Jain, Ritika2021-12-202021-12-202021-08Jain_cornell_0058O_11247http://dissertations.umi.com/cornell:11247https://hdl.handle.net/1813/110415107 pagesLithium-ion batteries are gaining popularity with increasing use of electronic devices especially laptops, cameras, and phones. With more and more electric vehicles hitting the market, next generation batteries with several advantages like, high energy density, long cycle life, low self-discharging are required. Separators act as an electrical insulator between battery’s positive and negative electrode. They serve as an electrolyte reservoir and their structure plays an important role in battery’s cycle life, safety, energy density and capacity.In this study, Polyimide (PI) / Polysilsesquioxane (PSSQ) hybrid separators were successfully fabricated via a single step electrospinning process. They are thermally stable, and non-flammable separators that enable high capacity and high-rate Li-ion batteries to be safer. The novelty of this project lies in its fundamental improvement of electrospun fibers. It involves controlling and tailoring morphology of nanoscale fiber made from a polymer and ceramic blend to reduce non-uniformity in the fiber morphology, leading to improved performance at high charging and discharging rates, as compared to Celgard, a commercially used separator. Fiber morphology was controlled by the addition of various surfactants. Sodium dodecyl sulfate (SDS) modified hybrid separators showed the best battery performance when paired with high-rate capable Silicon-graphene anodes. This combination of anode and separator performed better than the pristine hybrid separators and Celgard at high-rate cycling. These high-rate capable separators show huge potential to enable fast charging for electric vehiclesendissertation or thesishttps://doi.org/10.7298/pyn4-zy20