In the Materials Virtual Lab (MAVRL), we aim to be a leader in bringing forth a data-driven future for materials design. Intersecting the disciplines of materials science and information science, our research combines novel materials informatics approaches with first principles calculations to probe nature’s laws and design novel materials.
Creating Rich Materials Data Infrastructure
Electronic structure calculation codes have reached a level of maturity that it is now possible to reliably automate and scale first principles calculations across any number of compounds.
In MAVRL, we develop the infrastructure to facilitate the creation and analytics of rich materials datasets. This infrastructure involves the development of flexible materials data representations for state-of-the-art database technologies, coupled with robust platforms for high-throughput computing. We founded the Python Materials Genomics (pymatgen) materials analysis package.
We are a key partner of the Materials Project, an open science initiative to make the data for all known inorganic compounds publicly available to all materials researchers to accelerate materials innovation. A recent web application developed by MAVRL is Crystalium, a database of the computed surface energies and Wulff shapes of all elemental crystals.
Developing Sophisticated Materials Informatics
Accuracy of DFT Large materials data sets call for new analytic approaches to find interesting structure-property relationships and to discover new materials or new applications for existing materials. We apply rigorous data mining techniques, such as cluster analysis, anomaly detection and association rule mining, to discover patterns in rich materials datasets. Our goal is to probe nature’s laws, improve on existing computational prediction methodologies and fine-tune well-established physical and chemical rules of thumb.
Designing Materials for Energy Applications
Effective materials design requires multi-property optimization. Computational materials screening therefore have to be customized to the application at hand, often with trade-offs between speed and accuracy. In the MAVRL, we combine first principles techniques with sophisticated thermodynamic analysis and robust IT infrastructure in materials design, with a heavy focus on materials for energy. Our energy research portfolio targets both energy storage and energy efficiency, with the aim of doing our part in addressing global climate change. The following are some of our current research interests:
Multi-electron rechargeable lithium-ion battery cathodes
The rechargeable lithium-ion battery is the dominant form of energy storage for the modern age. However, the energy densities, both gravimetric and volumetric, of today’s Li-ion batteries are still far below that necessary to displace gasoline combustion engines. For example, the capacities of the layered LiCoO2 cathodes, which have the highest theoretical energy density of current commercial cathodes, are capped at around 180 mAh/g , leading to corresponding calculated energy densities of around 1 kWh/kg and 3 kWh/l .
Current cathodes only transfer a maximum of one electron per transition metal, which limits achievable capacities. MAVRL is a proud member of the NorthEast Center for Chemical Energy Storage (NECCESS), an Energy Frontier Research Center funded by the US Department of Energy. Through NECCESS, we are developing multi-electron cathodes that reversibly cycle more than one electron per transition metal, in the hope of making batteries that are more energy dense than today’s lithium-ion batteries.
Alkali superionic conductor solid electrolytes
Today’s lithium-ion batteries also suffer from safety issues due to the flammable organic solvent electrolyte used. In MAVRL, we are working on developing a revolutionary all-solid-state battery architecture. In such batteries, a non-flammable solid electrolyte (an alkali superionic conductor) is used. Besides the obvious safety benefits, such an architecture can also potentially lead to higher system capacities by enabling higher voltages and allowing stacking.
In MAVRL, we go beyond the narrow focus on ionic conductivity typical in most other efforts. We view all-solid-state batteries as ultimately a multi-component optimization problem. We use first principles methods to study and design superionic conductors that are not only fast conducting, but also electrochemically stable and mechanically compatible with the electrodes. A holy grail is to enable the use of lithium metal, which is the highest energy density anode possible for lithium-ion battery technology.
Phosphors for solid-state lighting
Lighting is one of the largest consumers of energy today. An estimated 20% of total US electricity output is consumed in lighting our homes, offices and industries. Highly efficient light emitting diodes (LEDs) are one of the most promising technologies for next generation lighting. However, current LEDs still suffer from a fundamental tradeoff between luminous efficacy and color rendering.
In MAVRL, we use first principles calculations to understand and develop novel phosphor materials for LEDs. We seek to understand how the crystal and electronic structure affect the emission properties of phosphors, as well as their response to temperature and composition. In doing so, we aim to develop novel phosphor compositions that can significantly outperform today’s LED phosphors.
The Materials Virtual Lab gratefully acknowledges the generous funding provided by the US Department of Energy, the National Science Foundation, and the Office of Naval Research.