Chapters authored
Fiber Supercapacitors Based on Carbon Nanotube-PANI Composites
Flexible and wearable electronic devices are of a high academic and industrial interest. In order to power these devices, there is a need for compatible energy storage units that can exhibit similar mechanical flexibility. Fiber-based devices have thus become increasingly popular since their light-weight, and flexible structure can be easily integrated into textiles. Supercapacitors have garnered a lot of attention due to their excellent cycling durability, fast charge times and superior power density. The primary challenge, however, with electric double layer capacitors (EDLCs), which are part of the supercapacitor family, is that their energy densities are significantly lower compared to those of batteries. Pseudocapacitors, on the other hand, can be designed and created with large energy densities and other outstanding properties typical for supercapacitors. This chapter discusses the fabrication and testing of supercapacitors based on carbon nanotube-polyaniline (PANI) composite fibers. These flexible and light-weight devices are assembled using different electrolytes for comparison. The created in this work PANI-CNT composite devices attain an energy density of 6.16 Wh/kg at a power density of 630 W/kg and retained a capacitance of 88% over 1000 charge-discharge cycles.
Part of the book: Science, Technology and Advanced Application of Supercapacitors
Fabric-Integrated, Ionic Liquid-Based Supercapacitor as a Tunable and Flexible Power Source
With the introduction of flexible and wearable electronic technologies such as displays, antenna’s, etc., there has been an increased need for integrable, easily scalable, and safe electric power sources. Advances in flexible lithium-ion batteries have been recently reported, however they may still suffer from potential thermal runaways. In this chapter we review the progress in the topic of wearable energy storage devices. These devices have taken the form of both sheets and fibers entirely made of active material. We also discuss the advantages and drawbacks of each forms. Finally, we present our own work revealing a simplistic way to integrate working carbon electrode materials into suitable textile and to functionalize the obtained flexible structure with ionic liquid thus creating fabric supercapacitors. These devices can then be connected easily in series (9 V) or in parallel (high current), depending on the current or voltage requirements. The area of the electrodes can also be tuned to sustain higher capacitances. We report an energy density of 48 Wh/kg for a functional device at 3 V working window, which reveals no losses in energy density after 10,000 bending cycles.
Part of the book: Science, Technology and Advanced Application of Supercapacitors