While the first fuel cell-propelled cars are expected on UK roads in 2015, their success depends to a very large extent on the widespread availability of pure hydrogen fuel and a fuelling infrastructure. The UK government recently announced the provision of £11M for the roll-out of a hydrogen fuelling infrastructure, but hydrogen is currently generated industrially by steam reforming natural gas, an unsustainable process that co-generates carbon dioxide and contributes to global warming. Electrolysis of water is by far the most sustainable method for generating pure hydrogen and the major technologies under development are (i) alkaline electrolysis, (ii) high temperature solid oxide electrolysis, and (iii) proton exchange membrane (PEM) electrolysis. However, each of these technologies suffers from serious economic, technological, and/or safety limitations. Intermediate-temperature PEM electrolysers operate in the temperature range 150-300 celsius and offer significant advantages over other electrolysers, including potentially lower running costs, the ability to deliver compressed hydrogen, and high thermodynamic efficiencies. However, to capitalise on these advantages, a number of issues must still be addressed; in particular, the performance and stabilities of PEMs in the intermediate-temperature range must be improved and the reliance of these devices on noble-metal catalysts must be mitigated. In this project, we aim to solve both of these problems by developing a new generation of PEM electrolysers that contain proton-conducting ionic liquids as the electrolyte. The use of these materials as proton conductors within PEMs will allow us to use non-precious, Earth-abundant electrocatalysts to effect hydrogen and oxygen evolution, and to solve the stability issues hampering state-of-the-art PEM electrolysers, advances that will lead to a step-change in PEM electrolyser technology.