In November, Assistant Professor Emily Ryan (ME, MSE) was awarded the 2017 Scialog Fellowship for Advanced Energy Storage, along with some of the nation’s finest researchers in the field.
With the Scialog initiative, the Research Corporation for Science Advancement (RCSA) – which awards these fellowships – aims to encourage collaborations between theorists and experimentalists. At the workshop held in November, they were able to do just that. “The idea behind the whole workshop was to bring together people who had never worked together to collaborate on a project, and bring in expertise from all sides,” says Ryan.
The Scialog workshop was focused on issues surrounding advanced battery technologies, exploring different research areas that need to be looked into, and ways in which the 65 fellowship recipients could collaborate. At the end of the workshop, researchers wrote grant proposals for seed funding from the RCSA for various groups of researchers. “I met people from all over the country, and I wrote a proposal with two of them to look at a specific issue. If they award us funding for it, we will have money for a year to try and accumulate data, after which we go back for another workshop with the same group, when there will be another opportunity to apply for follow on funding. The goal of the RCSA funding is to provide the opportunity to build collaborations and collect preliminary data so that we can then apply for for funding from the Department of Energy or the National Science Foundation,” explains Ryan, who worked on dendritic growth in batteries with researchers from Columbia University and California State University, Northridge.
Ryan’s research focuses on computational modeling for various energy related systems, wherein she studies multi-phase, multi-physics systems. The reactive transport inside batteries is one example, but she also looks at a variety of other systems for carbon capture at power plants, or cavitation in diesel fuel injectors.
In the battery field, she has been investigating dendrite growth in lithium batteries. Dendritic growths occur in both advanced lithium batteries and commercial lithium ion batteries (like in your cell phone) as you charge or discharge it. She explains, “It basically means that the surface – as the lithium is plated or used – does not grow uniformly, which causes these dendrite or tree-like structures to grow, which eventually leads to a loss in performance. There are other issues that lead to performance decreases as well, but dendritic growth is one of the major ones. You can see this is the performance drop in your cell phone over time, when you get a new phone it will last for a day or more, but after six months or a year, your cell phone might only last half a day before it needs to be charged.” Ryan adds that while dendrite growth leads to a performance issue, it could also cause problems with safety, because if these dendrites grow from one side of the cell to the other, they short-circuit. “When you hear about laptop battery fires, those kinds of things can happen due to dendrite growth.”
“It basically means that the surface – as the lithium is plated or used – does not grow uniformly, which causes these dendrite or tree-like structures to grow, which eventually leads to a loss in performance.”
Prof. Ryan has developed computational models to investigate the effects of mass transport near the interface on dendrite growth. Her proposal for the Scialog workshop aims to expand on that work and collaborate with experimentalists at Columbia University and theoretical chemists at California State University Northridge to further understand the driving forces of dendrite growth and to investigate methods to suppress and control the growth so to extend the life of batteries. The goal of the research is develop a multi-scale modeling framework that’s informed by the experiments to get a better paradigm to look at, understand it, and hopefully come up with solutions to dendrite growth problems.
While this research is focused on the safety and lifetime of these batteries, it’s also an energy efficiency issue, because the Li-ion batteries used today work on one chemistry, and based on that chemistry, there’s a limited amount of energy you can get out of them. Ryan says, “These lithium metal batteries, which is what we look at, are a slightly different chemistry, which actually have a practical energy density that’s an order of magnitude greater than Li-ion batteries. If we can get these systems to be commercial, then there is a possibility of your cellphone lasting a week instead of a day on a single charge, and there is also huge potential for use in electric cars.” She adds, “The best mileage one can get from electric cars today is roughly 200 miles, or 300 miles at the most. This performance, however, is limited to Tesla cars, which are unaffordable for a lot of people. With higher energy density batteries, there’s the possibility of getting much longer range in these cars, which means there’s potential for electric cars that can go up to 500 miles, just like a car that runs on gasoline.”