What is the Fuel Cell?
Like batteries, fuel cells are energy converters – they use electrochemical reactions to convert the chemical energy stored in the fuel source into electrical energy. Unlike batteries with a fixed charge, a fuel cell does not need to be recharged; it produces electricity, water and heat as long as the fuel is continuously supplied.
A fuel cell consists of two electrodes and an electrolyte membrane. The electrodes are divided into a negative and a positive electrode, sandwiching the electrolyte membrane in between. This system produces energy through a series of chemical reactions that separate electrons from the fuel molecules.
The fuel used in a fuel cell is usually hydrogen. The hydrogen is fed into the positive electrode from one side, while the oxygen is fed into the negative electrode from the other side. At the positive terminal, the hydrogen fuel molecules are separated into protons and electrons, which will flow in different paths to the negative terminal. The electrons travel through a circuit to the negative electrode and produce an electric current; the protons travel through the electrolyte to the negative electrode and once there, the oxygen molecules react with the electrons and protons to produce water molecules.
The fuel cell is a clean energy source whose only by-products are electricity, heat and water. A single fuel cell alone can only produce a few watts of power; therefore, fuel cells can be stacked together to form a fuel cell stack. When fuel cells are stacked together, their output power can vary greatly, from a few kilowatts to several megawatts.
Fuel cells have the flexibility to use many types of fuel. While hydrogen is the most common source of fuel (hence the common name of fuel cells), hydrogen-rich fuels such as natural gas and ammonia are also viable.
Hydrogen: When hydrogen is produced using renewable electricity (e.g. solar, wind and hydroelectric power), the production process can be completely zero carbon emission. Hydrogen fuel cells (i.e. fuel cells fuelled by hydrogen) produce electricity, heat and water without releasing carbon dioxide or other pollutants into the air.
Natural gas: Natural gas is currently still the dominant source of hydrogen production as green hydrogen is not yet available in large scale production. In this case, fuel cells are not completely emission-free, but they do have much lower emissions than other fuels such as oil and coal.
Ammonia: Ammonia is mainly used as a fertiliser in agriculture. In recent years, a number of companies have worked to develop green ammonia, generated by alternative energy sources driving hydrogen production by water electrolysis, which makes it an alternative to low carbon fuels.
Fuel Cell Coating Technology
Cheersonic offers ultrasonic spray coating technologies for fuel cell coating which is ideally suited for carbon-based platinum ink solutions onto catalytic membranes in the manufacture of platinum-based hydrogen fuel cells. Ultrasonics has been used in a host of fuel cell related technologies such as Proton Exchange Membranes (PEM) fuel cells, Gas Diffusion Layers (GDLs), Solid Oxide Fuel Cells, electrodes and electrolyte membranes. Ultrasonic spray technology is ideally suited for spray coating costly materials such as platinum and other precision metals in carbon black ink slurries. These chemistries when applied using ultrasonic nozzles onto Nafion fuel cells are superior to hydraulic deposition, pressing, knife edge and paste printing methods.
