Fabrication of thin and dense GDC buffer layers: enhancing cathode performance in SOFCs

Abstract

As global energy demand rises, solid oxide fuel cells (SOFCs) are emerging as promising technologies for clean hydrogen energy conversion due to their high efficiency and fuel flexibility. However, cathode–electrolyte interfacial instability remains a major challenge, particularly in next-generation fuel cells such as metal–supported (MS) SOFCs operating at intermediate temperatures. Conventional ceria buffer layers, essential for preventing cathode–electrolyte reactions, suffer from poor densification, excessive thickness, and high sintering temperatures (above 1300 °C), limiting their industrial applicability. This study presents a novel low-temperature fabrication method using ultra-nano (∼3 nm) Gd-doped ceria particles, achieving a dense (∼99%) and ultra-thin (<400 nm) buffer layer at 900–1000 °C. This development eliminates Sr and Ba interdiffusion, significantly reducing polarization resistance (∼0.02 Ω cm² at 700 °C) and enabling high power densities (∼1 W cm⁻² at 700 °C in MS-SOFCs). The full cells maintained electrochemical stability over 200 h of constant-current operation and showed negligible degradation after 10 thermal cycles, confirming their operational durability. These findings directly impact energy science and technology, providing a scalable, cost-effective solution for enhancing SOFC efficiency. This work supports global clean energy policies by enabling more durable, high-performance SOFCs, accelerating their commercialization for hydrogen infrastructure, grid stabilization, and industrial decarbonization.