Cone and disc carbon structures offer new pathways for sodium-ion batteries

As international demand for electrical automobiles and renewable vitality storage surges, so does the necessity for reasonably priced and sustainable battery applied sciences. A brand new research has launched an revolutionary resolution that would influence electrochemical vitality storage applied sciences.

The analysis is published within the journal Superior Purposeful Supplies. The work was led by researchers from the Division of Supplies Science and NanoEngineering at Rice College, together with collaborators from Baylor College and the Indian Institute of Science Training and Analysis Thiruvananthapuram.

Utilizing an oil and gasoline business’s byproduct, the group labored with uniquely formed carbon materials—tiny cones and discs—with a pure graphitic construction. These uncommon varieties produced through scalable pyrolysis of hydrocarbons may assist tackle a long-standing problem for anodes in battery analysis: learn how to retailer vitality with components like sodium and potassium, that are far cheaper and extra broadly accessible than lithium.

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

Breaking the graphite barrier

Conventional lithium-ion batteries depend on graphite as an anode materials. Nevertheless, the identical graphite construction fails with regards to sodium or potassium. Their atoms are just too huge and interactions too advanced to slip out and in of graphite’s tightly packed layers.

However by rethinking the form of carbon on the microscopic degree, the group discovered a workaround. The cone and disc buildings provide curvature and spacing that welcome sodium and potassium ions with out the necessity for chemical doping (the method of deliberately including small quantities of particular atoms or molecules to vary their properties) or different synthetic modifications.

“We were surprised to see just how well these pure, curved graphitic structures performed,” mentioned first creator Atin Pramanik, a postdoctoral affiliate in Ajayan’s lab. “Even with out heteroatoms, they allowed for reversible intercalation of sodium ions and did so with minimal structural stress.”

Sturdy, scalable and inexperienced

In lab exams, the carbon cones and discs saved about 230 milliamp-hours of cost per gram (mAh/g) utilizing sodium ions, and so they nonetheless held 151 mAh/g even after 2,000 quick charging cycles. In addition they labored effectively with potassium-ion batteries, however the efficiency wasn’t fairly as robust as with sodium.

Superior imaging methods like cryogenic transmission electron microscopy and solid-state nuclear magnetic resonance confirmed that ions had been getting into and exiting the carbon construction as anticipated and that the fabric held its form over hundreds of charge-discharge cycles.

“This is one of the first clear demonstrations of sodium-ion intercalation in pure graphitic materials with such stability,” Pramanik mentioned. “It challenges the belief that pure graphite can’t work with sodium.”

The implications are wide-ranging. Not solely does this pave the best way for extra reasonably priced sodium-ion batteries, however it additionally reduces reliance on lithium, which is changing into costlier and geopolitically sophisticated to supply. As a result of the cone/disc carbon might be synthesized from oil and gasoline business byproducts, it additionally presents a extra sustainable route for battery anode manufacturing.

A turning level for battery design

Whereas most analysis on this space has centered on arduous carbons or doped supplies, the brand new research marks a pivot in technique—emphasizing morphology over chemical modification.

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

“We’re not just developing a better battery material,” Pramanik mentioned. “We’re offering a real pathway to energy storage that’s cleaner, cheaper and more widely available to all.”