Optimization of the flexible supercapacitor

• Main Author: Ho, Kah Lin.
• Other Authors: Srinivasan Madhavi
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/15355
• Institution: Nanyang Technological University

Printed electronics is the key to the next generation of energy storage devices. Recently the emergence of printed electronic devices made using conventional printing processes can be seen. However, conventional charge storage devices are not fully compatible with these printed devices, which include electronic paper, wearable electronics and the like. In short, printed electronics requires printed power. Recent efforts have been focused on the development of supercapacitor that has high energy density for better performance and more demanding applications. While improving the performance of the supercapacitor, the fabrication efficiency is also another area to place high emphasis on. So far there is still no viable method reported and large-scale supercapacitor units for use in industrial applications are still undergoing further developments to explore cheaper components and manufacturing processes to enable their long-term economic viability. This project aim to (1) develop compatible energy storage devices and, (2) develop cost-effective manufacturing solutions for printed supercapacitor. Both Single-Wall (SWNT) and Multi-Wall (MWNT) Carbon Nanotube (materials for the device electrode) and Polyvinyl Alcohol/Phosphoric Acid (PVA/H3PO4) (materials for the device electrolyte) was used to improve the energy storage density of a supercapacitor on flexible substrate. Optimization of electrolyte coating and curing was conducted to enhance the performance of printed supercapacitors. Moreover, methods of lowering the Equivalent Series Resistance (ESR) of the device were also explored. Through this investigation, it is found out that it requires 7 days to obtain the lowest sheet resistivity of the electrode and to obtain a uniform layer of electrolyte coating cured at 60 oC. With the use of SWNT, device with lower internal resistance and higher specific capacitance compared to MWNT could be obtained at an optimum coating of electrolyte wet-thickness within 400 μm to 500 μm. A specific capacitance of 8.4mF/cm2 is obtained with these parameters. Aluminium foil laminated PET (Al-PET) substrate has also been used explored to minimize ESR.