(Invited) The Need for Standardized Benchmarking of Solid Oxide Cells

Abstract

Solid Oxide Cells (SOC) have been the subject of intense scientific research in the past few decades, and significant progress has been achieved to increase the power output. While promising efforts to further industrialize the technology are underway, an increase in the performance of SOCs is still the scope of many scientific publications. However, progress in cell performance is increasingly hard to gauge due to a lack of comprehensive testing standards. Furthermore, many researchers publish performance data without providing all the necessary information about the testing conditions, or use metrics that do not allow comparison to other works.In particular, the “peak power density” (PPD) is often used to characterize cell performance. The PPD is unsuitable as a performance indicator since it is far removed from a relevant working point for an SOFC, and depends to a large extend on the experimental conditions. To make matters worse, the PPD of high-performance cells is located at very high current densities, exacerbating the influence of the experimental conditions (which are often not described in detail or at all) and experimental artifacts on the measured performance. As a result, claims of increased cell performance may not hold up when applying standardized testing criteria.This contribution summarizes the most important aspects that are relevant for performance evaluation of SOCs, focusing on those with the highest impact on apparent cell performance. Furthermore, the limitations of performance indicators on the cell level will be illustrated by comparing them to stack-level performance, and additional losses incurred under application-oriented operation conditions will be discussed. Since cell testing is often the key test to assess performance of novel materials and processing routes, comparability of the results is critical to scientific progress and therefore relevant for the community as a whole.