Superior high-voltage performance of Li-ion full cell with Li-rich layered oxide cathode prepared with fluorinated polyimide (FPI) binder, compared to the cell with conventional binder PVdF. (Click to enlarge.)
Image: Seung Wan Song

In order to increase the driving range of electric vehicles, researchers across the globe are working to develop lithium-ion batteries with higher energy storage. Now, scientists at Chungnam National University and Kumoh National Institute of Technology in Korea are taking a step toward that goal with their development of the first high-voltage cathode binder for higher energy Li-ion batteries.

Today’s Li-ion batteries are limited to charge to 4.2V due to the electrochemical instability of the liquid electrolyte and cathode-electrolyte interface, and loosening of conventional binder, polyvinylidenefluoride (PVdF), particularly at elevated temperatures. The fabrication of Li-rich layered oxide cathode with a novel high-voltage binder, as the research team demonstrated, can overcome these limitations.

Charging the batteries with Li-rich layered oxide cathode (xLi₂MnO₃∙(1−x)LiMO2, M = Mn, Ni, Co) to higher than 4.5V produces approximately doubled capacity than those with LiCoO₂ cathode, so that doubled energy density batteries can be achieved.

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Lithium-ion batteries supply billions of portable devices with energy. While current Li-ion battery designs may be sufficient for applications such as smartphones and tablets, the rise of electric vehicles and power storage systems demands new battery technology with new electrode materials and electrolytes.

ECS student member Michael Metzger is looking to address that issue by developing a new battery test cell that can investigate anionic and cationic reactions separately.

Along with Benjamin Strehle, Sophie Slochenbach, and ECS Fellow Hubert A. Gasteiger, Metzger and company published their new findings in the Journal of The Elechemical Society in two open access papers.

(READ: “Origin of H₂ Evolution in LIBs: H₂O Reduction vs. Electrolyte Oxidation” and “Hydrolysis of Ethylene Carbonate with Water and Hydroxide under Battery Operating Conditions“)

“Manufacturers of rechargeable batteries are building on the proven lithium-ion technology, which has been deployed in mobile devices like laptops and cell phones for many years,” says Metzger, the 2016 recipient of ECS’s Herbert H. Uhlig Summer Fellowship. “However, the challenge of adapting this technology to the demands of electromobility and stationary electric power storage is not trivial.”

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The liquid metal antenna can be tuned to listen to various frequencies by applying electrical voltage.
Image: Jacob Adams/NCSU

The scientific community has been trying to tap into the potential of liquid metals for some time now, but have faced roadblocks in developing something that is highly efficient when paired with electronics. Now, North Carolina State University researchers have successfully designed a liquid metal antenna controlled by only electrical voltage.

The work is relatively simple in theory. A positive voltage applied to a liquid metal will make it expand, whereas the application of a negative voltage will make it contract.

“Our antenna prototype using liquid metal can tune over a range of at least two times greater than systems using electronic switches,” said Jacob Adams, assistant professor in the Department of Electrical and Computer Engineering at NCSU.

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