Hydrogen storage properties of nanostructured graphite-based materials

Mechanical milling is an effective way of making defective structures and of the mixing with additions. In this work, the effect of milling conditions and additions on the microstructure and hydrogen storage properties of graphite milled in a tungsten carbide pot was investigated using TGA, Mass Spectrometries, XRD, SEM, HRTEM, Sieverts-PCT and Raman spectroscopy. The TGA and MS results showed that, for a graphite sample milled in hydrogen for 10 hours, the amount of hydrogen desorbed was about 5.6 wt%, and the onset desorption temperature was about 400°C. No methane release could be detected up to 12 hours milling time. HRTEM showed that the interlayer distance increased from 0.34 nm to 0.53nm after milling for 10 hours, and then decreased to 0.48 nm after further milling (40 hours). This paper will discuss how the milling conditions effect both the structure of the graphite samples and their hydrogen storage properties.