Carbon Nanotubes as Future Energy Storage System

Page 1

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Carbon Nanotubes as Future Energy Storage System1 V. Vasu1, D. Silambarasan1 1 – School of Physics, Madurai Kamaraj University, Madurai, India DOI 10.2412/mmse.52.18.599 provided by Seo4U.link

Keywords: carbon nanotubes, metal oxides, hydrogen, storage.

ABSTRACT. Hydrogen is considered to be a clean energy carrier. At present the main drawback in using hydrogen as the fuel is the lack of proper hydrogen storage vehicle, thus on-going research is focused on the development of advance hydrogen storage materials. Many alloys are able to store hydrogen reversibly, but the gravimetric storage density is too low for any practical applications. Theoretical studies have predicted that interaction of hydrogen with carbon nanotubes is by physisorption of hydrogen on the exterior and in the interior surfaces. Hence the CNTs appear to be the ultimate solution due to their chemical stability, large surface area, low density and hollowness. Recent studies indicate that the physisorption on pure CNTs may not be a feasible method of storing hydrogen. Hence, the functionalization of CNTs with metal hydrides is a subject of increasing scientific interest, to improve the hydrogen storage capacities. Lithium borohydride is a complex hydride that is received considerable attention due to its high gravimetric and volumetric hydrogen storage capacities. Our experimental investigation deals with the hydrogenation of SWCNTs functionalized with borane and also we have studied SWCNTs with different metal oxides composite like TiO2, SnO2 and WO3. SWCNTs functionalization with borane was carried out by drop casting method. SWCNTs-metal oxide composite was prepared by both drop casting method and electron beam evaporation method. These results were discussed in detail in the present work. Studies were carried out with the aim to achieve higher storage capacity of hydrogen. It is found that the maximum storage capacity of 4.77 wt.% was observed for the SWCNTs functionalized with borane. The achieved hydrogen storage capacity in this investigation is close to the U.S. DOE target.

Introduction. Being an efficient energy carrier, hydrogen is believed as the appropriate candidate to meet the energy requirements with the increase in population. It is abundant, environmentally friendly fuel that has the potential to reduce our dependence on fossil fuels, but several significant challenges must be overcome before it can be widely used. The issues are namely, production, storage, transportation, conversion and applications. Hydrogen production and conversion are already technologically viable in the present scenario, but its storage and transportation encounter challenges. This work focuses on the investigations of hydrogen storage. Solid state storage form of hydrogen is considered to be the most appropriate and promising way than other forms such as gaseous and liquid. A nano-technological approach to solve the problem of storing hydrogen on materials is one of the main motivations behind this experimental research drive. Among the nano materials, carbon nano materials are the most and widely investigated candidate for hydrogen storage. CNTs play a major role in the curriculum of hydrogen storage than other forms of carbon nanostructures. Carbon nanotubes (CNTs) are one of the allotropes of carbon with a cylindrical nanostructure. These cylindrical sp2 bonded carbon atoms possess unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. Generally, SWCNTs offer better adsorption and desorption properties than other type of CNTs because of their maximum surface area. Hence, we have chosen SWCNTs for our investigations. The initial investigations carried out (by various group) in bare CNTs for hydrogen storage suggested that CNTs are not an efficient material to store hydrogen for practical applications [1]. However, it has been shown that the addition of functional molecules, atoms and ions with CNTs 1

© 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

MMSE Journal. Open Access www.mmse.xyz 8


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.
Carbon Nanotubes as Future Energy Storage System by MMSE Journal - Issuu