A novel Nb and Cu co-doped SrCoO3-δ cathode for intermediate temperature solid oxide fuel cells. (1st April 2020)

• Record Type: Journal Article
• Authors: Le, Shiru; Li, Chunfeng; Song, Xueqin; Zhang, Yanxiang; Feng, Yujie; Mao, Yachun; Zhu, Xiaodong; Zhang, Naiqing; Yuan, Zaifang
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 18(2020)
• Page Start: 10862
• Page End: 10870
• Publication Date: 2020-04-01
• Subjects: Solid oxide fuel cell -- Niobium and copper co-doped SrCoO3-δ -- Cathode -- Electrochemical performance; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.01.160
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The extensive explorations of potential cathode materials are prominently critical for the rapid development of high performance solid oxide fuel cells (SOFCs). Herein, we develop a novel Nb and Cu co-doped SrCoO3-δ (SCNC) cathode base on solid state reaction, which exhibits decent compatibility with gadolinium doped cerium oxide (GDC) electrolyte. The SCNC is successfully stabilized with cubic structure at room temperature when incorporating of small amount of high valence Nb 5+ . Meanwhile, the oxygen vacancy concentration of SCNC is efficiently improved with the addition of Cu. The Nb and Cu co-doping also substantially promotes the electronic conductivity, achieving 550 S cm −1 for the optical doped SrCo0.85 Nb0.05 Cu0.10 O3-δ (SCNC10) at 400 °C. In addition, the polarization of SCNC is remarkably reduced, reaching as low as 0.021 Ω cm 2 for SCNC10 at 700 °C. The activation energy for reaction is also significantly lowered to 0.78 eV. The reaction order m is deduced to be about 0.30, implying that the rate determination step for SCNC10 is the charge transfer reaction. The peak power density of the single cell reaches 780 mW cm −2 at 800 °C. All these outstanding performances demonstrate that SCNC is a promising cathode for SOFCs when operating at intermediate temperature (IT). Graphical abstract: (a)The EIS of SCNC10 at different oxygen pressure at 700 °C; (b)the relationship of lnRp to ln (Po2 ) for SCNC10 measured at 700 °C. The reaction order m is about 0.30, suggesting that the RDS for SCNC10 is probably to be the charge transfer reaction. Image 1 Highlights: A novel Nb and Cu co-doped SrCoO3-δ improved its oxygen vacancy concentration. The ASR for SCNC10 was only 0.021 Ω cm −2 at 700 °C, with the activation for reaction is only 0.78 eV. The reaction orders suggest that the rate determine step is probably to be the charge transfer reaction.