Single layer low-temperature SOFC based on Ce0.8Sm0.2O2-δ- La0.25Sr0.75Ti1O3-δ-Ni0.8Co0.15Al0.05LiO2-δ composite material

Abstract

This study reports a kind of single layer solid oxide fuel cell (SLSOFC) based on semiconductor-ionic conductor composite material which consists of Ce0.8Sm0.2O2-δ (SDC, ionic conductor), La0.25Sr0.75Ti1O3+δ (LST, n-type semiconductor) and Ni0.8Co0.15Al0.05LiO2-δ (NCAL, p-type semiconductor). It was found that the LST-SDC-NCAL composite based SLSOFC exhibited open circuit voltage (OCV) of more than 1 V and maximum power density of 222 mW cm−2 under 550 °C. In-situ Schottky junction in the device helps to prevent short circuiting as well as promote ion transport. Electrochemical impedance spectroscopy (EIS) analysis revealed that the ionic conductivity of the SLSOFC was about 0.09 S cm−1, and the corresponding activation energy is 0.7 eV. The cell performance was stable during 65 h without any significant degradation. Moreover, the SLSOFC possessed higher tolerance for temperature change than traditional three-layer SOFC due to the well match of thermal expansion coefficient between electrodes and electrolyte. This device is of great significance in preventing fuel cell delamination, simplifying manufacturing process and promoting its commercialization.