• Energy Research

Fuel cell technology development is one of the main activity at CNR-TAE Institute. The reached experience on polymer electrolyte fuel cell (PEFC), especially on electrodes evolution, optimisation and characterisation of membrane-electrodes assemblies (MEAs) and new membrane research, has given the opportunity to start with a project addressed to the realization of a small size PEFC stack. First goal of this work was the development of 100 W stack prototype based on low Pt loading electrodes evolved at CNR-ITAE and working at low pressure. In this work our experience on stack evolution and performance obtained using H2/air as fuel and oxidant, respectively, is reported. The stack with 50 cm2 cells size was designed to produce a rated power of 100 W and a potential of 6 V. MEAs with a total Pt loading of 0.5 mg/cm2 and Nafion® 115 membranes were used. Humidifying conditions for fuel and oxidant based on water amount were studied at a working temperature of 80°C. The experimental activity was finalized to study the optimal operative conditions as a function of gases flux and water amount at 1.5 abs. bar for both fuel and oxidant. A monitoring system of several parameters for each cell was a valid help to associate the stack failure to reagents management problems.

In this work, iodine-doped graphene (I-Gr) was successfully prepared using the electrophilic substitution method and was characterized using micro-Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. I-Gr was integrated into a cathode electrode, as microporous layer. A simple, time-efficient and reliable test protocol was employed for the screening of the new cathode catalyst layers for the PEM fuel cell. A new approach on an aggressive accelerated degradation testing (ADT) protocol along with the monitoring of electrochemical performances response was introduced in order to investigate the degradation. The 400 cycle's operation, totalizing 100 h, was performed for specific sequences of current cycling steps. Electrochemical performances, including polarization curves (I-V), electrochemical surface area (ECSA), and linear sweep voltammetry (LSV) were measured and analyzed every 25 h in order to investigate the performance decreasing trend during the proposed ADT. This reported 100 h test provides very limited information and requires further investigation.

Membranes based on a new sulfonated polysulfone co-polymer having a pending lactone cardo group in one of the structural units were characterized by ion-exchange capacity, water-up take, thermogravimetric analysis and differential scanning calorimetry. This sulfonated polysulfone co-polymer is characterized by a low glass transition temperature (138degreesC). Single cell tests in H-2/air fuel cells configuration at 30 and 60degreesC have shown for 120 mum membranes power densities of 140 and 210 mWcm(-2) respectively. A stable time performance was measured up to 250 hours.

Polymer Electrolyte Membrane Fuel Cells (PEMFC) are arguably the most employed fuel-cell types in various industry sectors, as they operate at low temperature and exhibit short start-up time and high durability. PEMFC manufacturing is currently transitioning from low-volume to mass production. Within this effort, efficient catalyst deposition to produce MEA (Membrane Electrode Assembly) electrodes has become instrumental, since very expensive raw materials are involved. This work focuses on an Additive Manufacturing (AM) technique - a modified 3D printing approach - used to release catalytic inks onto PEMFC electrodes. Some catalyst-free suspensions were designed to resemble a catalytic ink and characterized to assess their printability by microextrusion. Mixtures of distilled water, ethanol and graphite were prepared and tested. Granulometric and rheometric analyses were conducted to optimize the composition towards low viscosity values and short drying time. Repeatability of the released amount and its homogeneousness onto the target surface were evaluated. The most suitable ink formulation was loaded with platinum, a perfluorosulfonic ionomer, a pore former (NHCO) and deposited onto Gas Diffusion Layers (GDL). Scanning Electron Microscopy (SEM) measurements were performed on the 3D-printed electrodes to characterize it. Preliminary electrochemical fuel-cell tests were carried out towards a comparison with conventional electrodes: the proposed deposition technique appears able to produce electrodes that align with state-of-the-art performance level.

The use of Cs0.5H0.5PW12O40 insoluble salt as a superacid promoter in the catalyst layer of a polymer electrolyte membrane fuel cell (PEMFC) has been investigated. An increase of performance has been recorded at intermediate temperatures (110–130 °C) and under low relative humidity (R.H.). The promoter appears to mitigate the ionomer dry-out effects in the catalytic layer and produces an increase of the extent of the catalyst-electrolyte interface as demonstrated by cyclic voltammetry analysis. These effects are also corroborated by a significant decrease of polarization resistance at intermediate temperatures. Such characteristics have been demonstrated for a conventional membrane-electrode assembly based on a Pt-Co alloy and a Nafion 115 membrane.

Fuel cell technology development is one of the main activities at the CNR-TAE Institute. The matured experience on polymer electrolyte fuel cells (PEFC), especially on electrodes evolution, optimisation and characterisation of membrane-electrodes assemblies (MEAs) and new membrane research, has provided the opportunity to start with a project addressed to the realization of a small size PEFC stack. The first goal of this work was the development of a 100 W stack prototype based on low Pt loading electrodes evolved at CNR-ITAE and working at low pressure. This work reports our experience on stack evolution and performance obtained using H2/air as fuel and oxidant, respectively. The stack with 50 cm2 cells size was designed to produce a rated power of 100 W and a potential of 6 V. MEAs with a total Pt loading of 0.5 mg/cm2 and Nafion® 115 membranes were used. Humidifying conditions for fuel and oxidant based on water amount were studied at a working temperature of 80°C. The experimental activity was finalized to study the optimal operative conditions as a function of gases flux and water amount at 1.5 abs bar for both fuel and oxidant. A monitoring system of several parameters for each cell was a valid help to associate the stack failure with reagent management problems.