Scientists at Tomsk Polytechnic University are developing solid oxide fuel cells. A fuel cell made of several of these elements is the “heart” of power plants that generate electricity from hydrocarbon fuels or hydrogen.
To create one of the key elements of a fuel cell – an electrolyte – scientists at TPU and the Institute of High Current Electronics of the SB RAS for the first time in Russia proposed using the magnetron sputtering method. Thanks to this method, they managed to obtain a very thin electrolyte layer – no more than 5 microns. This made it possible to reduce the temperature at which power generation occurs by 100 ° C. This directly affects the service life of fuel cells: the lower the temperature, the longer the service life of the cells.
Solid oxide fuel cells are devices for converting fuel energy into electrical energy and partly into thermal energy without burning it. They can handle hydrocarbon fuels such as methane and butane, as well as hydrogen. The fuel cell is a plate of three layers: cathode, anode and electrolyte between them. In the power plant, hydrogen and air are supplied to them from different sides. Oxygen ions and hydrogen molecules meet, and a chemical reaction occurs between them, as a result of which heat and electricity are generated. A by-product of the reactions is pure water.
“Solid oxide fuel cells have two major advantages. First, their electrical efficiency reaches 60%, while thermal, gas turbine or nuclear power plants have an efficiency of 40%. The difference is significant. Secondly, they are environmentally friendly.”
That is why today they pay attention to them all over the world. However, until now, such elements are not widespread. Scientists all over the world are looking for ways to get even more efficient, reliable and cheap fuel cells to speed up their adoption. In Tomsk, the direction of applying thin-film coatings by the method of magnetron sputtering has been developing for a long time, so we decided to try to apply the electrolyte by this method. And we got a good result: 5 microns is one of the best results today among other methods of applying electrolytes, ”says Associate Professor of the Scientific and Educational Center B.P. Weinberg TPU Andrey Soloviev .
The electrolyte in a fuel cell acts as a barrier between hydrogen and oxygen molecules. If you mix them directly, an explosion can occur. The electrolyte layer allows only oxygen ions needed for a safe reaction to pass through. It is a thin film of yttrium-stabilized zirconia and gadolinium-doped cerium oxide. Electrolyte is applied to the ceramic anode.
“The essence of the magnetron sputtering method is knocking out (sputtering) atoms of a substance from the surface layers of the target with ions of the working gas, usually argon, and their subsequent deposition on the substrate,” says Yegor Smolyansky, engineer of the TPU Research School of Physics of High-Energy Processes .
Tomsk Polytechnic Institute has created its own vacuum magnetron sputtering unit for the application of such coatings.
“Typically, solid oxide fuel cells operate at an average temperature of 850 ° C. Ours – at 750 ° C. This is due to the fine electrolyte. Reducing the operating temperature affects the life of the fuel cell stack as lower temperatures reduce the rate of degradation of materials. The thin electrolyte also allows for higher power density. This means that with the same size of the fuel cell, more energy can be produced. To find out how much the service life of the elements can be increased, it is necessary to carry out long-term life tests, ”notes Yegor Smolyansky.
Tomsk Polytechnic University initiated the creation of the Technological Hydrogen Valley consortium. Its participants will conduct joint research and develop technologies for hydrogen production, transportation, safe storage and use in energy.
The consortium includes the Institute of Catalysis of the SB RAS, the Institute of Problems of Chemical Physics of the RAS, the Institute of Petrochemical Synthesis of the RAS, the Samara State Technical University and the Sakhalin State University.