industry and academics are to collaborate on a £2.1m research project to investigate potential barriers to the introduction of fuel cells for vehicles and power generation.
The EPSRC-funded project will examine the obstacles that must be overcome before fuel cells can be fully exploited, including key issues like durability and power density. The research will also investigate the potential of new fuels like ethanol and innovative materials that could allow cells to operate at a wider range of temperatures.
Prof Nigel Brandon, leading the research at
High-temperature solid oxide fuel cells (SOFCs) with ceramic membranes operate at around 1,000°C. Rolls Royce is backing this area of the research, which will focus on reducing operating temperatures, because SOFCs are slow to start up, require heavy shielding and can use only high-temperature parts.
‘There are system benefits and efficiency gains to be won by putting the air and fuel in at a lower temperature, and so reducing the necessary cooling systems for the stack,’ said
The research at
Prof Keith Scott, heading the PEM research at
Fuel type is also a challenge for PEM cell development. Hydrogen is bulky and difficult to store, and so fuels like ethanol would prove more suitable if its power efficiency can be improved.
In addition, the researchers aim to reduce the operating temperature of metallic membrane SOFCs in collaboration with Ceres Power.
How fuel cells work
On one side (the anode side) of the fuel cell is fuel in the form of hydrogen gas, and on the other side (the cathode side) is oxygen (in air). Sandwiched between the anode and cathode is the very thin, gas tight, electrically insulating but ion conducting, electrolyte layer. An electrical circuit connects the anode to the cathode and provides the mechanism to power electrical devices.
The combination of the materials used to make the fuel cell components, the type of fuel used and the operating temperature allow electricity to be generated via a chemical reaction rather than burning the fuel. The reaction starts with the oxygen on the cathode side being ionised at the cathode and generating negatively charged oxygen ions that then flow through the cathode and across the electrolyte.
At the anode side the oxygen ion combines with a positively charged hydrogen ion and releases an electron that then, because of the charge imbalance and the electron-impermeable electrolyte, flows around the electrical circuit to the cathode side generating direct current. This direct current will continue to be produced as long as there is a supply of fuel and air to the fuel cell. – courtesy Ceres Power.