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Kinetically Controlled Catalytic Nanofabrication of Semiconductor and Ferroelectric Thin Films and Nanoparticles: Unique Advantages for Next-Generation Li-ion Batteries

Seminar Group: 


Professor Daniel E. Morse


Center for Energy Efficient Materials,
University of California, Santa Barbara


Friday, January 13, 2012 - 4:00pm


ESB 1001

Biological systems fabricate high-performance materials at low temperatures and near-neutral pH with a precision of nanostructural control that exceeds the capabilities of present human engineering. We discovered the mechanism governing nanofabrication of silica in a marine sponge, and translated this mechanism to a generic new, "biologically inspired" low-temperature method for the kinetically controlled catalytic synthesis of a wide range of nanostructured semiconductor thin films and nanoparticles without organic templates. Employing vapor-diffusion of catalysts at low temperature, this method preserves the intermetallic organization of bimetallic precursors that are thus incorporated into crystalline solids without phase segregation. Results include the first low-temperature synthesis of 6 nm barium titanate nanoparticles with low polydispersity, good electronic properties and no organic contaminants. A wide range of other materials made by this lowtemperature process offers unique combinations of nanostructures and properties not readily attainable by conventional high-temperature processes. These exhibit potential advantages now under investigation for improved magnetic ordering of layered metal hydroxides, improved high power-density and fireproof batteries, and various ferroelectric, infrared, piezoelectric and optoelectronic applications.

Especially promising applications have been discovered for high-performance Li ion and Li batteries. Anodes made by this method consist of tin or silicon nanoparticles uniformly dispersed by synthesis in situ within the pores of highly compliant and conductive microparticulate graphite or bulk multiwall carbon nanotubes; these composites exhibit electrochemical capacity and power density significantly greater than present commercial materials with exceptionally stable cyclability. Catalytically produced nanocomposite spinel-CNT cathodes exhibit high voltage, high capacity and superior cyclability. Thin films of doped barium strontium titanate made by kinetically controlled catalytic nanofabrication offer the prospect of safer batteries via an internal protectant against thermal runaway. Commercially affordable scalability of these materials is being developed, with continuous production of the nanocrystalline doped barium strontium titanate recently accomplished