Development of a high-throughput test system for continuous electrolysis processes

RWTH Publications (RWTH Aachen)

Abstract

The demand for economically viable electrolysis processes has increased significantly. The application of high-throughput (HT) research represents an efficient approach to significantly reduce development times. However, existing HT platforms in electrochemistry typically support only abstract experimental conditions or are limited to specific processes, significantly restricting their technological potential for research. This work introduces an innovative HT test system for electrolysis processes, developed in collaboration between the Institute of Energy Technologies (IET-1, Forschungszentrum Jülich GmbH) and hte GmbH. The system enables fully automated, simultaneous screening in 16 parallel-operated flow cells. The extensive system instrumentation and a specially developed cell design, aligned with commercial standards, enable operation under industrially relevant conditions. Furthermore, the system is designed for high variability, supporting all relevant low-temperature water or CO$_2$ electrolysis processes and standard electrochemical measurement techniques. In this thesis, scientific work packages were conceptualized, executed, and analyzed that decisively contributed to the development of the HT system. Validation experiments are conducted on a single cell prototype to validate main cell functions and configurations and to identify optimization potentials. The implementation of a four-terminal sensing method and application of precious metal coatings to the current collectors improves measured cell performance by 12.4 and 10.6 %, respectively. Additionally, the impact of further optimizations, such as alternative current collector materials or reduced electrode spacing, is discussed. Model-based stray current estimations for the HT system with a common electrolyte supply for all 16 cells indicate that the total stray current can be reduced from 187 to less than 2 mA under the tested conditions. However, a comprehensive analysis reveals that fully separated electrolyte circuits are preferable due to various advantages. Corrosion studies with different electrolytes on austenitic stainless steel reveal a high contamination risk. Therefore, in the HT system only inert polymers are used for electrolyte-contacting components. Finally, main system functions are validated through the operation of a 4-fold system prototype. The 4-fold study demonstrates good reproducibility, with a standard deviation of the cell voltage during alkaline water electrolysis of only 14.7 mV at 500 mA/cm$^2$.

Authors 1

1. Deniz Dogan corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen