More Powerful, Longer-Lasting Lithium Batteries on the Horizon after Sandia-Developed Materials Breakthrough

    LIVERMORE, Calif.--March 6, 2003--Researchers at the Department of Energy's Sandia National Laboratories in Livermore, Calif., have developed a new class of composite anode materials composed of silicon and graphite that may double the energy storage capacities currently possessed by graphite anodes, potentially leading to rechargeable lithium-ion batteries with more power, longer life, and smaller sizes.
    "Manufacturers of electric automobiles, laptop computers, cell phones, power tools, and other hybrid microsystems will likely all benefit from this kind of technology," said Scott Vaupen of Sandia/California's Business Development Department. Sandia, Vaupen said, is actively seeking collaborators to further develop the technology for eventual licensing and commercialization.
    The marriage of silicon and graphite may improve the specific capabilities of commercial graphite anode materials up to 400 percent, said Jim Wang, an Analytical Materials Science manager at Sandia.
    "Currently, no device exists that is altogether small, robust, long lasting, and high-powered enough to meet the requirements of hybrid microsystems," says Wang. "Electronics designers are forced to use low power-consumption components and designs that are limited in their longevity. Our newly discovered anode materials can improve the performance of microsystems by allowing for more powerful, sophisticated electronic components and by reducing the size and weight of the overall system."
    Wang said researchers have, for years, been vexed by the capacity limits associated with traditional lithium battery anodes. Sandia turned to silicon, which offers more than 10 times the lithium capacity potential of graphite, but is hampered itself by a rapid capacity loss during the battery cycling phase. When small particles of silicon are combined within a graphite matrix, however, the large capacities are retained.
    "The promising aspects of these materials are the large capacities, the capacity retention during cycling compared to other high-capacity materials, and the ability to control its performance by changing the composite composition and microstructure," Wang said.
    Karl Gross, one of the principal investigators on the team, said the silicon/graphite composites can be produced via a simple milling process. The production technique is common within the battery industry, and the raw materials needed to produce the electrode material have proven to be inexpensive and abundant, Gross said.
    The work was sponsored by Sandia's Laboratory Directed Research and Development (LDRD) Office, in collaboration with David Ingersoll of Sandia's Lithium Battery R&D Department in New Mexico.
    Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration. Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
    For information regarding possible collaboration towards commercialization or licensing opportunities, contact Scott Vaupen at 925/294-2322, sbvaupe@sandia.gov.