Susanna Thon and Sara Thoi are shedding light on the next generation of batteries—literally.
Their work developing photobatteries, batteries that can recharge themselves in sunlight, has the potential to revolutionize sustainable off-grid power. It also supports two of the primary goals of Johns Hopkins University’s Climate Action and Sustainability Plan—to lead the way in the development of innovative climate solutions through research, scholarship, and teaching and to develop the next generation of climate and sustainability leaders.
“You can always get a solar cell and a battery and hook them together, but the problem with doing that is often the efficiency-to-weight ratio,” says Thon, an associate professor of electrical and computer engineering. “You end up getting these big bulky systems and system complexity. We’re trying to do everything in one device.”
Thon and Thoi, associate professor of chemistry at JHU, are also teaming up to develop flexible colloidal quantum dot-based solar cells, which can be “spray painted” onto batteries to absorb surrounding visible and near-infrared light. If paired with metal organic frameworks (a class of coordination polymers with charge storage capability), both charge generation and storage could exist in one neat, tidy, and sustainable package.
This report highlights JHU’s performance during the 2024 calendar year “[Thoi’s] a battery expert, I’m more of a solar cell person,” Thon says. “When we get faculty candidates coming through and interviewing, this is always one of the things that I say is the best about Hopkins that I haven’t seen as much at other universities: Hopkins really encourages interdepartmental and even inter-school collaboration. And they put their money where their mouth is.”
Thon is no stranger to these types of collaborations. On top of the photobatteries, she’s been working with Yayuan Liu, assistant professor of chemical and biomolecular engineering, to create a passive system of solar cells that captures carbon dioxide from the air. She helped Hopkins and Morgan State University launch the Center for Advanced Electro-Photonics with 2D Materials, which supports her research into ultra-lightweight, flexible solar cells. And then there’s her work as associate director of the Ralph O’Connor Sustainable Energy Institute, where she oversees education and outreach efforts.
Thon also worked with associate research professor Charbel Rizkis to invent a more flexible, lightweight, and effective light-emitting diode (LED) array. This invention was one of 13 JHU projects related to climate or energy innovation to receive a patent in 2024, a key step in eventually bringing the technology to market. It’s also emblematic of a burgeoning innovation ecosystem in climate science and energy systems at the university that is developing creative solutions to a range of planetary health and climate challenges.
“At Hopkins, I found many like-minded people,” Thon says. “The students are super motivated around topics like sustainability. This is what gives me real, actual hope for the future: The young people are passionate and totally committed to things like solving the climate crisis.”