Supercapacitors are devices to use in situations where high charge/discharge rates and long cycle life are important. In particular, electrochemical supercapacitors (ESC) are devices that bridge the gap between batteries (high energy, low power) and capacitors (high power, low energy).1 Commercially available ESCs store less charge than batteries as they are limited by storing charge electrostatically at the electrode-electrolyte interface. To increase the charge storage capability while minimizing the amount of active material needed, we focus on using electroactive polymers as active materials in ESCs. They are capable of storing charge both at the electrochemical double layer and in the film itself through faradaic charge transfer (pseudocapacitance). Our current efforts are focused on optimizing soluble co-polymers containing 3,4-propylenedioxythiophene (ProDOT) and 3,4-ethylenedioxythiophene (EDOT) units that can be coated onto an electrode with a variety of roll-to-roll compatible methods. ProDOT:EDOT2 can be functionalized with different side-chains to tune solubility and electrolyte compatibility. This polymer is synthesized with tetraester side-chains (A in Fig. 1) that make it organic soluble and compatible for devices with propylene carbonate-based (PC) electrolytes. If this polymer is hydrolyzed to a polyelectrolyte form it becomes water-soluble (B in Fig. 1). This is especially attractive for safer processing conditions and reducing environmental impact.2 Treating the films with an acid renders the films solvent resistant (C in Fig. 1), allowing for devices to be made using both organic and aqueous electrolytes. We show that by optimizing side chain and electrolyte, we can fabricate solution processable ESCs with subsecond discharge rates while maintaining stable capacitance. 1. Österholm, A.M.; Shen, D. E. et al. ACS Appl. Mater. Interfaces. 2013, 5, 13432. 2. Ponder, J. F.; Österholm, A.M.; Reynolds, J. R. submitted to Adv. Mater. 10/2015

Solution processable dioxythiophene polymers as active materials in aqueous and organic supercapacitors

251st National Meeting (2016)

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