A Coherent Workflow for Elevating Transition Metal Oxide Anode Materials in Alkaline Electrolysis to Connect Insights from Micro Powder Analysis with Electrochemical Performance
Authors: Vinayakumar Vineetha , Jain Adarsh , Chatwani Mohit , Wagner Timo , Marcks Christian , Wöhrl Nicolas , Mechler Anna K. , Segets Doris 
Published: August 2024

Increasing environmental concerns have redirected research efforts toward sustainable energy, prominently highlighting hydrogen as a promising solution [1]. Despite considerable advancements in water electrolysis, providing efficient energy conversion and storage, there exists a gap in our comprehensive understanding of the production chain. This includes insights from commercial powder materials to electrode fabrication and their electrocatalytic behavior, representing an underexplored domain that demands closer examination.

This study systematically examines transition metal oxide electrocatalysts, aiming to parameterize the process chain within the context of a coherent workflow for advancing transition metal oxide anode materials in alkaline electrolysis. This approach seeks to reveal the interdependencies and comprehend the correlations between material properties, fabrication processes, electrode structure, and the final performance of the cell. Our methodology integrates a range of complementary techniques to ensure a consistent analysis of the physical and chemical properties of the materials. Following the initial characterization of commercial micropowder through transmission electron microscopy and energy-dispersive X-ray spectroscopy, we optimized ink formulations derived from the powder using analytical centrifugation and Hansen parameter calculations [2]. Subsequently, selected inks were transferred to electrodes by coating these inks on Ni plates via ultrasonic spray deposition. We further investigated the impact of post-treatments, including vacuum annealing and surface plasma treatment, on the stability of the electrodes, particularly in terms of delamination prevention.

To quantify the underlying micro features of this wide range of electrode surfaces and analyze their characteristics, we developed a framework called multistage data quantification (MSDQ). MSDQ ulitizes microscopical charcterizations such as laser microscopy and atomic force microscopy [3]. The assessed electrodes were finally tested as anodes for alkaline water electrolysis, revealing correlations between electrode properties and electrochemical activity and stability. In line with the recognized structural characteristics, our initial findings indicate that electrodes treated with plasma demonstrate reduced overpotentials and enhanced stability when compared to pristine and plasma treated electrodes, due to increased adhesion and surface properties (e.g., roughness).

Our study makes a substantial contribution to the comprehensive evaluation of the alkaline water electrolysis system across its development stages, incorporating valuable insights from earlier steps to continually enhance electrode performance. Our approach is particularly advantageous in enabling the transition from laboratory-scale research to scalable processing, effectively bridging the crucial gap for practical industrial applications [4].

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Bapat, S., et al., "On the state and stability of fuel cell catalyst inks. " Advanced Powder Technology, 2021. 32(10): p. 3845-3859.

Jain, A., et al., "Small-Area Observations to Insight: Surface-Feature-Extrapolation of Anodes via Multistage Data Quantification. " Under review, ChemCatChem

Segets, D., et al., "Accelerating CO2 electrochemical conversion towards industrial implementation." Nature communications 14.1 (2023): 7950.