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Imagine a future where renewable energy storage is not just efficient but also sustainable, scalable, and ethical. This vision is what drives Charley Thomas, a fifth-year PhD student working on cutting-edge battery technology. From solid electrolytes to sodium-ion batteries, Thomas is tackling some of the most pressing challenges in energy storage.

In her current research with the Ban Surface Science and Engineering Research Group, Thomas works on two distinct projects: stress-testing solid electrolytes and developing cathodes for sodium-ion batteries. While both are pivotal in advancing battery science, each presents its own unique challenges and rewards.

Solid electrolytes are a promising alternative to traditional liquid-based systems in lithium-ion batteries. However, testing them is notoriously complex. “Stress-testing solid electrolytes sucks,” Thomas said. “There’s no perfect method for evaluating their performance.”

One commonly used test involves symmetrical cells, where the same electrode is placed on both sides of the solid electrolyte. Critical current density testing—ramping up the current until a short circuit occurs—is used to evaluate the material's performance. But this method has its flaws. “Critical current density isn’t a true material property. It’s influenced heavily by the experimental setup,” Thomas explained.

Despite these challenges, Thomas is dedicated to refining her methods, even when it involves tedious and high-stakes procedures like dipping electrolyte pellets into molten lithium at 180 C. “It’s frustrating when the pellets shatter during the process, but each failure teaches us something valuable,” she said.

Thomas’ second project, focused on sodium-ion batteries, offers a hands-on approach to cathode development. Sodium-ion technology has the potential to address ethical and material scarcity concerns associated with lithium-based systems, as sodium is far more abundant and affordable.

“What excites me about this project is that I get to start from the ground up,” Thomas shared. Using common salts—sometimes even dietary supplements—she synthesizes particles, cleans and dries them, and assembles them into electrodes for testing.

This process has deepened Thomas’ understanding of battery fundamentals. “Unlike solid electrolyte testing, which uses symmetrical cells, working with cathodes involves real chemical potential differences and redox reactions. It’s helping me truly grasp how batteries work,” she said.

Thomas’ ultimate goal is to contribute to sustainable energy storage systems that could revolutionize how we power our world. While initially drawn to academia for its teaching opportunities, she is now exploring postdoctoral research as the next step.

“Work-life balance is important to me, so I’m reevaluating my long-term plans,” she said. “But no matter where I end up, I want to be part of the shift towards renewable, ethical energy storage.”

As she continues refining solid electrolytes and advancing sodium-ion technology, Thomas’ work embodies the intersection of innovation, sustainability, and first-principles science. “When a project finally works—when a battery has great capacity or lasts a long time—it’s the best feeling,” she said.