Preparation and porosity optimization of porous copper fiber sintered felt for coupling with a PEM water

Abstract

Porous copper fiber sintered felt (PCFSF) is a promising ribless flow field material for proton exchange membrane fuel cells (PEMFCs). To improve its performance, it is essential to understand the preparation process and to optimize the porosity. After obtaining PCFSF with good properties, coupling it with a PEM water electrolysis system allows on-site hydrogen production and immediate use, forming a complete power generation chain. In this work, PCFSF samples with porosities ranging from 60% to 90% were prepared by low-temperature solid-state sintering. Fuel cell performance tests showed that the 70% porosity sample gave the best results. The reasons for performance degradation at excessively high porosity, namely reduced electrical conductivity and lower mechanical strength, were analyzed. On this basis, a PEM water electrolysis system was built, which delivered a stable hydrogen production rate of 400 mL/min at a constant current of 26 A. Capacity matching analysis based on Faraday’s law showed that this system can support a fuel cell to reach a theoretical limiting current density of about 2.16 A/cm2. Within the range of 0–2.16 A/cm2, a dynamic balance between hydrogen production and consumption can be achieved. This work covers the whole chain from material preparation to porosity optimization and system coupling, providing a reference for the practical application of porous metal bipolar plates and the integrated design of distributed hydrogen energy systems.