NOVEL NANOSTRUCTURED MATERIALS FOR ENERGY PRODUCTION AND STORAGE SYSTEMS

The increasing role of technology in our lives necessitates the development of advanced energy storage technologies, ranging from portable electronic devices to hybrid electric vehicles. Considered the most advanced of the available rechargeable technologies, lithium ion batteries rely on solid state intercalation compounds that are able to reversibly intercalate lithium within both electrode structures. Both cell voltage and capacity are governed by the materials chemistry. The capability to improve that chemistry resides in a better understanding of the processes that occur in the bulk in addition to the development of some new materials based on nanostructured concepts. Traditional electrode materials for lithium-ion storage cells are based on materials which have both mixed electron and ion transport (for Li+). They are typically crystalline layered structures such as metal oxides that have high redox potentials, and act as positive electrodes; and graphitic carbons capable of reversible uptake of Li at low potentials which act as negative electrodes. Recently, however, nanostructured solid state materials, which are comprised of two or more compositional or structural phases, have been considered. This new area has been particularly exploited in the area of negative electrode design, where the intimate mix of components at the nanoscale permits and enhances Li reversibility. It also include cathode materials where materials that function on the basis of intergrowth structures (internal composites) have been found to be beneficial; and insulating materials where the limitations to electron transport must be overcome by judicious design of nanostructured composites. The present communication is a brief overview of some developments based on our work that highlights key points in anode and cathode design based on this theme. The research trends and future prospects are also discussed