Lowering the cost and improving the performance of batteries for plug-in electric vehicles (PEVs) requires improving every part of the battery, from underlying chemistry to packaging. To reach the EV Everywhere Grand Challenge goal of making plug-in electric vehicles as affordable and practical as a 2012 baseline conventional vehicle by 2022, the Vehicle Technologies Office supports work to research the fundamental chemistries and materials associated with lithium-ion (Li-ion) and beyond Li-ion batteries. To learn how batteries are used in plug-in electric vehicles, visit the Alternative Fuels Data Center's page on batteries.
The Vehicle Technologies Office carries out exploratory battery materials research as part of its Batteries for Advanced Transportation Technologies (BATT) Program, led by a team of national laboratories and universities.
By starting with the fundamental components, researchers can improve current technologies and develop new ones. For existing battery chemistries, they study why and how current battery materials fail using advanced modeling and characterization techniques. Then, based on those results, they propose and test various solutions to alleviate these problems. In particular, the research focuses on improving battery's energy density while ensuring they operate safely, have a long life and a low cost.
Researchers also investigate new and promising materials for future battery chemistries:
- Advanced cell chemistries that promise higher energy density than current ones
- Li-ion anodes that are higher capacity than traditional carbon based electrodes
- New electrolytes that are more stable than current ones
- New cathode materials with high voltage and capacity
- Inactive components in the battery that can perform multiple roles
This work helps researchers develop next-generation Li-ion batteries, as well as "beyond Li-ion" technologies such as lithium-sulfur and lithium-air chemistries. Researchers are addressing issues that prevent these technologies from reaching commercialization, including poor cycle life, low power, low efficiencies, and issues with safety. They are investigating a number of potential solutions, including:
- Improving electrolyte / separator combinations so that they result in less dendrite growth when using Li metal anodes (dendrite growth can lead to shorts in the battery)
- Developing advanced material coatings
- Developing new ceramic, polymer, and hybrid structures with high ionic conductivity, low electronic impedance, and high structural stability
Researchers also work to develop advanced diagnostics and analytical methods that can improve the ability to do research. For example, Brookhaven National Laboratory is using X-rays at the National Synchrotron Light Source (NSLS) to study how the structure of Li-ion batteries' cathode materials change during lithium extraction, which is critical for understanding and designing better materials. This research should help scientists better understand how battery materials change as they test or combine them with other types of materials.
As part of this work, Lawrence Berkeley National Laboratory (LBNL) and the Massachusetts Institute of Technology (MIT) run the Materials Project, which allows researchers to use a search engine interface to sort more than 20,000 types of materials. It includes a Lithium Battery Explorer, which allows researchers to search the database for materials that satisfy critical criteria for lithium batteries.