Leading the charge in rechargeable batteries
Rechargeable batteries are vital to modern mobility, whether in cell phones, laptops or electric vehicles (EVs). In addition, rechargeable lithium-ion batteries are a key component of a worldwide renewable energy infrastructure — enabling the storage of solar and eolic (wind) energy to move away from central-grid energy technologies and our dependence on fossil fuels.
Materials engineers at Purdue are working to make lithium-ion batteries even better. We’re researching materials-related innovations that will address these batteries’ current inefficiencies and help us realize the full potential of this storage technology.
A rechargeable battery is an electrochemical device that stores, and then provides, energy to modern electronic devices. It is rechargeable in that we can return the electrical energy to the battery to (ideally) restore the amount of energy it had before we started using it.
Batteries face three main challenges — charging time, long-term life, and degradation and safety. Charging times are especially important for EVs. Long-term battery life is an environmental necessity, and a lack of it poses an economic barrier to EV adoption. Batteries currently last two to five years — OK for cell phones, but an economic impediment when you consider the cost to replace the battery of your EV. To prevent degradation and enhance safety, the underlying stability of the materials is crucial, and we are just beginning to understand how to connect the microscopic physics at that level to the macroscopic level.
At Purdue, we have created theories and methods to understand the physics of performance and degradation at the granular level — what happens inside a single particle of active material in the 50 nanometer-to-1 micrometer range. We are leveraging our understanding of materials and advanced computation into a data-driven infrastructure with machine learning algorithms to assess the impact of tens of thousands of simulations within minutes.
At the most fundamental level, we have discovered how differing crystal structures, in combination with defects at the atomic and microstructural level, affect the performance and degradation of the battery cell. In battery cathode particles, we have highlighted how internal particle-to-particle contacts — the grain boundaries — can be engineered to maximize efficiency. In the anode, we pioneered the development of a basic understanding of “dendrite” growth, which reduces battery efficiency and performance. (Dendrites are branching, treelike outgrowths; in this case, they are the local accumulation of lithium at the surface of anode particles).
At the microstructure level (1 to 100 micrometers), we have contributed to connecting the physics of a single particle to multiple particles and developed methodologies that enable porous electrode microstructures to be engineered to maximize their performance. These investigations typically take two years to develop, compute and analyze, but with the help of collaborators, we have formulated novel numerical and theoretical methods to reduce this time to milliseconds. We’ve also developed practical industrial formulas to predict the long-term degradation of batteries as they are used on the road, as well as numerical, physics-based models to automate the prediction of battery performance in these conditions.
Our team of materials engineers is supported by the Toyota Research Institute (TRI), the National Science Foundation (NSF) and the Office of Naval Research (ONR). We’re also working with researchers from Darmstadt Technical University, Stanford and MIT.
The design and development of advanced rechargeable batteries requires the integration of advanced chemistries, processing techniques, modeling and simulation, data analytics, and AI. Our efforts in this arena have compressed research, design, simulation and development cycles by literally years — providing the basis for technology innovations that balance performance, long-term life, and safety while minimizing cost and, most importantly, environmental impact.
R. Edwin García, PhD
Professor, School of Materials Engineering
College of Engineering
Purdue University
