Microstructure and electrochemical properties of PrBaCo2O5+δ/Ce0.9Gd0.1O1.95 vertically aligned nanocomposite thin film as interlayer for thin film solid oxide fuel cells

A thin layer of a vertically aligned nanocomposite (VAN) structure of PrBaCo2O5+δ (PBCO) and Ce0.9Gd0.1O1.95 (GDC) between the cathode and the electrolyte was demonstrated by a pulsed laser deposition (PLD) technique for thin film solid oxide fuel cells (TFSOFCs). The VAN structured PBCO/GDC thin film shows high quality epitaxial growth on single crystal SrTiO3 substrate at high deposition temperatures. It also has a lattice matching relation between the PBCO and GDC vertical nanocolumns. The symmetric cells with the VAN interlayer are found to have a lower area specific resistance (ASR) of 2.1 Ω cm2 compared to that of the ones without the interlayer (2.5 Ω cm2) at 400 °C. The maximum power density of the single cell prepared with the VAN interlayer was 151, 263, and 350 mW cm−2, respectively, at 650, 700, and 750 °C with an open circuit voltage (OCV) of 0.88 V at 750 °C. The PBCO/GDC VAN interlayer could perform as a transition layer that enhances adhesion and relieves stress from different thermal expansion coefficients (TECs) and lattice parameters between the cathode and the electrolyte in TFSOFCs.