Air-fuelled Battery Could Last Up to 10 Times Longer

Diagram of the STAIR (St Andrews Air) cell. Oxygen drawn from the air reacts within the porous carbon to release the electrical charge in this lithium-air battery. A new type of air-fuelled battery could give up to ten times the energy storage of designs currently available. This step-change in capacity could pave the way for a new generation of electric cars, mobile phones and laptops. The research work, funded by the Engineering and Physical Sciences Research Council (EPSRC), is being led by researchers at the University of St Andrews with partners at Strathclyde and Newcastle. The new design has the potential to improve the performance of portable electronic products and give a major boost to the renewable energy industry. The batteries will enable a constant electrical output from sources such as wind or solar, which stop generating when the weather changes or night falls. An early demonstration model of the STAIR (St Andrews air) cell. Improved capacity is thanks to the addition of a component that uses oxygen drawn from the air during discharge, replacing one chemical constituent used in rechargeable batteries today. Not having to carry the chemicals around in the battery offers more energy for the same size battery. Reducing the size and weight of batteries with the necessary charge capacity has been a long-running battle for developers of electric cars. The STAIR (St Andrews Air) cell should be cheaper than today’s rechargeables too. The new component is made of porous carbon, which is far less expensive than the lithium cobalt oxide it replaces. This four-year research project, which reaches its halfway mark in July, builds on the discovery at the university that the carbon component’s interaction with air can be repeated, creating a cycle of charge and discharge. Subsequent work has more than tripled the capacity to store charge in the STAIR cell. Principal investigator on the project, Professor Peter Bruce of the Chemistry Department at the University of St Andrews, says: “Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries. Our results so far are very encouraging and have far exceeded our expectations.” Cells used in the laboratory to investigate the lithium-air cell. “The key is to use oxygen in the air as a re-agent, rather than carry the necessary chemicals around inside the battery,” says Bruce. The oxygen, which will be drawn in through a surface of the battery exposed to air, reacts within the pores of the carbon to discharge the battery. “Not only is this part of the process free, the carbon component is much cheaper than current technology,” says Bruce. He estimates that it will be at least five years before the STAIR cell is commercially available. The project is focused on understanding more about how the chemical reaction of the battery works and investigating how to improve it. The research team is also working towards making a STAIR cell prototype suited, in the first instance, for small applications, such as mobile phones or MP3 players. Notes for Editors The four-year research project “An O2 Electrode for a Rechargeable Lithium Battery” began on 1 July 2007 and is scheduled to end on 30 June 2011. It has received EPSRC funding of £1,579,137. Rechargeable lithium batteries are currently comprised of a graphite negative electrode, an organic electrolyte and lithium cobalt oxide as the positive electrode. Lithium is removed from the layered intercalation compound (lithium cobalt oxide) on charging and re-inserted on discharge. Energy storage is limited by the lithium cobalt oxide electrode (0.5 Li/Co, 130 mAhg-1). The University of St Andrews design replaces the lithium cobalt oxide electrode with a porous carbon electrode and allows Li+ and e- in the cell to react with oxygen from the air. Initial results from the project found a capacity to weight ratio of 1,000 milli-amp / hours per gram of carbon (mA/hours/g), while recent work has obtained results of up to 4,000 mA/hours/g. Although the two designs work very differently, this equates to an eight-fold increase compared to a standard cobalt oxide battery found in a mobile phone. The application to renewable energy could help get round the problems of intermittent supply. By discharging batteries to provide electricity and recharging them when the wind blows or sun shines, renewables become a much more viable option. The Engineering and Physical Sciences Research Council (EPSRC) is the UK’s main agency for funding research in engineering and the physical sciences. The EPSRC invests around £740 million a year in research and postgraduate training, to help the nation handle the next generation of technological change. The areas covered range from information technology to structural engineering, and mathematics to materials science. This research forms the basis for future economic development in the UK and improvements for everyone’s health, lifestyle and culture. EPSRC also actively promotes public awareness of science and engineering. EPSRC works alongside other Research Councils with responsibility for other areas of research. The Research Councils work collectively on issues of common concern via Research Councils UK. Website address for more information on EPSRC: For more information contact: The University of St Andrews visit: www.st-andrews.ac.uk Professor Peter Bruce FRS, tel: 01334 463 825, e-mail: p.g.bruce@st-andrews.ac.uk Three images are available from the EPSRC Press Office (contact: Matthew.Thompson@epsrc.ac.uk, tel: 01793 4514)

Iron-based Catalyst To Replace Platinum For Cheaper Hydrogen Fuel Cells

Hydrogen fuel cells need catalysts to accelerate the chemical reactions inside them, but the problem is that they are very expensive because the catalysts are made of precious materials like platinum. The new catalyst is based on iron, nitrogen, and carbon which are far less expensive than platinum which ranges between $1,000 to $2,000 an ounce. Although these three non-precious materials were used for hydrogen fuel cells before, they didn’t react too well making the cells unpractical.

Researchers at the Institut National de la Recherche Scientifique, Quebec have managed to increase the power of the catalyst to 99 amps per cubic centimeter at .8 volts which is 35 times better than previous iron-based catalysts. With just a few improvements the INRS scientists should soon reach the 130 amps per cubic centimeter, which is the minimum amount for hydrogen fuel cell catalysts. According to Jean Pol Dodelet, leader of the INRS team, this iron-based catalyst is just as good as platinum catalysts which means that hydrogen fuel cells will become cheaper, and in time, better.

“We thought nobody would ever meet [the benchmark for hydrogen fuel cells]. For the very first time, a non-precious metal catalyst makes sense,” said Hubert Gasteiger, Professor of Mechanical Engineering at MIT. Gasteiger is only one of the researchers who praised INRS’ breakthrough which is “quite surprising” if it were to quote Radoslav Adzic, researcher and fuel cell catalysts-developer at the Brookhaven National Laboratory.

Although other researchers have tried, the INRS team used a different approach, and they increased the number of the catalytic sites in the iron-based material. They figured that if they would have more active sites, then the number of reactions within the material will increase. These catalytic sites are “obtained” by heating a graphite-like form of carbon called carbon black which reacts and creates “gaps” when in contact with ammonia and iron acetate. Then the researchers used nitrogen atoms to link gaps’ opposite sides which eventually result in active catalytic sites.

According to Dodelet, their iron-based catalyst performs best in PEM fuel cells which work at low temperatures, and feature a high power density. He also said that there are other non-precious metal-based catalysts which work in alkaline cells, however, these catalysts will not operate in an acidic environment like the one found in PEM fuel cells.

“We solved the problem,” said Dodelet, but he admits that the catalyst needs further improvements because it has two major flaws - the former is its durability which has to be increased as after 100 hours, the reactions in the cells were halved; and the latter is the fact that catalysts can operate as fast as the reactants allow them, but the oxygen and protons transportation will have to be improved by fuel cell engineers as Dodelet’s team only develops the catalysts.

I don’t think that it will take too long before these obstacles will be overcome, and it is quite possible that in the near future automakers will get their hands on cheaper hydrogen fuel cells which means that we will be able to buy hydrogen cars at lower prices.

Pepperidge Farm Opens Largest Fuel Cell Plant In United States

Written by Ariel Schwartz

I have Pepperidge Farm to thank for my Goldfish addiction, and now I’d like to thank the company once again for making strides towards sustainability. Earlier today, Pepperidge Farm dedicated the largest fuel cell plant in the United States at its Bloomfield, CT bakery. The 1.2 MW plant will supply 57 percent of the 260,000 square foot facility’s power.

The new plant is Pepperidge Farm’s second foray into fuel cells— the company opened a 250 kW plant in 2006. Together, the two fuel cell plants will provide 70 percent of the bakery’s power. Excess heat from the new fuel cell will be used to support bakery processes, thereby reducing the fuel needs of plant boilers.

Pepperidge Farm’s new DFC fuel cell was built by Fuel Cell Energy, Inc. The cell operates at 47 percent electrical efficiency. When excess heat from the cell is used for bakery processes, it operates at up to 80 percent efficiency. In addition to lowering power costs for the company, the fuel cell will also drastically reduce CO2 emissions from the facility.