WHAT DID THE 2011 EARLY CAREER AWARD ALLOW YOU TO DO?

Batteries are evaluated based on their performance, which includes properties such as stored energy and lifetime.

Many processes across a wide range of time and length scales are responsible for observed battery performance. Imaging these processes, especially on nanometer-length scales, is very challenging. But imaging could help identify bottlenecks for better performance and the origins of battery fade. It would help us redesign the battery from the bottom up.

The U.S. Department of Energy (DOE)’s Early Career Research Program Award (ECRP) enabled me to have a very detailed look into Li-ion batteries. My goal was to image and understand local ion transport on the level of individual grains and grain boundaries in classical Li-ion battery electrodes, in order to close the knowledge gap on these length scales.

To enhance the understanding of local ionic transport in battery materials, I used a novel approach. Instead of investigating electrochemical currents as in traditional battery research, I chose to detect electrochemical strains since they can be observed locally with microscopy which is not possible with current-based approaches. This allowed me to push the resolution limit down to tens of nanometers. I investigated the Li-ion motion in battery electrodes where I was able to map out properties such as activation energy barriers for Li-ion transport on the level of individual grains.

This approach allowed unprecedented insight into structure-property relationships. One of the biggest challenges was to identify electrochemical strain and put it into context of other, non-related, strain origins.

Beyond making progress in understanding ionic transport on the smallest length scales, the ECRP allowed me to learn how to develop a research program. This has been catalytic to my research career and also helped me excel in other areas of research.

ABOUT:

Nina Balke is a senior research scientist in the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory.

SUPPORTING THE DOE SC MISSION:

The Early Career Research Program provides financial support that is foundational to early career investigators, enabling them to define and direct independent research in areas important to DOE missions. The development of outstanding scientists and research leaders is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science.

For more information, please go to the Early Career Research Program.

THE 2011 PROJECT ABSTRACT:

Spatially Resolved Ionic Diffusion and Electrochemical Reactions in Solids: A Biased View at Lithium Ion Batteries

The overarching goal of this project is to understand the ionic diffusion and electrochemical reactions in Lithium‐ion batteries from the length scale of single microstructural elements to the macroscopic device level. A novel Electrochemical Strain Microscopy (ESM) probe with 100-fold better resolution than other probes will be used along with electrical and structural battery characterization techniques for macroscopic devices in combination with advanced theoretical modeling.

The research will shine light on the complex interplay of ionic and electronic transport in battery materials and their correlation with the structural material properties. This will result in new tools to characterize energy storage materials and enhance the fundamental understanding of the nanoscale processes that define a battery.

RESOURCES:

N. Balke, S. Kalnaus, N.J. Dudney, C. Daniel, S. Jesse, S.V. Kalinin, “Local Detection of Activation Energy for Ionic Transport in Lithium Cobalt Oxide.” Nano Lett. 12, 3399 (2012). [DOI: 10.1021/nl300219g]

N. Balke, S. Jesse, Y-H. Chu, S.V. Kalinin, “High-Frequency Electromechanical Imaging of Ferroelectrics in a Liquid Environment.” ACS Nano 6, 5559 (2012). [DOI: 10.1021/nn301489g]

N. Balke, P. Maksymovych, S. Jesse, I.I. Kravchenko, Q. Li, S.V. Kalinin. “Exploring Local Electrostatic Effects with Scanning Probe Microscopy: Implications for Piezoresponse Force Microscopy and Triboelectricity.” ACS Nano 8, 10229 (2014). [DOI: 10.1021/nn505176a]

DOE Explains… offers straightforward explanations of key words and concepts in fundamental science. It also describes how these concepts apply to the work that the Department of Energy’s Office of Science conducts as it helps the United States excel in research across the scientific spectrum. For more information on batteries and DOE’s research in this area, please go to “DOE Explains… Batteries.

 

Additional profiles of the 2011 Early Career Award recipients can be found at https://www.energy.gov/science/listings/early-career-program

The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit www.energy.gov/science.

Sandra Allen McLean is a Communications Specialist in the Office of Science, Office of Communications and Public Affairs [email protected].

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