Development of Carbon Nanotubes-based Supercapacitors and A Discharge Model
Open Access
- Author:
- Ma, Danhao
- Area of Honors:
- Energy Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Ramakrishnan Rajagopalan, Thesis Supervisor
Dr. Sarma V Pisupati, Thesis Honors Advisor - Keywords:
- carbon nanotubes
supercapacitors
discharge model
electrochemistry
high power density - Abstract:
- A unique carbon nanotube-based electrode processing technique, named post-synthesis self-assembly technique, was developed in this thesis. The prepared electrodes obtained superior properties including flexibility, binder-free, light-weight, and excellent pore structures for aqueous supercapacitors. The supercapacitors were demonstrated to be charged/discharged at high current load of 50A/g for over 10,000 cycles without any fading in the capacitance. In this work, a power density of 1040 kW/kg was obtained in the supercapacitors using carbon nanotubes-based electrodes. That was due to the unique porous electrode structures and low internal electrical resistance. The specific capacitance was enhanced by decorating the pseudocapacitive materials on the carbon nanotubes-based electrodes. By doing so the supercapacitor maintained the high power performance and doubled the energy performance. The supercapacitors showed promising applications in microelectronics, and flexible energy storage devices. A physicochemical mathematical model was developed to understand the discharge characterization of supercapacitors including electric double layer formation, charge- and mass-transfer limitations, and resistive contact at the electrode/current collector interfaces. The model helped design desired properties and minimize unfavorable reactions in the supercapacitors during the charge/discharge cycles. The model also served as a tool to diagnose the issues on the discharge behavior, and to improve the supercapacitor system.