Increasing consumption of fossil energy sources such as oil, coal and gas has led to increasing climate challenges in the world. All countries agree that good access to cheap and clean energy is crucial for the development of a sustainable world. Clean energy is energy that is made from renewable energy sources such as solar, wind and hydropower. Renewable energy is not always available in places where the energy is needed or when you need it. It must therefore be possible to store and transport renewable energy. Hydrogen has a high energy content and can be made by using renewable energy to split water into hydrogen and oxygen gas. This process is called water electrolysis, in which electric current is applied between two electrodes in contact with water.
A challenge with renewable energy sources such as solar and wind is that the amount of energy available is variable. PEM water electrolysis is a technology that is well suited for converting variable renewable energy into hydrogen. It consists of a solid polymer membrane coated with catalysts on both sides and sandwiched between two electrodes. The most efficient catalysts in PEM water electrolysis are based on rare and expensive elements. In fact, the annual need is already greater than the global production for one of these elements. It is therefore crucial to reduce the usage of rare elements to avoid a bottleneck against the upscaling of this green technology.
In the HOPE project, SINTEF and NTNU are collaborating to develop the next generation of PEM water electrolysers. Alternative catalysts must be developed and utilized more efficiently, the interface between the catalyst, the electrode and the membrane must be improved, and the performance and service life of PEM water electrolysers must be enhanced. The objective for HOPE is to provide us with new knowledge that enables us to utilize renewable energy more efficiently through green hydrogen production in PEM water electrolysis.
Efficient water electrolysis is a requirement for implementation of green hydrogen as a renewable energy carrier. Proton Exchange Membrane Water Electrolysers (PEMWE) is well suited to be coupled with intermittent power sources such as wind and solar, and offers many advantages compared to the traditional alkaline technology. However, for efficient oxygen evolution reaction in the acidic and oxidizing environment at the anode, scarce and expensive Ir-based catalyst is the current industry standard. Limited conductivity within the catalytic layer (CL), degradation of the catalyst and deterioration of the interfaces between the porous transport layer (PTL), CL and the membrane lead to poor electrolyser performance over time. A fairly high loading of Ir-based catalyst is therefore needed in conventional systems to obtain an appreciable lifetime. The extensive use of Ir is a contributing factor to the high capital cost of PEMWE and places a limitation for the upscaling of the total capacity of installed PEMWE. For GW water electrolysis installation there is a desire to reach Ir-loadings of 50 mgIr kW-1 or less. Improved catalyst utilization, alternative catalyst materials, optimized electrode architecture and stability of the CL interfaces, and optimized PEMWE operation that maximizes performance and durability are all key aspects to lower Ir-loading in PEMWE systems and are almost exclusively investigated separately. This project will pursue all these aspects, but most importantly, we will combine them using state-of-the-art manufacturing and synthesis procedures, electrochemical modelling and novel PEMWE operation procedures. This project will arrive at a new standard for iridium utilization in PEMWE systems.
The project will employ a PhD student at NTNU that will be trained in electrochemistry, fabrication and characterization of PEMWE electrodes and electrochemical modelling for optimizing electrode design and PEMWE operation.