thesisElectrochemical capacitors, or "supercapacitors", are an electrochemical energy storage technology with high-power density and long cycle life compared to batteries. Supercapacitors have many promising applications in electric vehicles, renewable energy storage, consumer electronics, environmental sensors, biomedical implants, and grid energy storage. Conductive polymers are a material of interest for supercapacitor energy storage because of their ability to store energy by both electric double layer capacitance and "pseudocapacitance" (surface reduction-oxidation reactions). Polypyrrole is a widely used conductive polymer for supercapacitor electrodes, as well as in lithium-ion batteries. For applications in environmental sensors, transient electronics, and implantable devices, it is necessary to find supercapacitor electrode materials that are easily biodegradable. A variation of polypyrrole exhibiting methyl carboxylate side chains, which we call "MPC polymer," is presented in this thesis as a dissolvable supercapacitor electrode. It is, to the best of our knowledge, introduced for the first time as a dissolvable electrochemical energy storage material. The supercapacitor characteristics of MPC polymer are characterized for planar electrodes as well as a nanocellulose-based composite. The MPC polymer is found to have capacitance, cycle life, and impedance characteristics comparable to state-of-the-art polypyrrole
