“You might get seven or eight hours out of your iPhone on one charge, maybe a day,” says Reza Shahbazian-Yassar, an associate professor of mechanical engineering at Michigan Technological University. “This is not enough for many of us. A fully electric car, like the Nissan Leaf, can go up to 100 miles on a single charge. To appeal to a mass market, it should be about 300 miles. We want to increase the power of these systems.”
Michigan Tech's Reza Shahbazian-Yassar has developed a device that allows scientists to watch lithium ions at work inside a battery, opening the door to better designs and materials. Above, (a), the nanobattery setup inside the aberration corrected scanning transmission electron microscope. Below, (b), atomic resolution imaging of the front line of lithium ions entering a tin oxide nanowire. The atomic resolution images show the parallel lithium-ion channels and the formation of dislocations at the tip of the channels.
To wring more power out of lithium ion batteries, scientists are experimenting with different materials and designs. However, the important action in a battery occurs at the atomic level, and it’s been virtually impossible to find out exactly what’s happening at such a scale. Now, Yassar has developed a device that allows researchers to eavesdrop on individual lithium ions—and potentially develop the next generation of batteries.
Batteries are pretty simple. They have three major components: an anode, a cathode and electrolyte between the two. In lithium batteries, lithium ions travel back and forth between the anode and cathode as the battery discharges and is charged up again. The anodes of lithium-ion batteries are usually made of graphite, but scientists are testing other materials to see if they can last longer.
“As soon as lithium moves into an electrode, it stresses the material, eventually resulting in failure,” said Yassar. “That’s why many of these materials may be able to hold lots of lithium, but they end up breaking down quickly.
“If we were able to observe these changes in the host electrode, particularly at the very early stage of charging, we could come up with strategies to fix that problem.”
Ten years ago, observing light elements such as lithium or hydrogen at the atomic level would have been out of the question. Now, however, it’s possible to see light atoms with an aberration corrected scanning transmission electron microscope (AC-STEM). Yassar’s team was able to use one courtesy of the University of Illinois at Chicago, where he is a visiting associate professor.
To determine how the host electrode changes as lithium ions enter it, the team built a nano-battery within the AC-STEM microscope using a promising new electrode material, tin oxide, or SnO2. Then, they watched it charge.
“We wanted to monitor the changes in the tin oxide at the very frontier of lithium-ion movement within the SnO2 electrode, and we did,” Yassar said. “We were able to observe how the individual lithium ions enter the electrode.”
The lithium ions moved along specific channels as they flowed into the tin oxide crystals instead of randomly walking into the host atoms. Based on that data, the researchers were able to calculate the strain the ions were placing on the electrodes.
The discovery has prompted inquiries from industries and national labs interested in using his atomic-resolution capability in their own battery-development work.
“It’s very exciting,” Yassar said. “There are so many options for electrodes, and now we have this new tool that can tell us exactly what’s happening with them. Before, we couldn’t see what was going on; we were just guessing.”
The work was supported by the National Science Foundation and the American Chemical Society Petroleum Research Fund.
An article on the research, “Atomic Scale Observation of Lithiation Reaction Front in Nanoscale SnO2 Materials,” was published online June 3 in ACS Nano. In addition to Yassar, the coauthors are mechanical engineering graduate student Hasti Asayesh-Ardakani and research associate Anmin Nie of Michigan Tech; Li-Yong Gan, Yingchun Cheng and Udo Schwingeschlogl of King Abdullah University of Science and Technology, Saudi Arabia; Qianquin Li, Cezhou Dong and Tao Wang of Zhejiang University, China; and Farzad Mashayek and Robert Klie of the University of Illinois at Chicago.
Marcia Goodrich | Newswise
The role of Sodium for the Enhancement of Solar Cells
17.07.2018 | Max-Planck-Institut für Eisenforschung GmbH
Behavior-influencing policies are critical for mass market success of low carbon vehicles
17.07.2018 | International Institute for Applied Systems Analysis (IIASA)
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering