Facile and High-Throughput Fabrication of Carbon Nanotube Carpet-PDMS Structures toward Flexible Supercapacitors

R. Zhang, J. Ding, E.H. Yang
Stevens Institute of Technology,
United States

Keywords: flexible supercapacitors, VACNTs, PDMS, fabrication

Summary:

Flexible electronics have a wide range of applications in wearable and multifunctional electronics [1], including flexible displays, curved smart phones, electronic skins, and implantable medical devices. Consequently technologies for flexible energy storage will have to be developed for such flexible electronic devices [2]. The fabrication process for flexible supercapacitors is a timeconsuming process, which is not practical for high-throughput production [3, 4]. Furthermore, the volumetric energy densities would still need to be improved significantly [5]. Carbon nanotubes (CNTs) are a promising material for making electrodes for flexible supercapacitors owing to their excellent electrical, optical and mechanical properties [6]. Here, we develop a facile fabrication technique utilizing vertically aligned carbon nanotube (VACNT) carpets, which enable high-throughput fabrication of flexible supercapacitors. Our unique technique ensures a strong adhesion between VACNT carpets and Polydimethylsiloxane (PDMS), which facilitates a stable charge-discharge under varied strain conditions. Such performance characteristics are critical to determine their practicality as flexible supercapacitors [7]. To fabricate flexible substrates with embedded VACNTs, we synthesized VACNTs using lowpressure chemical vapor deposition (LPCVD) into carpet-like structures and transferred them onto a PDMS substrate before fully cured, enhancing the adhesion between VACNTs and PMDS attributed to the viscoelastic property of PDMS. The entire fabrication process is fairly simple and allows a rapid and facile fabrication and integration of VACNT/PDMS substrate. The VACNT structures possess a very high surface area, which is a key for - flexible supercapacitors with a high-capacitance. The electrochemical property of VACNTs on PDMS was measured in 30% KOH using cyclic voltammetry. The measured capacitance of our structure, which has an area of 0.54