H. Sun
University of South Dakota,
United States
Keywords: cathode, fluorine, lithium, polymer
Summary:
Fluorine plays an important role in modern functional materials ranging from consumer products to high tech defense applications. Of particular interests in the Center for Fluorinated Functional Materials, polyfluorinated and perfluorlkylated aromatics are studied for air-stable and flexible organic seminconductor applications. Perfluoroalkylated small molecules possess increased chemical- and photochemical-stabilities as well as the preferential formation of lamellar stacked packing motifs in organic semiconductor materials. Our recent work on fluoropolymers and fluoropolymer thin films reveals that with careful molecular design, significantly stable redox active polymers can be achieved by perfluoroalkylation of the polymer backbone. These redox active fluoropolymers possess broad applications in organic electronics, sensors, and batteries. In this presentation, synthesis, characterization, and electrochemical properties of perfluoalkylated polyaromatic hydrocarbons (PAHs) and redox active fluoropolymers will discussed. One interesting discovery from such work was that these redox active fluoropolymers were used as cathodic materials for battery applications after integrating a conductive polymer backbone and electron transfer catalysts onto the fluoropolymers. Our initial test shows that these redox active fluoropolymer cathodic materials can reach 1,000 mAh/g specific capacity with a working voltage of 2.1 V. The key innovation of this cathodic materials is that we successfully eliminate the use of binder and conductive materials for preparing the battery cathode, removing the non-redox-active materials (dead mass) from the cathode. A practical mass loading of mg/cm2 for this cathode material has been reached in our laboratory. Assemble of a prototype lithium battery cell is in progress.