Optimizing Ni-YSZ microstructure through anodic aluminum oxide substrate pore size modulation for enhanced reversible solid oxide cell performance

Integrating renewable energy sources into the power grid requires the development of efficient, large-scale energy storage systems to address the intermittency and variability of these energy supplies. Reversible Solid Oxide Cells (RSOCs) present a promising solution due to their dual functionality in fuel cell and electrolysis modes. This study investigates the effect of varying the pore sizes of anodic aluminum oxide (AAO) substrates on the microstructural properties and electrochemical performance of Ni-YSZ fuel electrodes in RSOCs. By modulating the pore size of the AAO templates, control over key parameters such as grain size, porosity, and surface roughness of the Ni-YSZ fuel electrodes was achieved. The findings demonstrate that these microstructural parameters significantly influence the fuel electrode's ionic and electronic conductivity, gas diffusion efficiency, and charge transfer reactions. In particular, AAO substrates with optimized pore sizes facilitated the formation of low-tortuosity and high-performance fuel electrodes capable of efficient operation at lower temperatures. This research provides critical insights into designing and optimizing Ni-YSZ fuel electrodes for next-generation RSOCs, contributing to advancing durable and efficient energy storage solutions for large-scale renewable energy systems.