Macroscale evaluation and testing of chemically hydrogenated graphene for hydrogen storage applications

Abstract

The effective storage of H2 gas represents one of the major challenges in the wide spread adoption of hydrogen powered fuel cells for light vehicle transportation. Here, we investigate the merits of chemically hydrogenated graphene (graphane) as a means to store high-density hydrogen fuel for on demand delivery. In order to evaluate hydrogen storage at the macroscale, 75 g of hydrogenated graphene was synthesized using a scaled up Birch reduction, representing the largest reported synthesis of this material to date. Covalent hydrogenation of the material was characterized via Raman spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). We go on to demonstrate the controlled release of H2 gas from the bulk material using a sealed pressure reactor heated to 600 °C, identifying a bulk hydrogen storage capacity of 3.2 wt%. Additionally, we demonstrate for the first time, the successful operation of a hydrogen fuel cell using chemically hydrogenated graphene as a power source. This work demonstrates the utility of chemically hydrogenated graphene as a high-density hydrogen storage medium, and will be useful in the design of prototype hydrogen storage systems moving forward.