Graphene‐Based Devices for Hydrogen Storage

Abstract

In the twenty-first century, renewable, environment-friendly, and sustainable alternative energy sources are urgently demanded because of the aggravating energy problems related to fossil fuel consumption and global warming [1, 2]. Among these candidate energy sources, hydrogen has been considered as one of the ultimate clean fuels because of its environmental compatibility, easy production, and nonpolluting properties [3]. However, the storage of hydrogen has been identified as the most difficult challenge. For practical applications, hydrogen storage demands high gravimetric and volumetric densities, fast reaction kinetics, a low H 2 absorption temperature, good reversibility, and low cost. Therefore, much research effort has been focused on how to develop hydrogen storage systems that can satisfy the conditions mentioned above. Current hydrogen storage technologies, such as cryogenic liquid storage, high-pressure gas cells, low-temperature adsorbates, metal hydrides, and chemical storage, have not been able to meet all the industry requirements [4]. To achieve economic feasibility, hydrogen storage materials with high gravimetric and volumetric densities -specified by the Department of Energy targets of 6.0 wt% mass ratio and 45 kg m −3 volumetric capacity by 2010 -need to be developed urgently [5].Undoubtedly, the developments of hydrogen storage techniques strongly depend on achievements of materials science [2]. In order to accomplish such a target, the key aspects are designing novel materials and developing synthesis processes that allow precise control over the structural and chemical characteristics of the material, as well as seeking greener and cost effective material synthesis processes for the widespread utilization of such devices [6,7]. In the past decade, there has been a strong focus on the use of carbon nanotubes (CNTs) for the fabrication of hydrogen energy storage devices. Besides being lightweight, CNTs present many advantages, including a large surface area (up to 1315 m 2 g −1 ) and mass producability. However, many disadvantages have limited its widespread applications, such as the presence of toxic residual metallic impurities that are very difficult to remove and the high manufacturing cost [8].Graphene-based Energy Devices, First Edition. Edited by A. Rashid bin Mohd Yusoff.