Kenis scales down to power up

The advancements wrought by the unremittent scaling down of transistors are obvious to anyone who uses a cell phone, portable music player, or laptop - and that includes most Americans these days. Beckman Institute researcher Paul Kenis believes the miniaturization of chemical processes could change the way some of those electronic devices are powered.

The advancements wrought by the unremittent scaling down of transistors are obvious to anyone who uses a cell phone, portable music player, or laptop - and that includes most Americans these days. Beckman Institute researcher Paul Kenis believes the miniaturization of chemical processes could change the way some of those electronic devices are powered.

Kenis is considered a pioneer in the miniaturization of chemical processes and the exploration of microscale phenomena involved with those processes because of his approach to developing microchemical systems. Rather than downscaling macroscale systems, Kenis and his group exploit characteristics like microscale flow properties that aren't found at the macro level to create microchemical systems with exciting potential applications in technologies such as fuel cells, pharmaceutical screening chips, and tools aimed at answering biological questions.

Kenis has gained national attention for his pioneering work in membraneless fuel cells and ceramic microreactors. His work on laminar flow fuel cells converged several years ago with that of former Institute researcher Larry Markoski. The Beckman-funded effort eventually led to a start-up company, INI Power Systems, that is now commercializing laminar flow fuel cells for the marketplace. The company's motto "powering the wireless age" is an apt description for a good portion of Kenis' work.

Although Kenis' research seeks to understand certain fundamental scientific questions, it's hard not to imagine the benefits of its potential applications. A ceramic microreactor that can produce hydrogen for hydrogen fuel cells or a membraneless fuel cell that is more environmentally friendly and longer-lasting than current battery technology seem to be the perfect types of power sources needed for an on-demand world.

"It's all related to how can one turn this liquid fuel into electrical energy," Kenis said.

Fuel cells work in the same manner as batteries by turning chemical energy into electrical energy. In 2003, Kenis and Markoski debuted a membraneless fuel cell that uses laminar flow, a flow pattern that at the microscale allows liquids such as the fuels and oxidants used in fuel cells to move in parallel streams with little or no mixing.

The ability of the Kenis group's fuel cell to operate without a solid membrane separating liquids makes for fewer parts and eliminates performance problems found in current alkaline cells such as low conductivity and carbonates clogging the membrane. Kenis believes the membraneless alkaline fuel cell will outperform acidic fuel cells, and could be in demand once laminar flow fuel cells have been integrated in a complete power source. INI Power Systems, with Markoski as president and chief technical officer, is producing a 20-watt prototype demonstrating its direct methanol laminar flow fuel cell developed with the University of Illinois. Kenis said the fuel cell being developed there is expected to have environmental and efficiency advantages over competing fuel cell and battery technologies.

"Present fuel cells work but most of the issues they still have are related to the membrane," he said. "We threw those membrane constraints out the window."

In another breakthrough announced just last month, Kenis and his collaborators reported the creation of a ceramic microreactor for the reforming of hydrocarbon fuels for use in hydrogen fuel cells. Kenis said that even though the development of hydrogen fuel cells is farther along than that of the alkaline fuel cells, they still suffer problems that prevent them from being widely introduced into the market.

"Hydrogen fuel cells are well-developed but storing or carrying hydrogen around in a portable application or in a car, that's a different story," Kenis said. "What you can carry around easily is liquid fuels: ammonia, propane, gasoline, things like that. So if you can turn that liquid fuel into hydrogen using a fuel reformer, you're in business.

"The issue with the reforming of hydrocarbons is the formation of soot, which cokes up the reactor. We can avoid that completely by operating at high temperatures, up to 1000°C. Most other catalyst supports fail at these temperatures."

The ceramic microreactor could be especially useful for off-the-grid power sources in remote locations and for on-site rechargers for battery packs such as those used in the armed forces.

Kenis, a member of Beckman's 3-D Micro and Nanosystems group, came to the University of Illinois in 2000 and immediately began doing fuel cell research as a Beckman faculty member. He has other research areas such as microfluidic tools that facilitate the study of protein dynamics and cell biology, as well as a microreactor that efficiently regenerates cofactors for biocatalytic processes in the production of chiral fine chemicals.

Kenis is also part of a Beckman seed proposal involving tissue engineering for articular cartilage regeneration as part of his more recent efforts in the creation of engineered platforms for cell biology studies. His fuel cell efforts have a much longer history. He became involved in that research line for a number of reasons.

"I was looking for topics for research proposals that would map on an area of interest to society," Kenis said. "There are environmental benefits and fuel cells in general are more efficient than some other ways of creating power. In addition, fuel cell-based power sources have a higher specific energy, and thus last longer than batteries."

Kenis' work, which melds chemistry, biology, materials science, and engineering, is a model of interdisciplinary research. His Web page at the Department of Chemical & Biomolecular Engineering touts the value of the approach: "... some of the best opportunities for research come at the borders between existing fields ..." Kenis said places like Beckman allow researchers to go beyond what they could do working in just one department.

"I would probably not be here if it weren't for the environment that allows you to do this kind of stuff," Kenis said. "I'm very pleased here. The department has been good to me. There are low barriers between units, strength across the board on campus, and many people that want to do interdisciplinary research. So those are ingredients that are really strong at the U of I."