Johanna Rosén and PhD student Andrejs Petruhins discuss a problem with the coating system Hydra, designed by Johanna Rosén herself. Photo credit: Anna Nilsen
The Swedish Foundation for Strategic Research has awarded nearly SEK 300 million to nine research projects to investigate and develop materials for energy systems. The research will take place in close collaboration with industry, with the goal of developing new materials for more efficient and more sustainable energy systems.
Vanya Darakchieva, senior lecturer in the Department of Physics, Chemistry and Biology has been awarded a five-year grant of SEK 35 million for research into group-III nitride technology, which has potential applications in energy-efficient high-power electronic devices.
One effective way to save energy is to reduce energy losses in electrical systems. Most of the electrical energy that is produced will pass through at least one conversion, in components known as AC/DC and DC/DC converters. The efficiency of the today's converters is so low that up to 65% of the energy can be lost. This is where group-III nitrides come into the picture, since they can be used to form effective, high-power electronic devices that have high energy efficiency. The technology uses such materials as gallium nitride (GaN) and aluminium gallium nitride (AlGaN), but is currently too expensive for large-scale use.
One of the challenges is to produce extremely pure layers that can cope with high voltages, over 1 kV. In addition, bulk substrates made from the same material as the rest of the components are required, and AlGaN substrates are not currently available. Thus, the research is aimed at using innovative technology based on nanowires to develop AlGaN and GaN substrates free of defects. Layers of the same material are deposited onto these substrate layers to create device structures for next-generation junction diodes and switches.
"We plan to develop a cost-effective process for high-power components of group-III nitrides in the project. These will make possible a rapid transition to efficient conversion, transport and use of electricity," says Vanya Darakchieva.
Supercapacitors of the future?
The other five-year project has been awarded SEK 33.7 million and is led by Johanna Rosén, professor in the Department of Physics, Chemistry and Biology. It is focused on research to develop new materials that can be used to preserve and use energy from renewable sources. One such technical solution is electrochemical energy storage, which includes storage in batteries and supercapacitors. One distant goal is to combine in a single component the ability of a battery to store large amounts of energy with the ability of a supercapacitor for rapid charging and discharging.
The researchers plan to design and develop new two-dimensional materials for electrochemical storage. They are particularly interested in substances known as "MXenes", which are similar to graphene, which is another, well-known, two-dimensional carbon material. In contrast to graphene, the MXenes constitute a family of materials, which opens the possibility for the researchers to modify the composition of the material and tailor its properties to improve its ability to store energy. The researchers are using supercomputer simulations in an attempt to predict the types of atom that are best suited, and in this way guide the experiments carried out in the laboratory.
"I hope that the project will lead to excellent components for energy storage. Supercapacitors are currently being used, for example, in trains in Japan, where the capacitors can rapidly capture the energy generated when the train brakes, such that it can then be immediately used when the train accelerates. Saving energy in similar ways is possible in many different areas in our society, and it is here that I hope that our material can be useful," says Johanna Rosén.