Two people working in the foundry.

Advanced Materials and Manufacturing

The Circular Economy

Reduce. Reuse. Remake. Recover. Renew.

These strategies—the five Rs—are central to a circular economy, one in which the life of any good or material bought, sold, used, and discarded is extended as far as possible to curb extraction, pollution, and waste.

Historically, recycling has been an afterthought in the design and manufacturing processes, resulting in a less efficient use of materials and unnecessary costs. Linear manufacturing (or cradle-to-grave) requires extensive financial investment to disassemble and separate disparate materials. Continued landfilling is a steady component of the process.

Reduce: Use design and manufacturing technologies that lower material, energy, and waste footprints.
Reuse: Instead of basing business on one-off sales, offer subscription, leasing, or sharing models.
Remake: Design products to be more easily repaired or remanufactured into new products.
Recover: Turn by-products into new products or add recycled content to products and packaging.
Renew: Substitute/replace finite materials with renewable ones, and focus on sustainable sourcing.

In contrast, circular manufacturing is a philosophy and practice of extending the useful life of materials and products through design for disassembly and reuse. It’s a vital tool in addressing environmental crises like biodiversity loss, resource scarcity, and pollution.

Currently, only 9 percent of the global economy is circular, but an estimated 30 percent of large corporations have a circular strategy, and more than 75 percent plan to adopt targets that will make their products, processes, or business models more circular in the next few years. And manufacturers around the world are building a business case for a circular strategy.

As the world moves toward a global economy, there is much room for innovation in materials and manufacturing technologies that support a circular strategy, including the use of data-driven and machine-learning approaches. And Michigan Tech is ready to lead the charge.

In carrying out our charge to promote the welfare of Michigan’s industries, Michigan Tech stands among global leaders in experimental and digital design of advanced materials, like the composites materials at the heart of our work for the NASA Space Technologies Research Institute. We are renowned for our capabilities in microfabrication and the manufacture of metal alloys, concrete, composite materials, and wood products.

Researchers looking at notes in a lab.

Michigan Tech’s cleanroom is a Class 1000 softwall cleanroom. Inside is a wet chemical bench, polymer spinner, EVG 620 mask aligner, Nikon Optiphot 200 microscope, vacuum oven, and hotplates. Outside the cleanroom, you’ll find a fume hood for fabrication of porous silicon, a dicing saw, and additional wet bench space.

Reincarnated Batteries

When a battery dies for good, recycling is the most sustainable option. But while nearly all old-style automotive batteries are recycled, that’s not the case with their lithium-ion counterparts.

“There is no plant in the US for recycling lithium-ion batteries,” says Lei Pan, assistant professor of chemical engineering. That’s because there’s no economically viable recycling program, and federal law does not mandate the recycling of spent lithium-ion cells. As a result, people usually just toss them into the garbage. Nevertheless, lithium-ion batteries can be highly problematic in landfills. They contain trace amounts of toxic chemicals, and unless they are fully discharged, batteries have an alarming tendency to catch fire and blow up.

Graphite bubbles.
Graphite bubbles form during froth flotation, a technique used in mining engineering, which forces hydrophobic materials to the top as froth (in this case, graphite), and allows valuable cathode materials to sink to the bottom so they can be recovered and recycled.

Pan and his lab want to change that. They came up with an inventive bench-scale process that earned the student team several awards at the People, Prosperity and the Planet (P3) competition hosted by the US Environmental Protection Agency.

Their process starts by crushing whole batteries, then through several steps inspired by old-school mining techniques, they separate out all the materials, including graphite, lithium oxides, plastics, and steel casings. When they are sorted and cleaned, the components can be remade into new batteries or recycled for other uses.

“We are developing separation technologies with a goal of producing high-purity reusable battery materials from waste lithium-ion batteries.”

Lei Pan portrait.
Lei Pan
Chemical Engineer, Department of Chemical Engineering

“A similar process has been used to recycle lead automotive batteries for about a 100 years,” Pan says. More than 99 percent of lead batteries are recycled, according to Battery Council International, and the average lead battery is made of more than 80 percent recycled material, from lead and plastic to sulfuric acid. The near-perfect recycling rate comes from industry investment in a system that keeps 1.7 million tons of batteries out of landfills each year.

“We are applying the same model to the lithium-ion battery,” Pan says. “The idea is simple. It’s just a matter of making sure everything works.”

Continuing his work, Pan is the lead researcher at Michigan Tech on the US Department of Energy’s ReCell Center, the department’s first lithium-ion battery recycling research and development center.