| The depletion of fossil fuels and tons of CO2 released from its combustion have stimulated development of environment-friendly plug-in hybrid and electrical vehicles (EVs), and renewable energy (e.g., wind, solar). Both EVs and renewable energy applications highly depend on the advanced energy storage and conversion techniques. Lithium-ion batteries are considered as the most promising choice because of their light weight, long life span, and high energy density.;However, the current commercial anode material---graphite only has a theoretical capacity of 372 mAh g-1, which heavily hinders the further development of lithium ion batteries. Its relatively slow kinetics at high powers also fails to satisfy the high-power requirement of EVs. Therefore, it is urgent to seek new materials with excellent structural stability, and that show high power density and stable cyclic performance. To address those challenges, two well-known guidelines (e.g. reducing particle size and coating carbon Iayer) are applied in designing desired material in this proposal. In addition, a novel synthetic method --- instant gelation, is developed to prepare porous materials with high surface area for better contact of electrode materials and electrolyte. The micro- or mesopores inside the materials help reduce the resistance for lithium ions transport. The materials synthesized include already widely studied metal oxides, and fast rising metal sulfides.;Epitaxial metal oxide nanocomposite films, possessing interesting multifunctionality, have been applied in wide range of device applications. However, films are usually produced by high-vacuum equipment like pulse laser deposition, molecular beam epitaxy, and chemical vapor deposition. As an alternative, chemical solution approaches are not only cost-effective but also offer advantages over large surface coating, good control of stoichiometry or possible dopants. Therefore, we first reviewed the chemistry behind several main solution approaches including sol-gel, metal organic decomposition, dictate, polymer-assisted deposition, hydrothermal, and presented seminal works reported so far to demonstrate the advantages and disadvantages of different routes. Then, two epitaxial nanocomposite film systems are prepared via the newly developed, most promising polymer-assisted deposition method. The films' quality and magnetoresistance are studied and compared with that of films prepared by different methods in literature. |
