About the project

What is the purpose of the project?

The project aims to develop and manufacture a new solid oxide fuel cell stack type. Fuel cells are devices that directly convert a fuel’s chemical energy into electricity. Direct conversion means that a fuel cell is very efficient. High energy-conversion efficiency means lower fuel consumption, less material consumption, and less pollution emitted into the environment. The supreme achievement of fuel cell technology for stationary applications is a solid oxide fuel cell.

Due to the high operating temperature and the oxygen-conducting electrolyte, this fuel cell type can oxidize the hydrogen and carbon monoxide mixture from the gas reforming process. A typical solid oxide fuel cell consists of two electrodes, anodes, and cathodes, separated by a solid oxide electrolyte. In the production of such cells, the sintering of large-area electrodes is the most significant problem.

Solid oxide fuel cells currently used in pilot plants often have an active surface area exceeding 50 cm2. The sintering of thin metal-ceramic composites with such a surface is challenging. Customized furnaces with a uniform temperature distribution, gas circulation, and an appropriate sintering setting are required, usually the manufacturer’s intellectual property.

Also, a fuel cell with a large surface area is exposed to large temperature gradients during operation, which may damage the cell due to thermal stresses. Single cells provide a very low voltage of 1 V. Therefore, and the cells are stacked. In the fuel cells stack between each cell, oxidant (most often air) and fuel (hydrogen or natural gas) is passed alternately. This causes great difficulties in sealing such an arrangement of the cells. The proposed cell stack design solves all of the problems mentioned above.

What constitutes innovation?

It is the first of its kind in the world. The stack is designed in such a way to be easy to manufacture and easy to seal. The shortcomings of the construction simplicity are compensated for by the microstructure-oriented design. In the proposed device, the microstructure is tailored to suit the specific requirements of a cell, depending on the location in the stack and the location of a single cell.

The microstructure-oriented design has been made possible by developing measurement techniques such as FIB-SEM electron tomography coupled with a 3D reconstruction technique. In these tests, the scanning ion microscope (the so-called FIB) cuts the sample into 200-300 slices sequentially scanned with a scanning microscope (SEM). The collected SEM images are then used to develop a full three-dimensional reconstruction of the microstructure. The technology used for SOFC research for the first time in 2006 brought previously unknown cognitive possibilities in the electrode material.

To date, only a few research centers in the world can adequately carry out quantitative analyses of the porous material’s microstructure. The proposed multi-scale numerical calculations, taking into account micro and macro phenomena, mutual interactions, and indirect reforming, are also innovative. The simulation has a significant cognitive value in unveiling fundamental phenomena occurring in a fuel cell’s stack in addition to design values.

What applications might the project results have?

Cheap and easy-to-manufacture SOFC fuel cells may bring a change in how Polish households are powered. It is clean energy – the only exhaust gases in fueling the cell with natural gas are carbon dioxide and water vapor. The cell also performs heating functions. An installation with a power of 1 kW of electricity produces 700 W of thermal energy in parallel, which can be used to heat water and the home.

Unlike a classic power plant, a solid oxide fuel cell can respond dynamically to energy demand. This means that the cell can generate electricity exactly in time and in the amount that is needed. It can be part of a system with solar panels or a ground heat exchanger. Such a dynamic response of the system is also studied in the project. 

The introduction to the market of fuel cells generating electricity using natural gas will increase competition between energy and gas companies. Oxide fuel cells can be combined with coal gasification, allowing for extremely effective fossil fuel use. In this concept, known as IGFC (Integrated Gasification Fuel Cell cycle), the synthesis gas from coal gasification is oxidized in fuel cells, then the gas residues are directed to the gas turbine. The exhaust gases’ temperature is so high that they are used to produce steam that feeds the steam turbine. Such a triple cycle can achieve an efficiency of 60% (coal gasification) or 70% (natural gas).