Recycling often just postpones the inevitable end of a product's lifecycle, according to Enrique Gomez, interim associate dean for equity and inclusion and professor of chemical engineering at Penn State. However, Gomez and his team are exploring a new method called cold sintering that could promote true recyclability.
Cold sintering combines powdered materials into dense solid forms at low temperatures, using applied pressure and solvents. "With cold sintering, you can take materials destined for the landfill, combine them into a composite, and recycle that composite again and again without loss in performance," Gomez explained in a May 2 news release.
One application mixes polypropylene plastic waste with ceramics to create construction composites that can undergo multiple recycling cycles with minimal energy and water use. Cold sintering can also repair defects in solid-state battery electrolytes, boosting battery performance and sustainability. The method produces capacitor composites for electric vehicles too, reducing greenhouse gas emissions.
Developed in 2016 by Clive Randall's team at Penn State's Materials Research Institute, cold sintering aligns with the circular economy concept of sustainable material reuse. "We're seeing many other research groups globally adopt cold sintering at universities, national labs and even industry," Randall said. "The diversity of emerging applications is amazing, but Gomez's work establishes a path toward the circular economy — an extremely important strategy for a sustainable future."