PEPR project
SOC (Solid Oxide Cell) fuel flexibility
Dates:
June 2022 – May 2027
Project coordinators:
Annie LE GAL LA SALLE (ST2E team)
Partner laboratories:
11 academic laboratories
IMN staff involved:
Olivier JOUBERT, Clément NICOLLET, Eric QUAREZ
Hydrogen-to-electricity conversion in polymer membrane fuel cell systems is currently at a high level of technological maturity, but requires very high purity hydrogen. High-temperature ceramic membrane fuel cells (SOC: Solid Oxide Cell) with anionic or protonic conduction, although less mature, enable the use of a variety of fuels, and can operate in reversible mode, alternating between electrolyzer and generator functions. The aim of the project is therefore to develop a complete cell that is both robust and flexible with regard to fuel, and operates at relatively low temperatures (600°C). The project is structured around several axes, namely the identification of new materials capable of activating internal reforming reactions, while offering good tolerance to the catalyst poisons generally encountered in these systems (CO, soot, H2S), the architecture of electrodes to implement the selected materials, the shaping of electrolyte materials and the assembly of cells with the implementation of interfaces, as well as a modeling approach to optimize the operating conditions of the devices and thus limit fouling.
In practical terms, the development of active catalysts that are stable at lower temperatures than those currently available, with a target carbon formation rate of around 0.5 mgcarbon gcat-1 h-1 at 600°C, will form the first building block of the project. At the same time, fuel electrode materials will be adapted to make them tolerant to a number of pollutants, in particular hydrogen sulfide, with the aim of achieving minimum tolerable values of 3 to 5 ppm by the end of the project. Similarly, the electrolyte part will be optimized, particularly in terms of composition and thickness, with the aim of achieving a maximum thickness of 10-20 microns. The project will also focus on increasing the lifetime of the systems, thanks to complete automated control of the system under different atmospheres, and the development of effective cleaning strategies. For co-generation and heavy mobility, with reforming and desulfurization, the target lifetime in 2024 is 60,000h, with efficiencies of Rdtel > 45% PCI and Rdtth > 25% PCI. In the case of the FLEXISOC project, with a cell that dispenses with these upstream stages, a lifetime of 30,000 h is targeted. Finally, the power density target for the complete cell, which would enable it to perform internal reforming, withstand a H2S content of 5 ppm, and have a satisfactory service life, could be 1 W cm-2 in 2027.
