Effect of Cu doping on the electrochemical properties and structural phases of La0.8Sr0.2Mn1−xCuxO3 (0≤x≤0.2) at elevated temperature

• Published in: Solid state ionics 2014-07, Vol.260, p.30-35
• Main Authors: Noh, Taimin, Ryu, Jiseung, O'Hayre, Ryan, Lee, Heesoo
• Format: Article
• Language: English
• Subjects: Area specific resistance; La0.8Sr0.2Mn1 − xCuxO3 (0 ≤ x ≤ 0.2); Oxygen reduction reaction; Phase transition; Solid oxide fuel cell; Valence change
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2014.03.012

The electrochemical properties of La0.8Sr0.2Mn1−xCuxO3 (0≤x≤0.2)–Gd0.2Ce0.8O2−δ (GDC) composite cathodes are determined in the intermediate-temperature range (600–850°C), and their cathode performance is analyzed in the context of their phase transition behavior at elevated temperatures. The addition of Cu to LSM forces Mn3+ to Mn4+, thereby increasing the Mn4+ concentration with increasing Cu doping. The increased Mn4+ concentration increases the cubic phase fraction, and thus enhances the low-temperature performance of the LSM cathode. The La0.8Sr0.2Mn0.8Cu0.2O3–GDC yields the greatest low-temperature cubic phase fraction and shows the smallest area specific resistance (0.49Ωcm2 at 750°C) of the compositions tested. •The addition of Cu to LSM increased the Mn4+ concentration.•The increased Mn4+ promoted the rhombohedral-to-cubic phase transformation.•The additional Mn4+ led to the generation of additional oxygen vacancies.•Cu doping improved the electrode performance of the LSM cathode.