3/4/2026 Taylor Parks
Written by Taylor Parks
MechSE Assistant Professor Lili Cai was recently awarded an Illinois Innovation Voucher for her proposal, “Passive Daytime Radiative Cooling (PDRC) Scale-Up and Testing,” a collaborative project between her research group and the startup, SolarMantle Inc, that she co-founded in 2025.
The Illinois Innovation Voucher Program, administered by the Illinois Science & Technology Coalition (ISTC) in partnership with the Illinois Department of Commerce & Economic Opportunity (DCEO), provides funding for applied R&D partnerships between Illinois institutes of higher education and small- and medium-sized enterprises (SMEs). Through these partnerships, the program helps SMEs access specialized expertise, technical capabilities, and research infrastructure to advance product development, validate technologies, and move innovations closer to commercialization, strengthening Illinois’ industrial base and driving economic growth statewide.
Cai’s research group focuses on leveraging thermal science and materials engineering to develop innovative energy and wearable technologies. Over the last several years, her team has advanced fundamental and applied research in passive daytime radiative cooling, resulting in several leading journal publications and patented technologies aimed at reducing energy consumption in the built environment.
“Our material can be applied to any enclosure—commercial or residential buildings, transportation vehicles, or industrial infrastructure,” Cai said. “The film essentially acts as a heat shield by rejecting sunlight and emitting thermal radiation.”
The film offers two key benefits, preventing the direct solar heating of a structure’s surface while simultaneously releasing heat through thermal radiation.
“Many existing materials do not mitigate heat radiation effectively, which is why they can get really hot in the sun,” Cai said. “When applied to common building and infrastructure surfaces, our film helps radiate the heat away rather than allowing it to build up.”
In earlier, laboratory-scale research, Cai’s research group demonstrated films with areas of roughly 10 square centimeters. Building on this foundation, the team transitioned from batch-scale lab fabrication to pilot-scale, continuous extrusion of film roles in widths ranging from six inches to six feet. These efforts enabled scalable manufacturing, which is supported in part by the Illinois Innovation Voucher.
Cai’s Illinois Innovation Voucher application was one of few selected for funding this year from a competitive pool. “The main goal of the project is to optimize our scaled-up product with the support of university research facilities, and use modeling to estimate its potential energy savings in field trials,” she said.
Cai’s path toward commercialization began in 2024 through Chevron Studio, a program in partnership with Chevron Technology Ventures and the National Laboratory of the Rockies. Through this process, Cai and her team co-founded their SolarMantle, for which Cai serves as Chief Scientific Advisor. Sanjeev Kalyanaraman, an experienced entrepreneur who matched with Cai through Chevron Studio, leads the company as CEO, and MechSE alum Aman Mehta (BSME 2024), formerly an undergraduate research intern in Cai’s lab, serves as principal engineer.
SolarMantle has received national recognition through xTechSearch 9, a U.S. Army innovation competition during which the company was selected for a Small Business Innovation Research (SBIR) Phase I award to advance and validate its passive daytime radiative cooing technology. The award supports continued technical development and reflects the technology’s potential relevance to both commercial and defense applications.
“These grants will accelerate commercialization and help demonstrate the technology’s potential to make a meaningful impact on energy,” she said.