2-D materials as the next generation membranes in hydrogen generation and low temperature fuel cells.

Fuel cells have been promoted as a pollution free alternative for energy generation when converting hydrogen into electricity. There are several constraints which have limited the implementation of this technology and this proposal addresses all of the major problems.

To make hydrogen requires energy and using conventional methods requires electricity to electrolyse water, if the electricity comes from fossil fuels then the problem is simply moved rather than solved. To use renewable energy requires electrolysers where the energy intermittently generated by the source (wind, solar, tidal etc) is converted into hydrogen at source by an on-site Polymer Electrolyte Membrane (PEM) Electrolyser. The problem with PEM electrolysers is that the membrane used needs to be thick to prevent hydrogen mixing with oxygen to form an explosive mixture but the thickness of the membrane reduces efficiency.

Similar problems manifest themselves in fuel cells, the conversion of hydrogen back into electricity requires a PEM fuel cell, the membrane is the same as in the electrolyser and again needs to be thick to prevent fuel crossover but this again reduces efficiency. A third technology, the Direct Methanol Fuel Cell (DMFC) was developed to address the problems around hydrogen storage but again the membrane is the same and again thickness and fuel crossover constrain the efficacy of the membrane.

In this work we intend to take the properties of the graphene and hexagonal boron nitride (hBN) which have been proven to allow protons to pass but prevent all other transport of materials and apply them to the three technologies discussed. The materials challenges around the manufacture of a defect free barrier membrane will be tackled with the added benefit of utilising the expensive platinum catalyst more efficiently.

The potential benefit of this work is that hydrogen production will become more efficient and the cost of converting the fuel into electricity in a fuel cell will decrease as the overall cost of the fuel cell is reduced. This will make viable the use of 'green hydrogen' as an energy storage medium and enable the route to market for PEM fuel cells which are necessary to convert the hydrogen (and other fuels such as methanol) into electrical energy. Another potential benefit of this study is the complete replacement of the membrane material by a supported graphene or hBN. This will facilitate the reduction in volume of a fuel cell, as the fuel will no longer need to be humidified so there will be fewer components, which is important for mobile/portable applications.

The environmental and societal impacts of energy generation using sustainable sources cannot be overstated and has received national and global exposure. Fuel cells and the hydrogen economy along with renewable resources comprise a significant component in most strategies to combat climate change.

The problems around renewable resources focus on the intermittent nature of the generation and hence storage of the power is essential. A simple and effective way of storing the power is as hydrogen which can then be converted into electricity and water by fuel cell technology. The majority of the limitations around hydrogen generation and the operation of fuel cells relate to the cost and efficiency of the technology which is based around the membrane used in electrolysers and fuel cells and the expense of the platinum catalyst which is required for the processes.

In this work we will produce a significant increase in the barrier properties of the membrane which will in turn allow thinner membranes to be used increasing efficiency and reducing the unit cost of the equipment. The additional benefit of the enhanced utilisation of the expensive catalyst will also reduce capital cost.

These impacts will be felt ultimately by society due to the greater uptake of the 'green hydrogen' economy and hence benefit to the environment and quality of life. In addition, companies who manufacture the technology (eg ITM Power) and components for the membranes (eg 2D Tech) will have greater marketability for their products. End users of electrolysers and fuel cells such as renewable energy generation companies and automobile manufacturers will have a more efficient and cost effective product to incorporate into their systems.