Engineers Invent Inks for Making 3-D Printed Fuel Cells

3-D printed fuel cells could come in unusual shapes and sizes

2 min read
Engineers Invent Inks for Making 3-D Printed Fuel Cells
Photo: Shah Tissue Engineering and Additive Manufacturing Lab and Northwestern University

Making ceramic fuel cells with a 3-D printer would be a quick and easy way to manufacture the devices and could lead to new fuel cell designs that do a better job of converting a gas into electricity, according to researchers at Northwestern University.

The lab of Ramille Shah, assistant professor of materials science and engineering, has developed new inks that a single 3-D printer can use to create the individual components of the solid oxide fuel cell—cathode, anode, electrolyte, and interconnects. The inks are a mixture of ceramic particles that make up 70 to 90 percent of the mix, a binder, and a cocktail of solvents that evaporate at different rates. The ink for the electrolyte, for example, is made of yttrium-stabilized zirconia (YSZ) particles, while the anode is YSZ plus nickel oxide.

When the machine prints a line with one of these inks, a highly volatile solvent in the mix evaporates immediately, so the printed piece turns from a liquid to a solid instantly. The other solvents, however, evaporate more slowly, leaving the printed line hard enough to maintain its shape but soft enough that the next layer melds with it to form a single piece. The printing is done at room temperature, but just like when making a ceramic vase, the printed piece has to be fired at up to 1250° C to make it denser and smoother. To make sure the different parts of the printed fuel cell all shrink at the same rate during firing, the team tweaks the composition of the individual inks, and adds iron oxide in some layers.

“We can get really densely packed particles in the printed structure,” says Adam Jakus, a Ph.D. student in Shah’s lab, who described the work at the Materials Research Society’s fall meeting in Boston this week.

Solid-oxide fuel cells operate at high temperatures, so they don’t require catalysts and work with a variety of gases, including methane. They could be used to provide power to the electricity grid.

Using 3-D printing to build fuel cells of a standard design could be an easier manufacturing process than having to join the separate parts together, says Jakus. But, he says, the real promise could come from 3-D printing’s ability to create shapes that standard manufacturing processes can’t. For instance, they’ve printed flat sheets of the ceramic materials, which can be rolled or folded into different shapes before firing. Instead of the standard stack of fuel cells, they could be built in concentric circles, or be interwoven, creating more surface area and therefore easier transport of charge. Jakus, though, focuses on the inks, and will leave it up to colleagues who are experts in fuel cells to experiment with new designs.

Meanwhile, he’s developing similar inks for other uses, such as 3-D printed ceramic bone replacements that mimic the mechanical properties of actual bone. The team has also made an ink that allows 3-D printing of graphene.

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Smokey the AI

Smart image analysis algorithms, fed by cameras carried by drones and ground vehicles, can help power companies prevent forest fires

7 min read
Smokey the AI

The 2021 Dixie Fire in northern California is suspected of being caused by Pacific Gas & Electric's equipment. The fire is the second-largest in California history.

Robyn Beck/AFP/Getty Images

The 2020 fire season in the United States was the worst in at least 70 years, with some 4 million hectares burned on the west coast alone. These West Coast fires killed at least 37 people, destroyed hundreds of structures, caused nearly US $20 billion in damage, and filled the air with smoke that threatened the health of millions of people. And this was on top of a 2018 fire season that burned more than 700,000 hectares of land in California, and a 2019-to-2020 wildfire season in Australia that torched nearly 18 million hectares.

While some of these fires started from human carelessness—or arson—far too many were sparked and spread by the electrical power infrastructure and power lines. The California Department of Forestry and Fire Protection (Cal Fire) calculates that nearly 100,000 burned hectares of those 2018 California fires were the fault of the electric power infrastructure, including the devastating Camp Fire, which wiped out most of the town of Paradise. And in July of this year, Pacific Gas & Electric indicated that blown fuses on one of its utility poles may have sparked the Dixie Fire, which burned nearly 400,000 hectares.

Until these recent disasters, most people, even those living in vulnerable areas, didn't give much thought to the fire risk from the electrical infrastructure. Power companies trim trees and inspect lines on a regular—if not particularly frequent—basis.

However, the frequency of these inspections has changed little over the years, even though climate change is causing drier and hotter weather conditions that lead up to more intense wildfires. In addition, many key electrical components are beyond their shelf lives, including insulators, transformers, arrestors, and splices that are more than 40 years old. Many transmission towers, most built for a 40-year lifespan, are entering their final decade.

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