Structural and Functional Analysis of Spinels in Energy Storage Devices

As our world becomes increasingly mobile and wireless, our devices, vehicles, and homes demand more energy for longer amounts of time. With more research focusing on renewable energy generation, it is important to have high-powered and long lasting storage devices for optimum energy usage. The most recent electric storage technology introduced was the Lithium-ion battery in 1992 and since then, major efforts have been made to improve the most critical component: the cathode. Our research aims to study specific cathode materials called spinels at the nanoscale in order to fully understand what is necessary to optimize battery capabilities. Several spinels were synthesized with various elements in the crystal A site. The synthesis of the spinel cathode material was conducted via coprecipitation and then hydrothermal heating. The product was characterized by X-Ray Diffraction to confirm accurate crystallinity. The cathode was then made by creating a slurry of the spinel active material, carbon mixture, and a polymer binder. The slurry was coated onto Aluminum foil and dried in a vacuum oven. 1 cm diameter cathodes were punched from the coated foil and assembled into battery coin cells under inert gas in a glovebox, which were then discharged and recharged. Impedance testing was done to measure resistance within the batteries before and after each charge cycle. Our research also involved studying a new technique called Scanning Electrochemical Microscopy, which can be used for determining electrical conductivity of surface materials. SECM was found to be promising for measuring the conductivity of our various cathode materials while in electrolyte solution, which better simulates actual battery conditions. The results of this study found a promising cathode material for high-powered and long-lasting Lithium-ion battery applications. The methods used for synthesis proved efficient for making battery coin cells and the techniques used for characterization proved effective in forecasting battery performance.