The Importance of Nanotechnology in Developing Better Energy Storage Materials for Automotive Transport 2008-01-0689

Traditional electrode materials for lithium-ion storage cells are typically crystalline layered structures such as metal oxides, and graphitic carbons. These materials power billions of portable electronic devices in today's society. However, large-scale, high-capacity storage devices capable of powering hybrid electric vehicles (HEV″s) or their plug-in versions (PHEV's) have much more demanding requirements with respect to safety, cost, and the power they must deliver. Recently, nanostructured solid state materials, which are comprised of two more compositional or structural phases, have been found to show exciting possibilities to meet these criteria. Such concepts are exploited where the intimate mix of components at the nanoscale enhances reversibility, and capacity - essential for new cathode materials that function on the basis of intergrowth structures; and poorly conductive materials where limitations to electron or ion transport must be overcome by judicious design of nanostructured composites. Moreover, by definition, the interphase between the electrode and electrolyte forms a complex nanostructure that must be tailored to optimize transport properties. The research trends and future prospects in these areas are reviewed and discussed.