The development of advanced materials for electrodes and electrolytes in supercapacitors

Date
2021-03-02
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Abstract

Supercapacitor is an important energy storage that can provide both high energy and power for modern electronic devices. In order to achieve high performance of supercapacitors, both electrode and electrolyte components are required to be improved. First, 3D structure of carbon nanotube (CNTs) electrodes are fabricated by using AMB1-bacteria to rearrange and link as uniformed CNTs network. This CNTs 3D electrode provides capacitance around 177 F/g at the scan rate of 1 A/g current density which is highly improved compared to pure unaligned CNTs electrodes. On the other hand, supercapacitor electrodes can also achieve high energy and power by utilizing the composite materials of graphene, MoS2 and polypyrole. At the optimal ratio of these composite materials, they will form the electrode structure with synergistic effects that allows electrolyte ions to charge at the surface superior than typical carbon electrodes. The optimal ratio composite electrode shows the specific capacitance approximately 387 F/g at the scan rate of 1 A/g current density. For electrolyte components, room temperature ionic liquids are selected to combined with additives such as polymers, organic solvents and ceramic fillers in order to obtain high ionic conductivity, thermal stability, mechanical stability and electrochemical stability performances for micro-supercapacitors. The optimal electrolyte is the combination of 1-Butyl-3-methylimidazolium bis(trifluorometylsulfonyl)imide or BMI-TFSI ionic liquid with BN-PVdF composite film (2:1:2 weight ratio) which shows the highest ionic conductivity at 1.98 mS/cm at room temperature with mechanical stable structure. Next, various active redox molecules are enhanced into the electrolyte to provide pseudo-capacitance for the supercapacitor devices. Hydroquinone and NaBrO3 shows the promising results of improving specific capacitance by approximately 50% compared to the control H2SO4 electrolyte. With these optimal electrode and electrolyte components, superior supercapacitors will be achieved. Lastly, some developments of carbon materials for other electronic applications are also included.

Description
Degree
Doctor of Philosophy
Type
Thesis
Keywords
Supercapacitor, energy storage
Citation

Kosolwattana, Suppanat. "The development of advanced materials for electrodes and electrolytes in supercapacitors." (2021) Diss., Rice University. https://hdl.handle.net/1911/110258.

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