Natale, GiovanniantonioRoberts, EdwardRaei, Mohammad Javad2023-10-032023-10-032023-09-22Raei, M. J. (2023). Design of electrochemically exfoliated graphene for supercapacitors (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/117325https://doi.org/10.11575/PRISM/42168Graphene, a 2D carbon-based material with exceptional characteristics, has proven its potential in various applications, branching into fields such as electronics, energy storage, sensors, and more. Various techniques have been developed to synthesize single and multi-layer graphene sheets. However, each method for utilizing graphene still presents a range of challenges, such as low yield, the use of toxic reagents, methods that are not scalable, time-consuming processes, and multi-step procedures. Among all these methods, electrochemical exfoliation is considered as a facile and environmentally friendly method which can prepare the doped and functionalized graphene with different elements, metals, metal oxides and polymers. In this work, we have modified the electrochemical exfoliation method and developed a novel procedure which can simultaneously produce doped and functionalized graphene with nitrogen, sulphur, phosphor, MnO2 and tannic acid. It was shown that the chemical structure of the graphene can easily be tuned for a specific application by utilizing different electrolytes. Additionally, the yield of this process has been increased by 78% by its combination with the liquid-phase exfoliation method, all without requiring any additional steps. Subsequently, as-synthesized composites have been investigated for energy storage in liquid and solid-state supercapacitors. We prepared the freestanding and flexible working electrodes by vacuum filtration of the graphene composites without the addition of any conductive additive and binder. It was shown that the pseudocapacitance behaviour of MnO2 can increase the capacitance of the graphene by 192% while showing 98.4% capacitance retention after 10,000 cycles. The obtained results suggest the great potential of the electrochemical exfoliation method for synthesizing graphene-based composites for application in energy storage devices.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.GrapheneElectrochemical ExfoliationSupercapacitorsEngineering--Chemicalmaster thesis