CCS and Power Systems
Advanced Energy Systems - Solid Oxide Fuel Cells
NETL-RUA Fuel Cells Initiative
Performer: NETL's Office of Research and Development
Project No: FWP-2012.03.04
This project is a multi-area investigation aimed at advancing the performance and integration of fuel cells. The project consists of two main areas: Cell and Stack Degradation and Cathode Materials and Microstructural Engineering.
Cell and Stack Degradation: Among stack components, the anode-electrolyte-cathode (AEC) degradation rate is potentially the most influential over the total stack degradation rate. It is also perhaps the most complex in terms of the unique degradative modes, and is also the most susceptible to degradation owing to its central role in the electrochemical process. The AEC is therefore a key component targeted for degradation investigation. Comprehensive models predicting solid oxide fuel cell (SOFC) stack degradation do not exist, or are not sufficiently descriptive to consider all of the primary degradative modes. Due to the complexity and sheer number of degradation processes occurring in the SOFC stack, the present effort to evaluate degradation is initially confined to the AEC structures and materials under commercial consideration. Results of the degradation mode investigation will be incorporated into a computational model that will include only the most prominent degradation modes. Individual degradation modes will be examined with specialized techniques and constituted as mathematical expressions relating dependent AEC parameters (e.g., electrode porosity) to independent operating parameters including operating temperature and local overpotential. This model will provide evolving AEC performance parameter updates on a 40 plus kilohour timescale. Model predictions will be confirmed by comparison to samples prepared in-house and also from samples obtained from industry teams.
A detailed investigation of the degradation modes in the AEC will facilitate targeted efforts to improve fuel cell longevity, ultimately resulting in decreased system costs. Development of a world-class modeling tool will accelerate AEC materials and structure innovation leading to more commercially relevant SOFC technology.
Cathode Materials and Microstructural Engineering: Cathodes are a primary source of the inefficiency observed in a state-of-the-art anode-supported cell operating at temperatures from 750–800 °C. Owing to the relatively high contribution of cathode overpotential to total cell inefficiency, SOFC research to improve cathode performance can help meet critical program targets for cell cost and efficiency. Conventional cathode microstructural engineering is accomplished through careful control of precursor cathode materials. Using conventional methods, limited variability is available in the final cathode structures. New approaches focus on generation of advanced microstructures that are more conducive to species transport, or methods to apply an engineered cathode at lower cost. These research projects will result in full characterization of performance and durability of the proposed technologies at an intermediate scale. Results will be shared with Solid State Energy Conversion Alliance (SECA) industry teams, and the most promising technologies will be selected for further scale-up. Methods developed will generate more functional cathode structures to facilitate enhanced cathode performance, and will potentially allow greater tuning of the final cathode architecture. These research efforts will improve cathode performance, thereby resulting in increased cell efficiency and, ultimately, a diminished system cost. Cathode material and structure innovations developed through these projects should be readily transferable to industry.