Page 26 - Engineering Penn State Magazine: Fall/Winter 2020
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  Cold Sintering
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  Ryan Fair, doctoral candidate in materials science and engineering, conducted research into cold sintering in the lab of the Gomez Group at Penn State.
Building a better
by Jamie Oberdick
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, which published its 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 1,000o Celsius. Cold sintering achieves the same result with significantly lower temperatures of only 100 to 200o 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. n

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