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Energy Storage

Amazing Women

Amy Prieto is building safer, more powerful batteries

With Prieto Battery, the Colorado State professor has redesigned the lithium-ion battery from the bottom up

by Jyllian Kemsley
March 8, 2020 | A version of this story appeared in Volume 98, Issue 9

This is a photo of Amy Prieto.
Credit: Kira Vos

Born in Colombia to a Colombian father and American mother, Amy Prieto moved to the US when she was nearly 4 years old. “I think early on I appreciated the need to try to learn people’s languages and where they’re coming from,” she says.


Titles: Chief technology officer, Prieto Battery, and professor of chemistry, Colorado State University

Funding for Prieto Battery: $14 million

Investors of Prieto Battery: Intel, Stanley Black & Decker, and angel investors and other individuals

That heritage has served her well as she’s bridged scientific fields, along with academia and industry, to develop battery technology at the heart of her company, Prieto Battery.

Prieto got into batteries after her PhD and postdoc work. During her PhD studies at the University of California, Berkeley, she synthesized solid-state materials, and during her postdoc at Harvard University, she measured electron transport phenomena. “When I started my faculty position, I tried to find problems that would draw from both areas,” she says of joining the faculty at Colorado State University in 2005. As she considered various functional materials to pursue, “I think every application I looked at involved things that were fundamentally limited by the battery.

“At first I thought batteries were old and there wasn’t much to do” in the way of updating them, Prieto says. “Then I realized how messy they are. They really require different materials to work together. It doesn’t matter if you make the best compound ever for one component. If you don’t get them to communicate, then it doesn’t matter.”

Seeing a need for higher-capacity batteries that can charge faster, Prieto drew on her time as a graduate fellow at Bell Labs to tackle the problem.

Career Ladder: Snapshot

Amy Prieto is born in Colombia. At age 3, she moves with her family to Grand Rapids, Michigan.

Early 1990s
At Williams College, she debates pursuing careers in music and philosophy before settling on chemistry.

Prieto works at Bell Labs as a summer research fellow before beginning graduate school. “Bell Labs mixed people intentionally. It wasn’t chemists in one hall and physicists in another,” Prieto says. At lunch, she loved listening to colleagues convince one another to help with projects. “They took the time to learn each other’s languages,” she says.

After a PhD at the University of California, Berkeley, and a postdoc at Harvard University, Prieto joins the faculty at Colorado State University and begins to work on batteries. A synthetic chemist at heart, she says she comes alive when a theorist predicts a good compound or molecular architecture for an application and she thinks, “Oh, I can make that!”

Prieto launches Prieto Battery in 2009. Late last year, one of the firm’s 3-D lithium-ion battery prototypes passed third-party performance testing.

The overall culture at the famous Bell Labs, she says, was one of thinking what success would look like, then working backward to figure out how to get there. “That really influenced how I think about problems,” Prieto says.

In terms of developing novel lithium-ion battery materials and manufacturing processes, that meant understanding trade-offs: for a conventional 2-D battery to store a lot of energy, its electrodes need to be thick, but for it to charge quickly, they need to be thin. Prieto’s 3-D batteries are based on a foam substrate that undergoes two electroplating steps and a coating process to add the anode, a solid-state polymer electrolyte, and a cathode. Because the electroplating coats the foam’s pores and outer surface, the material has greater surface area compared with a conventional battery. That means it simultaneously has greater energy storage capacity and can charge and discharge faster.

Prieto became an entrepreneur through “good fortune,” she says. Colorado State had a program to promote clean energy development by pairing researchers with mentors who had commercialization and entrepreneurial experience. Her 3-D battery research had reached a stage where it would be harder to quickly progress in a university setting, so she founded Prieto Battery in 2009 with funding from an angel investor to purchase better equipment, work on prototypes, and build a pilot manufacturing line.

One of Prieto’s first graduate students, Tim Arthur, helped get the company off the ground and is now a principal scientist at the Toyota Research Institute, North America. As a graduate student he learned the fundamental science—“Amy was always concerned about that,” he says—while also working with people at all stages of product development. “It opened my eyes for my current job,” he says.

A big lesson that Prieto is now learning about industry is when to say something is ready for market. “As an academic scientist, you always know you can make your process or compounds or devices better,” she says. In industry, “when you see that what you have can actually meet a need in a particular market, then you have to say, ‘Good enough.’ ”

One of her battery prototypes, for example, doesn’t store energy at 100% of its theoretical capacity, but it’s safer than conventional models—it can be heated or shorted without igniting. Those are critical qualities for batteries used in medical devices and some military applications, she says, making it worth scaling up and commercializing.

To what behavior or personality trait do you most attribute your success?

"I can’t remember how many times I tried a certain reaction and it failed, but I can always remember the feeling of when it first worked. I think that’s important for a scientist."


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