By discovering a way to combine lithium salts with ceramics, researchers in the Penn State College of Engineering and the Penn State Materials Research Institute may have created a new class of materials for longer-lasting batteries. According to researchers, the composite nature of the batteries could make recycling easier, reducing landfill waste.
Enrique Gomez, professor of chemical engineering and materials science and engineering with a co-appointment in the Materials Research Institute, led the team, who published their work in Advanced Functional Materials.
Safe, reliable and high-capacity batteries are needed for electric cars, implantable biomedical devices and storage of power generated by renewable energy sources, such as solar or wind. Discarded batteries also pose a solid-waste problem due to the possibility of toxic heavy metals leaching into the environment, as well as their tendency to cause landfill fires.
The search for 'magical materials'
“Battery materials need to excel in a lot of ways,” Gomez said. “They need to be highly conductive, highly resistant, have good mechanical properties and more. Finding the magical material is really hard. Once we find it, making this magical material recyclable is a crucial challenge.”
Gomez and his team have developed a potential “magical material” through a process called cold sintering, which blends a ceramic and an organic salt to create a new hybrid material. The composite combines the conductive properties of the ceramic with the flexible mechanical properties of the organic salt. The batteries made with this material would be more conductive, last longer and be easier to recycle.
“Using our new approach, you could recover these composite battery materials, grind them up and simply make a new component,” Gomez said.
Cold sintering is the key
The process of traditional sintering turns a powder into a solid via extreme heat of more than 1,000 degrees Celsius. Cold sintering achieves the same result with significantly lower temperatures of only 100 to 200 degrees Celsius. This process was unveiled in a 2016 Advanced Functional Materials paper from a team of Penn State researchers led by Clive Randall, professor of materials science and engineering.
The cold sintering temperatures are below the combustion rate of organic materials. Since organics are not destroyed during cold sintering, this could lead to new types of organic-ceramic hybrid materials, such as the battery materials Gomez and his research team are developing.
Building partnerships for a better environment
Beyond batteries, Gomez said there is endless potential for cold sintering to reduce solid waste and improve the environment. Given that cold sintering is a relatively new process, there is a lot to learn about possible applications. To realize the full positive impact of cold sintering, he believes that researchers need to develop a variety of partnerships.
“For example, to move our research forward, it’s crucial to find collaborators who can develop simulations to help us answer fundamental questions and exploit the tremendous potential for material discovery using cold sintering,” Gomez said.
Gomez also stated that industry partnerships help accelerate technology implementation and quickly move related products to market.
“Historically, innovation in academia is disconnected from industry, making the transition to market long and difficult,” Gomez said. “But I think the potential positive impacts of cold sintering are clear now. The question is how can we, as academics, best reach companies to work with us to develop new materials and products for practical uses.”
Along with Gomez and Randall, other contributors include Wonho Lee, postdoctoral scholar in chemical engineering; Christopher Lyon, former postdoctoral research associate in chemical engineering and current research scientist with Vangate Specialty Chemicals; Joo-Hwan Seo, doctoral candidate in materials science and engineering; Raymond Lopez-Hallman, research assistant in materials science and engineering; Yongjun Leng, associate professor of mechanical engineering; Chao-Yang Wang, professor of mechanical, chemical and materials science and engineering and the William E. Diefenderfer Chair Professor; and Michael Hickner, professor of materials science and engineering, chemical engineering and chemistry.