The aim of this study is to develop composite Nafion/GO membranes, varying GO loading, to be used in a Unitized reversible fuel cell comparing its performance with the baseline Nafion. Water uptake, ion exchange capacity (IEC), tensile strength, and SEM (scanning electron microscope) analysis are discussed. The SEM analysis revealed how the GO is homogeneously disposed into the Nafion matrix. The addition of GO improves the membrane tensile strength while reducing the elongation ratio. Water uptake, IEC enhance with the increasing of GO content. Regarding fuel cell mode, the performance is analysed using a polarization curve on a MEA with an effective area of 9 cm2. The composite membrane demonstrated higher mechanical strength, enhanced water uptake so higher performance in fuel cell mode. Despite the power absorbed from the electrolysis is higher when using a composite membrane, the beneficial effect in FC mode resulted in a slightly higher round trip efficiency. The GO-Nafion membrane was not able to maintain its performance with increasing the operating time, so potentially leading to a lower lifetime than the Nafion bare.

In this study, the implementation of a hydrogen microgrid is investigated, considering the integration of H 2 production, storage, and energy conversion to feed a typical end-user. A remote control system has been realized through LabVIEW software, allowing to monitor real-time all the devices and analyze their performances. The integrated system is composed of a PEM electrolyzer (325 W), a storage system based on metal hydrides (two tanks, 54 g of hydrogen each, 1.08 wt%) and an energy converter (PEM Fuel Cell stack, 200 W). A programmable electronic load was used to set a power demand throughout the year, simulating an end-user. Data collected from each component of the micro-grid were used to characterize the energetic performance of the devices, focusing on the H 2 production via electrolyzer, charging cycles of the H 2 storage system, and energy conversion efficiency of the FC stack. Finally, the global efficiency of the microgrid is computed. Even though the system is realized in laboratory scale, this circumstance will not invalidate the significance of the configuration due to modularity of all the technologies that can be easily scaled up to realistic scales.