Improving Lithium-ion Battery Power and Energy Densities Using Novel Cathode Architectures and Materials By

Lithium-ion batteries are commonly used as energy storage devices in a variety of applications. The cathode architectures and materials have a large influence on the performance of lithium-ion batteries, namely power and energy densities. Three-dimensional bicontinuous cathode structures should help improve the charge and discharge rate performances, while maintaining a high energy capacity. By controlling the pore architectures of the bicontinuous cathode structures, we hope to manipulate the power densities to our advantage. Here we demonstrate synthesis of anisotropic silica colloids with precise control over particle dimensions. Using external AC electric fields and casting techniques, the anisotropic colloids were made into useful templates for cathode fabrication. Nickel electrodeposition through the anisotropic colloidal templates, with subsequent template etching, produced nickel current collectors with rod-shaped pore architectures. Thin-films of lithiated manganese dioxide were deposited onto the nickel current collectors, and the cathodes were analyzed. New active materials in the three-dimensional bicontinuous cathodes should help to improve the overall energy density, without sacrificing structure-related power density. We demonstrate the ability to synthesize lithium manganese orthosilicate nanoparticles using a modified sol-gel route. Using this synthesis technique, a sol-gel dip-coating method on nickel foam is demonstrated and analyzed. These architectural and material fabrications demonstrated in this thesis provide new directions towards improving lithium-ion battery performance. iii ACKNOWLEDGEMENTS