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David Lacina and Weimin Zhou prepare a LabVIEW program to measure the hydrogen uptake and release from a complex hydride in solution.
One of the more promising near-term ways of reducing our dependence on foreign oil and our energy-related emissions is the development of economical, plug-in hybrid electric vehicles. However, in order to meet the driving range and performance expectations of most consumers, these types of high-power mobile devices will require better, cheaper lithium batteries with new electrodes composed of inexpensive materials that can accommodate more lithium without compromising the system size, weight or cycle life.
Two Brookhaven programs have been researching materials for lithium batteries for nearly a decade. These two programs, Applied Battery Research and Batteries for Advanced Transportation Technology, are both funded by the DOE’s Office of Energy Efficiency and Renewable Energy. The programs aim to develop new batteries with longer cycling and calendar life, higher capacity, low cost and improved safety characteristics. Research accomplishments include development of new electrolytes and electrolyte additives for lithium batteries, and development of numerous x-ray absorption and diffraction technologies for battery and fuel cell material studies using the unique DOE -funded facilities located at Brookhaven, such as the beam lines at the NSLS.
Brookhaven scientists are preparing new nanoscale electrode materials capable of higher lithium capacities and rapid cycling rates. Alternative high capacity anodes (the negative electrode) have the potential to double or triple the cell capacity, but these materials are plagued by large volume changes and phase transitions that limit the cycle life. In general, a number of challenges arise with the structural changes, like volume expansion and phase changes, that accompany an increase in lithium density. These changes tend to damage the electrode during cycling making them unsuitable for rechargeable lithium batteries. Electrodes prepared from nanocrystalline powders and nanofilms may be able to sustain large volume changes without particle breakup. These electrodes exhibit improved cycling characteristics as a result of their nanoscale dimensions, which means the battery can be cycled more often without losing capacity.
In addition, the nanoscale particle dimensions also promote fast cycling rates, which means higher power capabilities and less time needed to recharge the battery. The new nano synthesis and characterization facilities at the CFN will give Brookhaven a unique opportunity to explore atomic- and molecular-level processes.
On the other side of the battery, the researchers are looking at
improving the positive electrode (cathode) by developing materials that
can “host” more lithium. In a typical cathode, the negative charge from
is donated to a metal ion in a process called reduction. Normally, there is one metal atom for every lithium atom that is cycled in the battery. Since the metal atoms are heavy, this ultimately limits the capacity of the host material. The Brookhaven team is developing new cathode materials with metal ions that can accommodate two or more electrons to significantly increase the electrode capacity and ultimately reduce the size and weight of the battery.
Brookhaven scientists have embarked on a number of new initiatives designed to move forward their fuel cell and battery programs. These include internally funded studies and proposals on the frontier of our existing science. A new Laboratory Directed Research and Development project on energy will focus on nanoscale electrodes for lithium batteries. This project includes efforts in materials synthesis, electrochemistry, and microscopy. The goal is to understand how electrode morphology and microstructure affect and are affected by lithium charging and repeated cycling using high-resolution electron microscopy and microanalysis.
A proposal for an Energy Frontier Research Center on hydrogen storage materials, titled “Interfacial Thermodynamics at the Nanoscale,” has been submitted. This effort is being led by the California Institute of Technology and includes partners from Carnegie Institution, University of California-Irvine, and HRL Laboratories. A number of other national and international collaborations are already in place for the hydrogen storage programs. A second proposal for an Energy Frontier Research Center on lithium batteries, titled Northeastern Chemical Energy Storage Center, was also submitted. This effort is being led by Stony Brook University and includes partners from Rutgers, Massachusetts Institute of Technology, Binghamton University, Lawrence Berkeley Laboratory, Argonne National Laboratory, and the Universities of Michigan and Florida.
The development of improved hydrogen storage systems will usher in a new type of fuel-cell car that closely resembles the vehicles on the road today with one important difference: no tailpipe emissions. Similarly, if batteries can be made to power electric hybrid plug-in vehicles for a 40-mile range, there will be a significant increase in the demand for these vehicles. Fundamental and applied research efforts in energy storage and alternative energy carriers like these at Brookhaven are crucial if the nation is to meet the challenges of our energy future. Success will mean elimination of the need for petroleum for most U.S. commuters and significant reduction of our energy-related emissions and dependence on foreign oil.
Last Modified: November 6, 2009