Vertically aligned nanocomposite La0.8Sr0.2MnO3−δ/Zr0.92Y0.08O1.96 thin films as electrode/electrolyte interfacial layer for solid oxide reversible fuel cells

•LSM/YSZ VAN is inserted between conventional LSM/YSZ electrode and electrolyte.•Improved electrochemical properties of oxygen electrode with VAN observed.•The enhancements come from expanded TPBs length and more porous microstructure.•The power output of fuel cells significantly increases by applying VAN interlayer.

A thin layer with a vertically aligned nanocomposite (VAN) structure of La0.8Sr0.2MnO3−δ (LSM) and Zr0.92Y0.08O1.96 (YSZ) between the oxygen electrode and the electrolyte has been fabricated by a pulsed laser deposition (PLD) technique for solid oxide reversible fuel cells (SORFCs). The high quality epitaxial growth of VAN structured LSM/YSZ has been achieved on single crystal SrTiO3 substrate at high-deposition temperatures. The symmetric cells with the VAN interlayer are found to have a lower area specific resistance compared to that without the interlayer. The enhancement in performance has been demonstrated by increased oxygen electrode catalytic properties and porous oxygen electrode microstructure. The cell with the VAN interlayer shows an open circuit voltage (OCV) of 1.00 V at 650 °C and maximum power densities of 0.22, 0.32, 0.43 and 0.55 W cm−2 at 650, 700, 750 and 800 °C, respectively. Compared with the cell without an interlayer, the cells with the interlayer have ∼2 times of the overall maximum power density at the measured temperature range, demonstrating that the VAN interlayer significantly enhances the oxygen electrode performance.