A research team led by ORNL's Nina Balke, Stephen Jesse and Sergei Kalinin has developed a new type of scanning probe microscopy called electrochemical strain microscopy (ESM) to examine the movement of lithium ions through a battery's cathode material. The research, "Nanoscale mapping of ion diffusion in a lithium-ion battery cathode" (Balke et al.), is published in Nature Nanotechnology.
"We can provide a detailed picture of ionic motion in nanometer volumes, which exceeds state-of-the-art electrochemical techniques by six to seven orders of magnitude," Kalinin said. Researchers achieved the results by applying voltage with an ESM probe to the surface of the battery's layered cathode. By measuring the corresponding electrochemical strain, or volume change, the team was able to visualize how lithium ions flowed through the material. Conventional electrochemical techniques, which analyze electric current instead of strain, do not work on a nanoscale level because the electrochemical currents are too small to measure, Kalinin explained.
"These are the first measurements, to our knowledge, of lithium ion flow at this spatial resolution," Kalinin said.
Lithium-ion batteries, which power electronic devices from cell phones to electric cars, are valued for their low weight, high energy density and recharging ability. Researchers hope to extend the batteries' performance by lending engineers a finely tuned knowledge of battery components and dynamics.
"We want to understand - from a nanoscale perspective - what makes one battery work and one battery fail. This can be done by examining its functionality at the level of a single grain or an extended defect," Balke said.
The team's ESM imaging can display features such as individual grains, grain clusters and defects within the cathode material. The high-resolution mapping showed, for example, that the lithium ion flow can concentrate along grain boundaries, which could lead to cracking and battery failure. Researchers say these types of nanoscale phenomena need to be examined and correlated to overall battery functionality.
"Very small changes at the nanometer level could have a huge impact at the device level," Balke said. "Understanding the batteries at this length scale could help make suggestions for materials engineering."
Although the research focused on lithium-ion batteries, the team expects that its technique could be used to measure other electrochemical solid-state systems, including other battery types, fuel cells and similar electronic devices that use nanoscale ionic motion for information storage.
"We see this method as an example of the kinds of higher dimensional scanning probe techniques that we are developing at CNMS that enable us to see the inner workings of complex materials at the nanoscale," Jesse said. "Such capabilities are particularly relevant to the increasingly important area of energy research."
Balke, Jesse and Kalinin are research scientists at ORNL's Center for Nanophase Materials Science. The research team includes Nancy Dudney, Yoongu Kim and Leslie Adamczyk from ORNL's Materials Sciences and Technology Division. The key theoretical results in the work were obtained by Anna Morozovska and Eugene Eliseev at the National Academy of Science of Ukraine and Tony Chung and Edwin Garcia at Purdue University.
This research was supported as part of the Fluid Interface Reactions, Structures and Transport Center, an Energy Frontier Research Center funded by the Department of Energy, Office of Science.
Part of this work was supported by the Center for Nanophase Materials Sciences (CNMS) at ORNL. CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov. ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.
Morgan McCorkle | EurekAlert!
New material, manufacturing process use sun's heat for cheaper renewable electricity
22.10.2018 | Purdue University
3D-printed lithium-ion batteries
18.10.2018 | American Chemical Society
Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.
Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...
Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles
Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...
When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.
We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...
Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...
Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...
17.10.2018 | Event News
16.10.2018 | Event News
02.10.2018 | Event News
22.10.2018 | Ecology, The Environment and Conservation
22.10.2018 | Physics and Astronomy
22.10.2018 | Medical Engineering