Experimental Testing and Validation of the Mathematical Model for a Self-Humidifying PEM Fuel Cell

This paper presents an experimental testing and validation results for a zero-dimensional self-humidifying PEM (Proton Exchange Membrane) fuel cell stack. The model incorporates major electric and thermodynamic variables and parameters involved in the operation of the PEM fuel cell under different operational conditions. The mathematical equations are modelled by using Matlab-Simulink tools in order to simulate the operation of the developed model with a commercially available 1 kW Horizon (H-1000) PEM fuel cell stack, which is used for the purposes of model validation and tuning of the developed model. The model is mathematically modelled and presented in the recent published work of authors. The observations from model simulations provide sufficient evidence and support to the results and observations obtained from testing 1 kW Horizon (H-1000) PEM fuel cell stack used in this research. The developed model can be used as a generic model and simulation platform for a self-humidifying PEM fuel cell with an output power varying from 50 W to 1 kW, with extrapolation to higher powers is also possible.

Preparation of a self-humidifying membrane electrode assembly for fuel cell and its performance analysis

A novel nano-porous material SiO2-gel was prepared. After being purified by H2O2, then protonized by H2SO4 and desiccated in vacuum, the SiO2-gel, mixed with Nafion solution, was coated between an electrode and a solid electrolyte, which made a new type of self-humidifying membrane electrode assembly. The SiO2 powder was characterized by FTIR, BET and XRD. The surface of the electrodes was characterized by SEM and EDS. The performances of the self-humidifying membrane electrodes were analyzed by polarization discharge and AC impedance under the operation modes of external humidification and self-humidification respectively. Experimental-results indicated that the SiO2 powder held super-hydrophilicity, and the layer of SiO2 and Nafion polymer between electrode and solid electrolyte expanded three-dimension electrochemistry reac-tion area, maintained stability of catalyst layer and enhanced back-diffusion of water from cathode to anode, so the PEM Fuel cell can generate electricity at self-humidification mode. The power density of single PEM fuel cell reached 1.5 W/cm2 under 0.2 Mpa, 70°C and dry hydrogen and oxygen.

Using SiO₂Nanopowders in Anode Catalyst Layer to Improve the Performance of a Proton Exchange Membrane Fuel Cell at Low Humidity

In this study, the transfer method is employed to add hydrophilic SiO2 nanopowders to a Pt/C catalyst ink to form an anode catalyst layer on a proton exchange membrane (PEM). The SiO2-layered membrane electrode assembly improves the performance of the PEM under low- or zero-humidification conditions. When the PEM fuel cell (PEMFC) undergoes electrochemical reaction, the moisture content of the PEM exhibits a substantial influence on the transmission of protons. To ensure the moisture content remains high, an external humidifier is typically employed to humidify the majority of PEMFCs. However, self-humidifying PEMFCs could utilize the water produced by the fuel cell reaction, thereby eliminating the need for an external humidifier. In this study, various SiO2 loadings were added to an anode catalyst layer, and the cell temperature and gas humidification conditions were adjusted to determine the influence of the SiO2 loadings on the fuel cell performance. The results show that adding SiO2 is preferable to not adding SiO2 when the fuel cell temperature is 50°C.