGM. The membranes developed are of interest to our partners (JM, INEOS) for use in electrolysers and we have also attracted interest from BP, Baker Hughes, NSG group and Cambridge display technologies who have held initial meetings on accessing the capabilities/expertise developed.
Sectors Chemicals

Energy

 
Description Contribution to policy paper from RS on green chemicals industry
Geographic Reach National 
Policy Influence Type Participation in a guidance/advisory committee
 
Description ICURE - discover
Amount £3,700 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 11/2023 
End 03/2024
 
Description Collaboration with JM on BPM in electrolyser 
Organisation Johnson Matthey
Country United Kingdom 
Sector Private 
PI Contribution The University of Liverpool team has prepared new membrane structures and tested these in electrolysers with guidance and advice from JM on the project direction.
Collaborator Contribution As an industry partner JM has been active in project meetings inputting on the choice of materials used in the membrane and also on the testing approaches used to assess the materials.
Impact not yet
Start Year 2023
 
Description Interview for naitonal newspaper (FT) 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Interview with Financial Times (UK) on green hydrogen to give perspective on the fasibility of seawater electrolysis, a process that will require the membrane tpyes studied here.

Multiple company enquiries since regarding development projects that build on this UKRI project technology. Plans in development.
Year(s) Of Engagement Activity 2022
URL https://www.ft.com/content/aeab5699-8532-47be-a395-656c01b3ca48