Japanese tout low-temp fuel cell

Japanese researchers say they've developed a smaller, cheaper fuel cell that can also generate power at room temperatures.

Researchers said the current polymer-electrolyte fuel cell design has low efficiency of power at room temperatures. Researchers plan to tweak the composition and improve its overall power generation for eventual use in a variety of applications, including stationary power, automobiles and mobile devices, within a decade.

Masahiro Rikukawa, professor of the Faculty of Science and Technology at Sophia University, led the research team, which plans to present its findings at the 57th Polymer Symposium at Osaka City University from Sept. 24 to 26.

The domestic market for fuel cells in Japan is expected to be 300 times its current size by 2020—¥1.2 trillion ($11.1 billion), according to new data this week from private research institution Fuji Keizai.

Matsushita Electric Industrial (NYSE:MC) and Nippon Oil are expected to start mass production of polymer-electrolyte fuel cells next fiscal year (see Sanyo, Nippon Oil setting up fuel cell venture and Matsushita to sell home-use fuel cells in 2009), and solid-oxide fuel cells are expected to increase in popularity, Fuji Keizai said.

Those projections assume that cost and durability improve, Fuji Keizai said. The automotive fuel cell market is expected to reach ¥900 billion in 2020, and compact fuel cells for mobile phones and other devices have projected sales of ¥14.5 billion in 2020, Fuji Keizai said.

The researchers’ new fuel cell uses a membrane composed of polybenzimidazole doped with phosphoric acid, allowing protons to migrate through the phosphoric acid. In a typical polymer electrolyte fuel cell using sulfonic acid, protons are carried through water, the researchers said. Researchers said their fuel cell is smaller and cheaper because it eliminates the need for water-control mechanisms.

The research team said manufacturers such as BASF and Volkswagen of Germany have advocated polybenzimidazole-phosphoric acid membranes. But existing technology requires external energy to heat conditions to 100 degrees Celsius or higher to begin generating power.

At room temperature, this new fuel cell gradually heats itself through a chemical reaction until it reaches at least 100 degrees Celsius.

The polymer-electrolyte fuel cell shows ionic conductivity in conditions ranging from room temperatures up to 200 degrees Celsius, higher than the 90 degrees shown by existing polymer-electrolyte fuel cells, researchers said. That characteristic is expected to generate power efficiently and prevent catalyst poisoning.

One drawback, researchers said, is the low power density at room temperatures—8.23 milliwatts per square centimeter at 23 degrees Celsius. Power density reaches 270 to 280 mw/cm² at 160 degrees Celsius. 

Increasing the amount of phosphoric acid increases the power generation efficiency but deteriorates the catalytic performance and eventually lowers efficiency because it can adhere to platinum as it migrates with protons, researchers said.

The researchers plan to experiment with other polymers than polybenzimidazole and to improve the durability of the membrane and power generation by increasing adsorption of phosphoric acid.

The research was sponsored by Japan's New Energy and Industrial Technology Development Organization in a project to develop practical uses for polymer-electrolyte fuel cells. The researchers say the polymer-electrolyte fuel cell’s membrane can also be used for alkaline fuel cells and direct methanol fuel cells.

Cleantech developments making news in the past 24 hours

• AES raises $1.58B with China Investment
• Patently unobvious

View the last week of cleantech developments here | Subscribe to full feed