Financial Times: Cells provide fuel for thought

By paul taylor: Published: November 7 2006 02:00 | Last updated: November 7 2006 02:00

For most of the past 167 years, ever since Welsh scientist Sir William Robert Grove built the first fuel cell, they have been little more than laboratory curiosities or confined to military uses and the Nasa space programme.

But now it seems scientists are edging towards their goal of being able to produce practical, safe and low-cost fuel cells capable of powering everything from mobile phones and laptop PCs to electric vehicles.

Several recent developments, including the recall of nearly 10m Sony-manufactured lithium ion laptop batteries because of a fire risk, has focused attention on alternative energy sources, including fuel cells.

As Ed Wall, the US Department of Energy’s programme manager for the FreedomCAR project, noted a few weeks ago, fuel cells, which use hydrogen as a fuel and emit water vapour, present perhaps the best long-term opportunity of creating vehicles that emit no particle pollutants and consume no petroleum.

With a rise in petrol prices last year and growing environmental concerns, that is a compelling vision for car buyers. “We hope that consumer demand, particularly with what we think is a long-term, upward trend in petroleum prices, will drive demand for advanced technologies,” Mr Wall said.

Because they produce very clean energy and are twice as fuel-efficient as conventional internal combustion engines, fuel cells are of great interest to car makers. In fact, virtually every big car producer has a significant research programme focused on fuel cells, and some forecast that cars powered by fuel cells could be available by the end of the decade.

Nevertheless, as Mr Wall and others attending the Department of Energy’s Opportunity Forum last month noted, fuel cell technology and alternative fuels require a lot of work if they are to provide an alternative to oil dependence.

Since fuel cells convert fuel directly and continuously into electricity through electrochemical reactions, they are much more efficient than turbine-based power stations – between 40 to 60 per cent efficient compared with about 20 to 30 per cent for a traditional power station.

Most fuel cells use hydrogen as fuel. The hydrogen is split into protons and electrons by the catalyst – a critical component in fuel cells that speeds up hydrogen conversion. The protons pass through a membrane and combine with electrons from oxygen to generate electricity and water.

But fuel cells have tended to be both bulky and expensive and, while it is possible to extract hydrogen from gasoline using catalysts, the resulting hydrogen is usually contaminated with carbon monoxide and other contaminants that can poison the fuel cell.

In addition, puttinghydrogen-based fuel cells in cars and other consumer products creates a potential safety hazard.

Overcoming challenges such as these has been the focus of fuel cell research over the past decade and attracted the attention of two teams of scientists at the Worcester Polytechnic Institute in Massachusetts.

One team, led by Ravindra Datta, professor of chemical engineering at WPI and director of its Fuel Cell Center, has been investigating fuel cells that use other fuels or that can locally convert more conventional fuels such as natural gas or methane into hydrogen suitable for fuel cells.

“Fuel cells are currently of great interest as low-polluting, high-efficiency power sources for potential applications ranging from the laptop to the automobile,” says Prof Datta.

To make fuel cells that are more tolerant of carbon monoxide, Prof Datta and the team have been trying to develop more robust electrode catalysts and high performance proton-exchange membranes for fuel cells using carbon cloth and Nafion, a high-tech plastic membrane that conducts protons, which is then coated with platinum particles to act as the catalyst.

A key challenge, says Prof Datta, is to make the membrane as thick and as strong and, therefore, as durable as possible without reducing its ability to conduct electricity.

Researchers are also focusing on using watery ethanol, a renewable organic fuel made from biomass, as a fuel. Watery ethanol is less expensive to produce than fuel-grade ethanol, and can produce a clean stream of hydrogen at relatively low temperatures.

Another team at WPI, led by Yi Hua Ma, has been working for more than a decade to overcome another obstacle to the widespread use of fuel cells – the high cost of producing hydrogen pure enough to power the cells without poisoning their catalysts.

Funded in part by a $3m grant from Shell Exploration and Production and Shell Hydrogen over the past six years, Prof Ma, the director of WPI’s Center for Inorganic Membrane Studies, has developed the technology for producing very pure hydrogen from natural gas.

His approach to hydrogen production uses an ultra-thin palladium membrane inside a reactor. The highly efficient membrane allows only the hydrogen to pass through, while high-pressure carbon dioxide, the other primary product of the reaction, can be stored or used in other processes. The process for building the membrane, which can be as thin as 10 microns, was patented by Prof Ma’s team in late 2001.

Prof Ma says the technology offers several advantages over existing hydrogen production systems. For one, the reactor can operate at much lower temperatures than conventional reactors. “Now you can put it in a gas station,” says Prof Ma, whose team has recently handed the technology over to Shell.

So just how soon will fuel cells start showing up in cars and consumer products? Prof Datta and Prof Ma acknowledge that fuel cells have been “just around the corner” for some time and are therefore cautious about predicting when fuel cell or hydrogen-powered cars and consumer products will become commonplace.

Nevertheless, Prof Datta says confidently that, “eventually, consumers will use fuel cells for everything from an iPod to a car”. As the technical barriers to producing safe and efficient fuel cells fall, it becomes simply a matter of economics.

Copyright The Financial Times Limited 2006

This website and sisters royaldutchshellgroup.com, shellnazihistory.com, royaldutchshell.website, johndonovan.website, and shellnews.net, are owned by John Donovan. There is also a Wikipedia segment.