Zhenxing Feng’s research focuses on the chemical processes involved in energy storage and conversion. Specifically, he is interested in developing and improving devices — such as batteries and fuel cells — instrumental in effecting the world’s transition to clean, sustainable, and renewable energy.
An assistant professor in chemical engineering, Feng came to Oregon State in the fall of 2016 after spending three years as a researcher at the Joint Center for Energy Storage Research at Argonne National Laboratory. Feng says his science background enables him to have a solid grasp of chemistry at the atomic level, but he derives great satisfaction from applying this knowledge to real-world problems on a human scale.
“I started off studying physics, but I really wanted to see applications,” Feng said. “All the work I am doing has the potential to make changes in everyday life. For example, battery technology has become a hot topic lately because of electric cars. This is an area where small details can create a big impact.”
If you want to build a better battery, Feng says, you first need to understand how it works. A big part of Feng’s work focuses on fundamental studies for elaborating the processes at work in existing technologies to identify potential inefficiencies and areas for improvement.
“We try to do things rationally,” Feng says. “If we know, for example, that a cathode is the bottleneck for the development of next-generation battery, we will identify factors that can improve the cathode performance. The best way to diagnose the device is to ‘see’ what is going on inside it during its operation, which is called in situ operando studies.”
These studies often involve trips to national facilities, such as the Advanced Photon Source at Argonne National Laboratory and Advanced Light source at Lawrence Berkeley National Laboratory, where high-flux and bright X-rays are generated to penetrate the working devices (e.g., battery and fuel cells) in a non-destructive way but provide atomic structure and chemical information of materials that researchers are interested in.
“It is like a doctor using a CT scan to examine a patient,” said Feng.
One of Feng’s projects is focused on the development of safe, high-energy-density, lithium-ion batteries with long cycle life for applications both in small electronic devices, such as laptop computers, and in electric cars.
The state-of-the-art lithium ion batteries in today’s electric cars can support a range of only around 100 miles, one-third the range of a typical gasoline-powered car. By using a lithium-conducting thin layer to coat the surface of the battery’s cathode, Feng has improved the energy density more than 30 percent, as the modified cathode can be operated at higher voltage. Furthermore, this improvement elongates the cycle life about two to three times longer than commercial lithium-ion batteries, due to the robust surface protection.
Feng’s research is also looking beyond lithium-ion technologies, including lithium-sulfur batteries, which offer eight times the storage density of current lithium-ion batteries, and solid-state batteries, which eliminate the need for liquid electrolytes and can work under extreme high or low temperatures.
“This could be useful if we want to go to Mars, for example,” Feng said. “However, these advanced technologies have problems in stability and cycle life that will need to be overcome before they can be considered a practical alternative”
In the area of energy conversion, Feng is examining the possibility of using low-cost metal oxides as catalysts in fuel cells to replace precious metals like platinum. A fuel cell is a clean-energy device that uses zero-pollution fuels, hydrogen and oxygen, to generate electricity. Their low efficiency is the key issue that prevents their wide commercialization, and a cost-effective catalyst could be their salvation. Feng is also interested in using catalysts to convert carbon dioxide into useful fuels, which is called the carbon-neutral process.
Feng’s work has received funding support from the Joint Center for Energy Storage Research and the Energy Frontier Research Center of the U.S. Department of Energy. He is the current Callahan Faculty Scholar in Chemical Engineering at Oregon State. In 2017, he was named a Scialog Fellow of Research Corporation for Science Advancement, which recently awarded him a grant for his advanced energy storage research.