Perfect fuel cells with imperfect graphene

An imperfect graphene structure with tiny holes could lead to improved fuel cells.

05/11/2015


The major challenge in fuel cell technology is efficiently separating protons from hydrogen. In a study of single-layer graphene and water, researchers at Northwestern University found that slightly imperfect graphene shuttles protons—and only protons—from one side of the graphene membrane to the other in seconds. The membrane's speed and selectivity are much better than that of conventional membranes, offering engineers a new and simpler mechanism for fuel cell design.

"Imagine an electric car that charges in the same time it takes to fill a car with gas," said chemist Franz M. Geiger, who led the research. "And better yet—imagine an electric car that uses hydrogen as fuel, not fossil fuels or ethanol, and not electricity from the power grid, to charge a battery. Our surprising discovery provides an electrochemical mechanism that could make these things possible one day."

Defective single-layer graphene, it turns out, produces a membrane that is the world's thinnest proton channel—only one atom thick.

"We found if you just dial the graphene back a little on perfection, you will get the membrane you want," said Geiger, a professor of chemistry in the Weinberg College of Arts and Sciences. "Everyone always strives to make really pristine graphene, but our data show if you want to get protons through, you need less perfect graphene."

In the atomic world of an aqueous solution, protons are pretty big, and scientists don't believe they can end up driven through a single layer of chemically perfect graphene at room temperature. (Graphene is a form of elemental carbon composed of a single flat sheet of carbon atoms arranged in a repeating hexagonal, or honeycomb, lattice.)

When Geiger and his colleagues studied graphene exposed to water, they found protons were moving through the graphene. Using cutting-edge laser techniques, imaging methods and computer simulations, they set out to learn how.

The researchers discovered that naturally occurring defects in the graphene—where a carbon atom is missing—triggers a chemical merry-go-round where protons from water on one side of the membrane shuttle to the other side in a few seconds. Their advanced computer simulations showed this occurs via a classic "bucket-line" mechanism first proposed in 1806.

The thinness of the atom-thick graphene makes it a quick trip for the protons, Geiger said. With conventional membranes, which are hundreds of nanometers thick, proton selection takes minutes—much too long to be practical.

Next, the research team asked the question: How many carbon atoms do we need to knock out of the graphene layer to get protons to move through? Just a handful in a square micron area of graphene, the researchers said.

Removing a few carbon atoms results in others being highly reactive, which starts the proton shuttling process. Only protons go through the tiny holes, making the membrane very selective.

"Our results will not make a fuel cell tomorrow, but it provides a mechanism for engineers to design a proton separation membrane that is far less complicated than what people had thought before," Geiger said. "All you need is slightly imperfect single-layer graphene."

Gregory Hale is the editor and founder of Industrial Safety and Security Source (ISSSource.com), a news and information website covering safety and security issues in the manufacturing automation sector. This content originally appeared on ISSSource. Edited by Joy Chang, Digital Project Manager, CFE Media, jchang@cfemedia.com.



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
GAMS preview, 2018 Mid-Year Report, EAM and Safety
June 2018
2018 Lubrication Guide, Motor and maintenance management, Control system migration
May 2018
Electrical standards, robots and Lean manufacturing, and how an aluminum packaging plant is helping community growth.
April 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
SCADA standardization, capital expenditures, data-driven drilling and execution
June 2018
Machine learning, produced water benefits, programming cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
Choosing an automation controller, Lean manufacturing
February 2018
Setting internal automation standards

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Material Handling
This digital report explains how everything from conveyors and robots to automatic picking systems and digital orders have evolved to keep pace with the speed of change in the supply chain.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me