Journal of Solid State Chemistry ( IF 3.3 ) Pub Date : 2020-06-25 , DOI: 10.1016/j.jssc.2020.121530 Zheyu Zhang , Kalpana Singh , Yoed Tsur , Jigang Zhou , James J. Dynes , Venkataraman Thangadurai
In this study, effect of Ca-doping on electrical and electrochemical properties of garnet structure Y3-xCaxFe5O12-δ (x = 0, 0.05, 0.1, 0.3, 0.5 and 0.7) was investigated. Cubic-phase (Ia-3d) garnet was prepared through sol-gel method and final sintered at 1100 °C for 2 h in air. Highest oxygen non-stoichiometry (δ = 0.19) was found in x = 0.3 member. X-ray absorption spectroscopy (XAS) confirmed the formation of hole carriers () due to Ca-substitution for Y in Y3Fe5O12.4-Probe DC measurements showed electrical conductivity increased with an increase in Ca amount until x = 0.1 (1.58 S/cm at 750 °C) and then decreased due to decrease in the concentration of the charge carriers. Lowest area specific resistance (ASR) of 1 Ωcm2 was seen at 750 °C in air for the symmetrical cell with x = 0.3 garnet-LSGM composite electrode. Studies on pO2 dependent ASR and impedance spectroscopy genetic programming (ISGP) analysis revealed oxygen dissociation and partial reduction of adsorbed oxygen molecule co-limit the electrochemical performance of oxygen reduction reaction (ORR) of this electrode.
中文翻译:
钙掺杂对石榴石型Y 3-x Ca x Fe 5 O12 -δ结构和电化学性能的影响
在这项研究中,研究了钙掺杂对石榴石结构Y 3-x Ca x Fe 5 O12 -δ(x = 0、0.05、0.1、0.3、0.5和0.7)的电和电化学性能的影响。通过溶胶-凝胶法制备了立方相(Ia-3d)石榴石,并在1100°C下于空气中最终烧结2 h。 在x = 0.3的成员中发现了最高的非化学计量比的氧(δ = 0.19)。X射线吸收光谱(XAS)证实了空穴载流子的形成()由于在Y 3 Fe 5 O 12 .4探针中用Y取代了Ca,所以直流测量表明电导率随着Ca含量的增加而增加,直到x = 0.1(在750°C下为1.58 S / cm),然后由于降低载流子的浓度。1Ωcm以下的最低面积比电阻(ASR)2在750℃下被认为在空气中,其中x = 0.3石榴石LSGM复合电极的对称的细胞。对依赖于pO 2的ASR和阻抗谱遗传编程(ISGP)分析的研究表明,氧离解和吸附的氧分子的部分还原共同限制了该电极的氧还原反应(ORR)的电化学性能。