Studies of the Vanadium Acetylacetonate Redox System and its Applications in Hybrid Supercapacitors
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Authors
Sciborski, Katie L.
Date
Type
thesis
Language
eng
Keyword
Vanadium , Supercapacitors , Energy Storage , Non-Aqueous
Alternative Title
Abstract
The pursuit of high-performing energy storage devices results in significant advancements in the field of electrochemical energy storage systems. This thesis investigates the development and performance of a non-aqueous redox supercapacitor utilizing vanadium acetylacetonate as the redox species and reduced graphene oxide as the electrode material. The research encompasses multiple chapters that explore critical aspects of the device's design and performance.
Electrode materials, solvents, supporting electrolytes, and separator materials are examined to develop a redox supercapacitor based on the non-aqueous vanadium system. Emphasis is placed on reduced graphene oxide and heteroatom-doped reduced graphene oxide as an electrode material.
The study demonstrates that the addition of a redox species to the electrolyte leads to a significant increase in capacitance compared to traditional supercapacitors. At high current densities, the redox supercapacitor exhibits a discharge capacitance of 637 F g-1 compared to the 31 F g-1 of a plain supercapacitor utilizing the same materials. At low current densities, the redox supercapacitor exhibits a discharge capacitance of 1032 F g-1 compared to the 144 F g-1 of the plain supercapacitor. The redox supercapacitor exhibits a discharge capacitance increase of 1955% and 617% at high and low current densities, respectively.
The study explores the performance of the device over cycling. The redox supercapacitor shows limitations over cycling due to unwanted ion crossover and degradation, notably at high current densities. At high current densities, the discharge capacitance decreases by 93% over 1000 cycles. At low current densities, the discharge capacitance of the redox supercapacitor decreases by 7% over 100 cycles.