Faster, more efficient energy storage could stem from holistic study of layered materials

August 25, 2020

A team led by the Department of Energy's Oak Ridge National Laboratory developed a novel, integrated approach to track energy-transporting ions within an ultra-thin material, which could unlock its energy storage potential leading toward faster charging, longer lasting devices.

Scientists have for a decade studied the energy-storing possibilities of an emerging class of two-dimensional materials - those constructed in layers that are only a few atoms thick - called MXenes, pronounced "max-eens."

The ORNL-led team integrated theoretical data from computational modeling of experimental data to pinpoint potential locations of a variety of charged ions in titanium carbide, the most studied MXene phase. Through this holistic approach, they could track and analyze the ions' motion and behavior from the single-atom to the device scale.

"By comparing all the methods we employed, we were able to form links between theory and different types of materials characterization, ranging from very simple to very complex over a wide range of length and time scales," said Nina Balke, ORNL co-author of the published study that was conducted within the Fluid Interface Reactions, Structures and Transport, or FIRST, Center. FIRST is a DOE-funded Energy Frontier Research Center located at ORNL.

"We pulled all those links together to understand how ion storage works in layered MXene electrodes," she added. The study's results allowed the team to predict the material's capacitance, or its ability to store energy. "And, in the end, after much discussion, we were able to unify all these techniques into one cohesive picture, which was really cool."

Layered materials can enhance energy stored and power delivered because the gaps between the layers allow charged particles, or ions, to move freely and quickly. However, ions can be difficult to detect and characterize, especially in a confined environment with multiple processes at play. A better understanding of these processes can advance the energy storage potential of lithium-ion batteries and supercapacitors.

As a FIRST center project, the team focused on the development of supercapacitors - devices that charge quickly for short-term, high-power energy needs. In contrast, lithium-ion batteries have a higher energy capacity and provide electrical power longer, but the rates of discharge, and therefore their power levels, are lower.

MXenes have the potential to bridge the benefits of these two concepts, Balke said, which is the overarching goal of fast-charging devices with greater, more efficient energy storage capacity. This would benefit a range of applications from electronics to electric vehicle batteries.

Using computational modeling, the team simulated the conditions of five different charged ions within the layers confined in an aqueous solution, or "water shell." The theoretical model is simple, but combined with experimental data, it created a baseline that provided evidence of where the ions within the MXene layers went and how they behaved in a complex environment.

"One surprising outcome was we could see, within the simulation limits, different behavior for the different ions," said ORNL theorist and co-author Paul Kent.

The team hopes their integrated approach can guide scientists toward future MXene studies. "What we developed is a joint model. If we have a little bit of data from an experiment using a certain MXene, and if we knew the capacitance for one ion, we can predict it for the other ones, which is something that we weren't able to do before," Kent said.

"Eventually, we'll be able to trace those behaviors to more real-world, observable changes in the material's properties," he added.
-end-
The paper titled, "Tracking ion intercalation into layered Ti3C2 MXene films across length scales," was co-authored by Qiang Gao, formerly of ORNL; Weiwei Sun of Vanderbilt University and formerly of ORNL; Arthur P. Baddorf, Nina Balke, Jingsong Huang, Stephen Jesse, Paul Kent and Wan-Yu Tsai of ORNL; Nadine Kabengi and Poorandokht Ilani-Kashkouli of Georgia State University; Alexander Tselev of the University of Aveiro, Portugal; Michael Naguib of Tulane University; and Yury Gogotsi of Drexel University.

The research was sponsored by DOE's Office of Science, though the FIRST EFRC, and used resources at the Center for Nanophase Materials Sciences at ORNL and the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory, both Office of Science user facilities.

UT-Battelle manages ORNL for the DOE Office of Science. The single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit https://www.energy.gov/science.

DOE/Oak Ridge National Laboratory

Related Behavior Articles from Brightsurf:

Variety in the migratory behavior of blackcaps
The birds have variable migration strategies.

Fishing for a theory of emergent behavior
Researchers at the University of Tsukuba quantified the collective action of small schools of fish using information theory.

How synaptic changes translate to behavior changes
Learning changes behavior by altering many connections between brain cells in a variety of ways all at the same time, according to a study of sea slugs recently published in JNeurosci.

I won't have what he's having: The brain and socially motivated behavior
Monkeys devalue rewards when they anticipate that another monkey will get them instead.

Unlocking animal behavior through motion
Using physics to study different types of animal motion, such as burrowing worms or flying flocks, can reveal how animals behave in different settings.

AI to help monitor behavior
Algorithms based on artificial intelligence do better at supporting educational and clinical decision-making, according to a new study.

Increasing opportunities for sustainable behavior
To mitigate climate change and safeguard ecosystems, we need to make drastic changes in our consumption and transport behaviors.

Predicting a protein's behavior from its appearance
Researchers at EPFL have developed a new way to predict a protein's interactions with other proteins and biomolecules, and its biochemical activity, merely by observing its surface.

Spirituality affects the behavior of mortgagers
According to Olga Miroshnichenko, a Sc.D in Economics, and a Professor at the Department of Economics and Finance, Tyumen State University, morals affect the thinking of mortgage payers and help them avoid past due payments.

Asking if behavior can be changed on climate crisis
One of the more complex problems facing social psychologists today is whether any intervention can move people to change their behavior about climate change and protecting the environment for the sake of future generations.

Read More: Behavior News and Behavior Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.