Browsing by Author "Kosolwattana, Suppanat"
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Item Bacteria as Bio-Template for 3D Carbon Nanotube Architectures(Springer Nature, 2017) Ozden, Sehmus; Macwan, Isaac G.; Owuor, Peter S.; Kosolwattana, Suppanat; Autreto, Pedro A.S.; Silwal, Sushila; Vajtai, Robert; Tiwary, Chandra S.; Mohite, Aditya D.; Patra, Prabir K.; Ajayan, Pulickel M.It is one of the most important needs to develop renewable, scalable and multifunctional methods for the fabrication of 3D carbon architectures. Even though a lot of methods have been developed to create porous and mechanically stable 3D scaffolds, the fabrication and control over the synthesis of such architectures still remain a challenge. Here, we used Magnetospirillum magneticum (AMB-1) bacteria as a bio-template to fabricate light-weight 3D solid structure of carbon nanotubes (CNTs) with interconnected porosity. The resulting porous scaffold showed good mechanical stability and large surface area because of the excellent pore interconnection and high porosity. Steered molecular dynamics simulations were used to quantify the interactions between nanotubes and AMB-1 via the cell surface protein MSP-1 and flagellin. The 3D CNTs-AMB1 nanocomposite scaffold is further demonstrated as a potential substrate for electrodes in supercapacitor applications.Item The development of advanced materials for electrodes and electrolytes in supercapacitors(2021-03-02) Kosolwattana, Suppanat; Ajayan, PulickelSupercapacitor 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.