Vineetha Vinayakumar1,2,Adarsh Jain1,Mohit Chatwani1,Timo Wagner3,Christian Marcks4,Nicolas Wöhrl3,2,Anna K. Mechler4,Doris Segets1,2
Institute for Energy and Materials Processes–Particle Science and Technology (EMPI–PST), University of Duisburg–Essen (UDE)1,Center for Nanointegration Duisburg–Essen (CENIDE), University of Duisburg–Essen (UDE)2,Faculty of Physics, University of Duisburg–Essen (UDE)3,Electrochemical Reaction Engineering, RWTH Aachen University4
Vineetha Vinayakumar1,2,Adarsh Jain1,Mohit Chatwani1,Timo Wagner3,Christian Marcks4,Nicolas Wöhrl3,2,Anna K. Mechler4,Doris Segets1,2
Institute for Energy and Materials Processes–Particle Science and Technology (EMPI–PST), University of Duisburg–Essen (UDE)1,Center for Nanointegration Duisburg–Essen (CENIDE), University of Duisburg–Essen (UDE)2,Faculty of Physics, University of Duisburg–Essen (UDE)3,Electrochemical Reaction Engineering, RWTH Aachen University4
The depletion of conventional energy resources has highlighted the need for sustainable alternatives, with hydrogen emerging as a promising option. However, the commercial-scale production of hydrogen remains a challenge (1). In this study, we focus on water electrolysis as an efficient method for energy conversion and storage, emphasizing the crucial role of electrocatalysis. Despite recent progress, establishing direct correlations between anode properties and performance in an industrial setting is crucial for the practical implementation of stable and highly efficient anodes for alkaline water electrolysis at pilot-scale systems. This requires linking the scale-up process with a comprehensive fundamental understanding, enabling successful scaling while maintaining optimal performance.<br/>To address these challenges, we evaluate the cycle of anode generation starting from the characterization of micropowders through catalyst inks to final electrodes. Our primary goal is to achieve efficient hydrogen production on a commercial scale. To accomplish this, our methodology utilizes complementary techniques to thoroughly analyze the physical and chemical properties of materials throughout the entire process chain. By adopting this comprehensive approach, we aim to gain a deep understanding of the materials involved and optimize their performance for the production of hydrogen on a large scale. To evaluate the interdependencies between different stages and to find out the determining steps during electrode manufacturing, we developed a framework in the sense of a coherent workflow starting with the characterization of commercially available Ni- and Co-based micro powders. Subsequently, ink formulations were optimized using analytical centrifugation (2) and Hansen parameter calculations (3), followed by electrode layer fabrication using ultrasonic spray deposition of the ink on Ni plates. After optimizing each individual stage in the whole process chain, we also investigated the influence of post-treatments, specifically vacuum annealing, and surface plasma treatment, on the stability of electrodes against delamination. A framework based on atomic force microscopy was developed to precisely quantify micro features and analyze the surface characteristics of electrodes including large areas. Subsequently, the evaluated electrodes were subjected to functional testing as anodes in alkaline water electrolysis, revealing valuable correlations between the properties of the catalyst ink and coated electrodes with their electrochemical activity and stability. Consistent with the identified structural characteristics, our preliminary results demonstrate that plasma-treated Ni-Co-O electrodes exhibit reduced overpotentials and enhanced stability compared to both pristine and vacuum-annealed electrodes. This improvement can be attributed to the enhanced adhesion and favorable surface properties, including roughness, induced by the plasma treatment. This study contributes significantly to the evaluation of the system throughout its various stages, integrating valuable feedback from preceding steps to further optimize electrode performance. Notably, our approach proves particularly advantageous in facilitating the transition from laboratory-scale developments to scalable processing, bridging the critical gap for practical industrial applications.<br/><br/><b>References</b><br/>(1) Ehlers, J.C., et al., Affordable Green Hydrogen from Alkaline Water Electrolysis: Key Research Needs from an Industrial Perspective. ACS Energy Letters, 2023. <b>8</b>(3): p. 1502-1509.<br/>(2) Bapat, S., et al., On the state and stability of fuel cell catalyst inks. Advanced Powder Technology, 2021. 32(10): p. 3845-3859.<br/>(3) Anwar, O., et al., Hansen parameter evaluation for the characterization of titania photocatalysts using particle size distributions and combinatorics. Nanoscale, 2022. 14(37): p. 13593-13607.