Design of novel electrolytes and electrodes for supercapacitors

Date

2023-12-26

Author

Keskin, Deniz

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Supercapacitors are emerging as promising electrical energy storage devices. They offer cyclic stability and high-power density when compared to batteries. Current studies focus on increasing electrochemical performance by introducing novel electrode and electrolyte materials and design strategies. Gel polymer electrolytes can be used for supercapacitor design due to their peerless properties, such as high ionic conductivity, environmental friendliness, and leakage-free nature. For novel electrolyte design, soy sauce as salt matrix and hydroxyethyl cellulose as polymer matrix are chosen. In this work, a zwitterionic and edible gel polymer electrolyte is presented with anti-freezing, anti-drying properties and high ionic conductivity of 1.3 × 10⁻¹ S·cm⁻¹. Electrodes are fabricated using activated carbon, glycerol, hydroxyethyl cellulose, and carbon black and fabricated edible supercapacitor yields in a specific capacitance of 3.75 F·g⁻¹ at a scan rate of 30 mV·s⁻¹. After 10,000 cycles, the capacitive retention is 86.5%. Two-dimensional materials can be utilized as electrode materials because they have large specific areas, high conductivity, tunable interlayer spacing, and adjustable active sites. One of the most studied two-dimensional materials for electrode design is 1T-molybdenum disulfide (1T-MoS₂). MoS₂'s layered morphology offers a high specific surface area and a short charge (ion/electron) transfer distance for electrochemical charge storage. For novel electrode design, 1T-MoS₂ and reduced graphene oxide nanocomposite electrodes are fabricated and used to fabricate micro supercapacitors. An areal capacitance of 32.5 mF·cm⁻² is obtained from the fabricated micro supercapacitor with H₂SO₄-PVA electrolyte. A capacitance retention of 91% is observed upon 3000 charge/discharge cycles.

Subject Keywords

Energy storage, Supercapacitor, Molybdenum oxide, Reduced graphene oxide, Micro-supercapacitor

URI

https://hdl.handle.net/11511/108206

Collections

Graduate School of Natural and Applied Sciences, Thesis