energy storage

Houston researchers make headway on developing low-cost sodium-ion batteries

Rice's Atin Pramanik and a team in Pulickel Ajayan's lab shared new findings that offer a sustainable alternative to lithium batteries by enhancing sodium and potassium ion storage. Photo by Jeff Fitlow/Courtesy Rice University

A new study by researchers from Rice University’s Department of Materials Science and NanoEngineering, Baylor University and the Indian Institute of Science Education and Research Thiruvananthapuram has introduced a solution that could help develop more affordable and sustainable sodium-ion batteries.

The findings were recently published in the journal Advanced Functional Materials.

The team worked with tiny cone- and disc-shaped carbon materials from oil and gas industry byproducts with a pure graphitic structure. The forms allow for more efficient energy storage with larger sodium and potassium ions, which is a challenge for anodes in battery research. Sodium and potassium are more widely available and cheaper than lithium.

“For years, we’ve known that sodium and potassium are attractive alternatives to lithium,” Pulickel Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor of Engineering at Rice, said in a news release. “But the challenge has always been finding carbon-based anode materials that can store these larger ions efficiently.”

Lithium-ion batteries traditionally rely on graphite as an anode material. However, traditional graphite structures cannot efficiently store sodium or potassium energy, since the atoms are too big and interactions become too complex to slide in and out of graphite’s layers. The cone and disc structures “offer curvature and spacing that welcome sodium and potassium ions without the need for chemical doping (the process of intentionally adding small amounts of specific atoms or molecules to change its properties) or other artificial modifications,” according to the study.

“This is one of the first clear demonstrations of sodium-ion intercalation in pure graphitic materials with such stability,” Atin Pramanik, first author of the study and a postdoctoral associate in Ajayan’s lab, said in the release. “It challenges the belief that pure graphite can’t work with sodium.”

In lab tests, the carbon cones and discs stored about 230 milliamp-hours of charge per gram (mAh/g) by using sodium ions. They still held 151 mAh/g even after 2,000 fast charging cycles. They also worked with potassium-ion batteries.

“We believe this discovery opens up a new design space for battery anodes,” Ajayan added in the release. “Instead of changing the chemistry, we’re changing the shape, and that’s proving to be just as interesting.”

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A View From HETI

Rice University's László Kürti has been researching a molecule known as N4 that releases large amounts of energy. Photo by Jeff Fitlow/ Courtesy Rice University.

Rice University chemistry professor László Kürti was named as a recipient of the 2025 Ross M. Brown Investigator Award from the California Institute of Technology’s Brown Institute for Basic Sciences.

Kürti is one of eight mid-career faculty members to receive up to $2 million over five years for their research in the physical sciences.

“I’m greatly honored,” Kürti said in a news release. “We will learn a tremendous amount in the next five years and gain a much clearer understanding of the challenges ahead.”

Kürti was selected for the research he’s been developing for six years on a molecule called tetrahedral N4, which studies show can release large amounts of energy on demand. The molecule can also decompose directly into nitrogen gas without producing carbon dioxide or water vapor. Kürti believes N4 can be used as a "new type of fuel for vehicles."

“Eventually, N4 and other stable, neutral polynitrogen cages could be used to power rockets, helping us reach the moon or Mars faster and with heavier payloads,” he added in this release.

The Brown Investigator Awards were founded by entrepreneur and Caltech alumnus Ross M. Brown and established by the Brown Science Foundation in 2020. The organization has recognized 21 scientists over the last five years.

“Midcareer faculty are at a time in their careers when they are poised and prepared to make profound contributions to their fields,” Brown said in the news release. “My continuing hope is that the resources provided by the Brown Investigator Awards will allow them to pursue riskier innovative ideas that extend beyond their existing research efforts and align with new or developing passions, especially during this time of funding uncertainty.”

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