ETD Collection

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Author: search.filters.author.Tsoari, Thokozani

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    Supercapacitive performance of nickel(II) tetrapyrazinoporphyrazine modified titanium carbide nanosheets
    (2021) Tsoari, Thokozani
    Electrochemical capacitors are known to be energy storage devices with outstanding power delivery and uptake devices. Their prominent drawback is extremely low, and at best, modest energy density.. This research presents a new pathway into the exploration of two-dimensional materials as high energy electrode materials in symmetrical supercapacitor systems. We, for the first time in the reported history of MXenes and metallotetrapyrazinoporphyrazine complexes, report the combination of the lightest MXene, Ti2CTx, with nickel(II) tetrapyrazinoporphyrazine as active electrode material for supercapacitors in aqueous electrolyte to evaluate the resulting electrochemical performance. This novel composite was obtained by a simple intercalation of MXene via delamination by dissolved nickel(II) tetrapyrazinoporphyrazine. The rationale of this combination is to achieve synergized electrochemical performance through the intermix of unique respective properties from these materials: the metallic conductivity, capacitive, pseudocapacitive properties emanating from the surface physiochemistry of MXene nanosheets, and the redox catalytic activity of N4 metallo-macrocyclic complex. The electrochemical performance of alkaline, neutral, and acidic electrolyte systems is assessed by employing cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The highest obtained specific gravimetric capacitance is 109.5 F/g the nickel(II) tetrapyrazinoporphyrazine modified MXene. The broadest full cell operating window was 0.8 V for near-neutral based electrolyte. Full cells in basic media exhibited the most inferior performance in terms of stability as drastic capacitance fall off is observed after 2000 cycles