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 Comparison of cathode volume changes in all-solid-state cells under low-pressure operation. Credit: Korea Institute of Science and Technology

Topics: Batteries, Chemistry, Climate Change, Lithium, Materials Science, Nanomaterials

Often referred to as the "dream batteries," all-solid-state batteries are the next generation of batteries that many battery manufacturers are competing to bring to market. Unlike lithium-ion batteries, which use a liquid electrolyte, all components, including the electrolyte, anode, and cathode, are solid, reducing the risk of explosion, and are in high demand in markets ranging from automobiles to energy storage systems (ESS).

However, devices that maintain the high pressure (10s of MPa) required for stable operation of all-solid-state batteries have problems that reduce the battery performance, such as energy density and capacity, and must be solved for commercialization.

Dr. Hun-Gi Jung and his team at the Energy Storage Research Center at the Korea Institute of Science and Technology (KIST) have identified degradation factors that cause rapid capacity degradation and shortened lifespan when operating all-solid-state batteries at pressures similar to those of lithium-ion batteries. The research is published in the journal Advanced Energy Materials.

Unlike previous studies, the researchers confirmed for the first time that degradation can occur inside the cathode as well as outside, showing that all-solid-state batteries can be operated reliably even in low-pressure environments.

In all-solid-state batteries, the cathode and anode have a volume change during repeated charging and discharging, resulting in interfacial degradation, such as side reaction and contact loss between active materials and solid electrolytes, which increase the interfacial resistance and worsen cell performance.

To solve this problem, external devices are used to maintain high pressure, but this has the disadvantage of reducing energy density as the weight and volume of the battery increase. Research is being conducted on the inside of the all-solid-state cell to maintain the performance of the cell, even in low-pressure environments.

Investigation of the degradation mechanism for all-solid-state batteries takes another step toward commercialization, National Research Council of Science and Technology.

Electric field- and pressure-assisted fast sintering to control graphene alignment in thick composite electrodes for boosting lithium storage performance. Credit: Hongtao Sun, Penn State

Topics: Battery, Energy, Graphene, Green Tech, Lithium, Materials Science, Nanomaterials

The demand for high-performance batteries, especially for use in electric vehicles, is surging as the world shifts its energy consumption to a more electric-powered system, reducing reliance on fossil fuels and prioritizing climate remediation efforts. To improve battery performance and production, Penn State researchers and collaborators have developed a new fabrication approach that could make for more efficient batteries that maintain energy and power levels.

The improved method for fabricating battery electrodes may lead to high-performance batteries that would enable more energy-efficient electric vehicles, as well as such benefits as enhancing power grid storage, according to Hongtao Sun. Sun is an assistant professor of industrial and manufacturing engineering at Penn State and the co-corresponding author of the study, which was published in and featured on the front cover of Carbon.

"With current batteries, we want them to enable us to drive a car for longer distances, and we want to charge the car in maybe five minutes, 10 minutes, comparable to the time it takes to fill up for gas," Sun said. "In our work, we considered how we can achieve this by making the electrodes and battery cells more compact, with a higher percentage of active components and a lower percentage of passive components."

If an electric car maker wants to improve the driving distance of their vehicles, they add more battery cells, numbering in the thousands. The smaller and lighter, the better, according to Sun.

"The solution for longer driving distances for an electric vehicle is just to add compact batteries, but with denser and thicker electrodes," Sun said, explaining that such electrodes could better connect and power the battery's components, making them more active. "Although this approach may slightly reduce battery performance per electrode weight, it significantly enhances the vehicle's overall performance by reducing the battery package's weight and the energy required to move the electric vehicle."

Thicker, denser, better: New electrodes may hold the key to advanced batteries, Jamie Oberdick, Pennsylvania State University, techxplore.

The new composition for fluorine-containing electrolytes promises to maintain high battery charging performance for future electric vehicles even at sub-zero temperatures. (Image by Shutterstock.)

Topics: Battery, Chemistry, Climate Change, Global Warming, Lithium, Materials Science

Scientists developed a new and safer electrolyte for lithium-ion batteries that work as well in sub-zero conditions as it does at room temperature.

Many owners of electric vehicles worry about how effective their batteries will be in very cold weather. Now new battery chemistry may have solved that problem.

In current lithium-ion batteries, the main problem lies in the liquid electrolyte. This key battery component transfers charge-carrying particles called ions between the battery’s two electrodes, causing the battery to charge and discharge. But the liquid begins to freeze at sub-zero temperatures. This condition severely limits the effectiveness of charging electric vehicles in cold regions and seasons.

To address that problem, a team of scientists from the U.S. Department of Energy’s (DOE) Argonne and Lawrence Berkeley national laboratories developed a fluorine-containing electrolyte that performs well even in sub-zero temperatures.

“Our research thus demonstrated how to tailor the atomic structure of electrolyte solvents to design new electrolytes for sub-zero temperatures.” — John Zhang, Argonne group leader.

“Our team not only found an antifreeze electrolyte whose charging performance does not decline at minus 4 degrees Fahrenheit, but we also discovered, at the atomic level, what makes it so effective,” said Zhengcheng ​“John” Zhang, a senior chemist and group leader in Argonne’s Chemical Sciences and Engineering division.

This low-temperature electrolyte shows promise of working for batteries in electric vehicles, as well as in energy storage for electric grids and consumer electronics like computers and phones.

An electric vehicle battery for all seasons, Joseph E. Harmon, Argonne National Labs