Hydrogen Electrolysis
Researchers: Professor Andy Woods, James Morris, Haihan Li, Professor Stuart Clarke
The Problem
Current hydrogen electrolysers operate at only 40-60% efficiency, creating significant energy waste and limiting their effectiveness for renewable hydrogen production.
Work Needed
Improving electrolyser efficiency is vital for the energy transition and this requires new designs for electrodes and electrolytes, better control of hydrogen bubble formation, and innovative ways to capture waste heat energy.
Our Work
We are exploring ways to make hydrogen production more efficient by investigating how bubbles form and move on electrodes, using advanced imaging and modelling techniques to optimise the process.
Background
The energy efficiency of hydrogen electrolysers is presently in the range of order 40-60% for commercial electrolysers and if we are planning to generate hydrogen through renewable electricity there is a strong incentive to improve this efficiency to orders of 80-90%. This requires development of a series of new approaches to the design of electrodes, the electrolyte, and the overall operation of the electrolyser. There is also opportunity to capture some of the thermal energy produced as waste heat which is the manifestation of some of this inefficiency in Hydrogen production.
Our Work
Research in the institute is exploring the potential for new materials and new structures by which the electrolytes can be more efficient (Dr Rafia Nimal). There is also significant research on alkaline electrolysers, focusing on a fluid electrolyte where controlling the formation of hydrogen bubbles on the electrode can yield substantial benefits by improving the utilisation of the electrode in hydrogen generation. The experiments involve advanced visualisation techniques and image processing and are coupled with models of the associated two phase convective flows. This research is ongoing, modelling the nucleation and growth of bubbles on electrodes and exploring different electrode designs with the purpose of improving the control, and hence utilisation efficiency, of the electrode in generating gas.
Initial results have identified a series of approaches to improve the efficiency of the gas production through control of bubble size distribution produced on the electrode. One important element arising from this concerns the convective circulation of the electrolyte caused by the generation and migration of bubbles through the electrolysis cell which in turn has an important rate-limiting factor on supply of ions to the electrode.
Photos of electrolysis experiments
Future Directions
New experiments are being carried out explore these convective flows with a view to further improving the efficiency of gas production.