Supplying hydrogen cheaply using highly efficient, long-life systems
Again, the system efficiency is plotted on the vertical axis. The service life, namely, the period until disposal of a system, is plotted on the horizontal axis. As I mentioned earlier, SOECs operate at high temperature, so they have problems in terms of durability. (If the durability is low) customers must replace systems frequently. We aim to manufacture highly durable systems while maintaining the efficiency in order to supply hydrogen at low cost to customers over the long term.Interdisciplinary development by experts in chemical reaction engineering, electrochemistry, and solid-state ionics
Next, let me explain the development of cell stacks for SOECs, which I am working on, based on examples.
A cell of an SOEC system consists of three components: a fuel electrode, which is the green part, an electrolyte, which is the white part, and an oxygen electrode, which is the black part. These components are sandwiched by metallic separators, and cells are stacked up into a cell stack.
Let me explain the reaction mechanism in more detail. Steam is fed into the fuel electrode, which is energized to electrolyze water and generate hydrogen. The O2− ions generated by electrolysis are transported to the oxygen electrode and discharged.
What knowledge is required to develop cell stacks? A knowledge of chemical reaction engineering and electrochemistry is required to develop the electrodes to ensure smooth electrolytic reactions.
Next, electrolytes, which must smoothly transport ions, require a knowledge of solid-state ionics. As I mentioned earlier, cells are expected to operate stably over the long term, and so analytical chemistry is very important to analyze the deterioration process.
Finally, a knowledge of fluid mechanics is required to attain a uniform gas flow of steam and oxygen into each cell. To maintain the robustness of operation, a knowledge of materials mechanics and heat transfer engineering is very important in order to prevent damage.
These are the requirements for fabricating cell stacks. It is extremely difficult to form the developed structure into the target shape. A knowledge of powder technology, metal engineering, and rheological engineering is used to manufacture cell stacks.
Because developing SOEC cell stacks requires interdisciplinary knowledge, experts are invited from various fields to join the development.