This thesis seeks to experimentally demonstrate the possibility of reversible storage of hydrogen directly into a carbon-based electrode of a PEM unitised regenerative fuel cell. The concept of electrochemical solid-state storage of hydrogen employs some of the principles of battery storage and may be a link between battery technology and fuel cell technology. In this research, composite material of activated carbon and Nafion® was chosen to investigate the potential direct and reversible storage of hydrogen. The ultra-microspores of activated carbon provide the storage sites and Nafion® provides the pathway to guide the hydrogen ions to the storage sites. In total, ten samples of activated carbon were used in this research including five samples that were activated by KOH chemical activation method. The porosity of the samples were characterised by adsorption isotherm of CO2 at 273 K and N2 at 77 K. From the ten activated carbons, five were selected for solution casting of composite materials with Nafion® solution. The physical properties, i.e. water uptake and volume expansion, and electrochemical properties, i.e. proton and electron conduction, of the composite materials were measured as a function of relative humidity. Based on the charge conductions and porosity of activated carbons, two of the composite materials were selected for fabricating the hydrogen storage electrodes. The hydrogen storage electrodes were hot-pressed to Nafion® 115 membrane and oxygen electrode. The oxygen electrodes were loaded with 2 mg/cm2 of IrRuOx and 2 mg/cm2 of Pt as electrocatalysts. The membrane-electrode-assemblies (MEAs) were tested in a specially-made cell in electrolyser and fuel cell modes. Although no noticeable sign of hydrogen storage was seen for the tested samples, valuable experimental data were obtain that could lead to future work. The dual proton electron conduction of the composite materials also promises potential applications in direct solar electrolysis in a photocatalytic system.
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