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Breakthrough in Battery Technology: An Atomic Look at Lithium-rich Batteries

Batteries have come a long way since Volta first stacked copper and zinc disks 200 years ago.

While the technology has continued to evolve from lead acid to lithium ion,mBatteries have come a long way since Volta first stacked copper and zinc disks 200 years ago.

While the technology has continued to evolve from lead acid to lithium ion, many challenges remain, such as achieving higher density and suppressing dendrite growth.

Experts are rushing to tackle the growing global need for energy-efficient and safe batteries. The electrification of heavy vehicles and aircraft requires batteries with a higher energy density.

A team of researchers believes a paradigm shift is needed to have a significant impact in battery technology for these industries.

This shift would take advantage of the anionic reduction-oxidation mechanism in lithium-rich cathodes. Findings published in Nature mark the first time direct observation of this anionic redox reaction has been observed in a lithium-rich battery material.

Collaborating institutions were Carnegie Mellon University, Northeastern University, Lappeenranta-Lahti University of Technology (LUT) in Finland, and institutions in Japan, including Gunma University, Japan Synchrotron Radiation Research Institute (JASRI), Yokohama National University, Kyoto University, and Ritsumeikan University.

manychallenges remain, such as achieving higher density and suppressing dendrite growth. Experts are rushing to tackle the growing global need for energy-efficient and safe batteries.

The electrification of heavy vehicles and aircraft requires batteries with a higher energy density.

A team of researchers believes a paradigm shift is needed to have a significant impact in battery technology for these industries.

This shift would take advantage of the anionic reduction-oxidation mechanism in lithium-rich cathodes. Findings published in Nature mark the first time direct observation of this anionic redox reaction has been observed in a lithium-rich battery material.

Collaborating institutions were Carnegie Mellon University, Northeastern University, Lappeenranta-Lahti University of Technology (LUT) in Finland, and institutions in Japan, including Gunma University, Japan Synchrotron Radiation Research Institute (JASRI), Yokohama National University, Kyoto University, and Ritsumeikan University.

Lithium-rich oxides are promising cathode material classes because they have been shown to have a much higher storage capacity.

But there is an ‘AND problem’ that battery materials must meet: the material must be able to charge quickly, withstand extreme temperatures and run reliably for thousands of cycles.

Scientists need a clear understanding of how these oxides work at the atomic level and how their underlying electrochemical mechanisms play a role in addressing this.

Normal Li-ion batteries operate through cationic redox, when a metal ion changes its oxidation state when lithium is introduced or removed. Within this insertion framework, only one lithium ion can be stored per metal ion. However, lithium-rich cathodes can store much more.

Researchers attribute this to the anionic redox mechanism – in this case oxygen redox. This is the mechanism attributed to the high capacity of the materials, almost doubling the energy storage compared to conventional cathodes.

While this redox mechanism has emerged as the main competitor among battery technologies, it represents a linchpin in materials chemistry research.

The team wanted to provide conclusive evidence for the redox mechanism using Compton scattering, the phenomenon where a photon deviates from a straight orbit after interacting with a particle (usually an electron).

The researchers conducted advanced theoretical and experimental studies at SPring-8, the world’s largest third-generation synchrotron radiation facility operated by JASRI.

Synchrotron radiation consists of the narrow, powerful beams of electromagnetic radiation produced when electron beams are accelerated to (near) the speed of light and forced into a curved orbit by a magnetic field. Compton scattering becomes visible.

The researchers observed how to image and visualize the electronic orbital that lies at the heart of the reversible and stable anionic redox activity, and how to determine its character and symmetry.

This scientific first could be groundbreaking for future battery technology. Although previous research has suggested alternative explanations for the anionic redox mechanism, it has not been able to provide a clear picture of the quantum mechanical electronic orbitals associated with redox reactions because it cannot be measured with standard experiments.

The research team had an “A ha!” moment when they first saw the similarity in redox character between theory and experimental results.

“We realized that our analysis could provide a picture of the oxygen states responsible for the redox mechanism, which is fundamental to battery research,” explains Hasnain Hafiz, lead author of the study who conducted this work during his time as a postdoctoral fellow. research associate at Carnegie Mellon.

“We have compelling evidence supporting the anionic redox mechanism in a lithium-rich battery material,” said Venkat Viswanathan, an associate professor of mechanical engineering at Carnegie Mellon.

“Our study provides a clear picture of the operation of a lithium-rich battery at the atomic scale and suggests routes for designing next-generation cathodes to enable electric aviation.

The design for high-energy-density cathodes represents the next frontier for batteries. ”