Researchers at Michigan State University find new techniques to increase durability in circuitry used in energy production and space exploration

A research team led by Michigan State University Associate Professor Jason Nicholas is using nickel and silver to produce circuitry that is more heat resistant than what is currently used, which will improve the performance and durability of machinery used in space exploration, energy production, and automobiles. The work is being funded by the U.S. Department of Energy Solid Oxide Fuel Cell Program. The MSU Innovation Center is working on obtaining patents for the process in order to allow the university to commercialize the new technology.

Fuel cells combine fuels with oxidizers, converting chemical energy into electrical energy. A Solid Oxide Fuel Cell (SOFC), one of over a dozen types of fuel cells, is a way of producing energy with very low emissions and minimal resource consumption. As explained in a news release from MSU by Professor Nicholas, "Solid oxide fuel cells work with gases at high temperature. We're able to electrochemically react those gases to get electricity out and that process is a lot more efficient than exploding fuel like an internal combustion engine does."

The innovation developed by Nicholas and his team increases the durability of SOFCs by modifying the process by which circuitry is built, adding a layer of nickel between the ceramic and silver components. The addition of nickel increases the ability of the cells to withstand extreme temperatures. Nicholas described the conditions that the new process addresses, "These devices commonly operate around 700 to 800 degrees Celsius, and they have to do it for a long time — 40,000 hours over their lifetime,” Nicholas said. "For comparison, that's approximately 1,300 to 1,400 degrees Fahrenheit, or about double the temperature of a commercial pizza oven. And over that lifetime, you're thermally cycling it. You're cooling it down and heating it back up. It's a very extreme environment. You can have circuit leads pop off."

The Nicholas Research Group performed computer simulations and experiments to study how the materials interact, and found that the most effective technique was to apply a thin, porous layer of nickel to ceramic before adding the silver which promotes conductivity. "It's the same screen printing that's used to make T-shirts," Nicholas said of the process. "We're just screen-printing electronics instead of shirts. It's a very manufacturing-friendly technique."

Once the nickel is in place on a piece of circuitry, the silver is applied at a temperature of around 1,000 degrees Celsius, a temperature withstood by nickel, allowing the liquified silver to be distributed uniformly through a process called capillary action. "It's almost like a tree. A tree gets water up to its branches via capillary action. The nickel is wicking up the molten silver via the same mechanism," Nicholas said.

Jon Debling of the MSU Innovation Center said of the technology and its application potential, "There are a wide variety of electronic applications that require circuit boards that can withstand high temperatures or high power. These include existing applications in automotive, aerospace, industrial and military markets, but also newer ones such as solar cells and solid oxide fuel cells."

Debling is working on obtaining patents for the new process, while Nicholas looks forward to the future, using the techniques developed by his team, saying, "We're working to improve their reliability here on Earth - and on Mars."

In fact, NASA already uses a solid oxide electrolysis cell technology on the Perseverance Rover to produce oxygen from the gases in the atmosphere on Mars. Nicholas is hopeful that the process developed by his team will increase the potential for scientists to further explore the possibility of generating enough oxygen on Mars to support manned exploration.