Abstract

The increasing awareness of the adverse impact of green-house gas emissions, mostly carbon dioxide (CO2), on the environment and human health has accelerated the global push for sustainable energy solutions. Solid oxide cells (SOCs) have emerged as a promising electrochemical energy conversion and storage device, especially for large-scale applications, due to their high efficiency, fuel flexibility, and reversibility between fuel cell and electrolysis modes. However, the high operational temperature poses durability challenges, and lowering the operating temperature significantly reduces the catalytic activity, particularly in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) occurring in air electrodes. Perovskite-based oxides (ABO3) are commonly employed as the air electrode owing to their high electrochemical kinetics and decent chemical stability in oxidizing environment.
   In this dissertation, I demonstrate that an angstrom-level thin oxide overcoat by atomic layer deposition (ALD) on perovskite-based air electrodes can simultaneously address two key degradation processes: electrode agglomeration and dopant segregation toward surface, while enhancing the electrocatalytic activity for both ORR and OER. The overcoat provides enhanced surface chemical kinetics and mechanical stabilization and suppresses the agglomeration of the perovskite nanoparticles, while simultaneously limiting dopant segregation toward the electrode surface. My research highlights the potential of surface engineering to effectively enhance the performance and durability of both solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs).

Biography

Haoyu Li is a Ph.D. candidate in the Department of Mechanical Engineering. He joined Prof. Min Hwan Lee’s l(E2C) Lab at fall of 2017 and has since been working under his supervision to study oxygen reduction/evolution reaction (ORR/OER) and durability of SOCs. He utilized ALD as the tool to facilitate the cell performance and enhance the durability. He is also actively involved in the development of solid oxide electrolysis cell (SOEC) test apparatus to expand his research scope. He obtained his bachelor’s degree in physics from Drew University.