Identification of carbon surface functionalities leading to pseudocapacitance

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The quest for alternative energy sources/storage systems has never been more vigorous than it is at present, and one strong contender for the energy storage market is the electrochemical capacitor (EC) (or "supercapacitor"). ECs are high power energy storage devices which can be used independently or can be coupled with low power/high energy systems (e.g. fuel cells and batteries) to satisfy modern day power requirements. Additionally, their long cycle life (> 1 000 000 cycles) and the fact that they are essentially maintenance free makes them ideal charge storage systems for intermittent energy sources (e.g. wind and solar power) and for remote applications. They have also been studied in vehicle applications (e.g. load-levelling and cold starting assistance) and as power line backup. This research project focuses on the identification of the different carbon surface functionalities (CSFs) (hydroxyl, carboxyl, carbonyl, pyrone, etc.) that exist on the surface of carbon electrodes used in aqueous EC systems. These CSFs can directly lead to more charge storage in the EC system (leading to a higher energy system). The identification of the CSFs will be undertaken by using some well established identification methods (Boehm's titration and Temperature Programmed Desorption), which while able to identify the CSFs, cannot provide information on whether these species can add to the charge-storage of the EC system. In this research, these methods will be coupled with powerful electrochemical and spectroscopic (Reflectance UV-Vis-NIR, IR and Raman) techniques to identify which of the CSFs is enhancing charge-storage. In addition, an Electrochemical Quartz Crystal Microbalance will be used (a very sensitive technique which allows for microgram changes in mass to be recorded) to help identify the reactions these CSF are undergoing to store the extra charge in the EC system. This research will greatly enhance the energy-storage abilities of EC systems that utilise carbon electrodes, and will thus make ECs a more viable commercial option for energy-storage.