Vinchhi Prerna, Ray Abhijit, Mallik Kaushik, Pati Ranjan
Department of Solar Energy, Pandit Deendayal Energy University, Gandhinagar, Gujarat, 382421, India.
Solar Research and Development Center, Pandit Deendayal Energy University, Gandhinagar, Gujarat, 382421, India.
Sci Rep. 2024 Aug 16;14(1):19010. doi: 10.1038/s41598-024-59030-6.
Doped ceria has been extensively explored as an efficient electrolyte material for intermediate to low temperature solid oxide fuel cell. Among other ceria electrolytes, gadolinia doped ceria (GDC) is one of the most extensively studied electrolyte materials for low temperature SOFC applications. Here, co-precipitation method is employed to synthesize GDC nanoparticles with stoichiometric ratio of GdCeO (with 0 x 0.20). In this process, the molecular water of the precursors has been utilized during the co-precipitation to avoid possible agglomeration caused by hydrogen bonding. The cubic phase formation was examined using X-ray diffraction (XRD) and Raman profile ascribing absence of other phases. XRD along with Reitveld refinement confirm the presence of cubic phase of ceria and Raman profile confirms the oxygen vacancies due to the non-stoichiometry created in CeO lattice. The granularity of the sample was observed using field emission scanning electron microscopy (FESEM) with elemental mapping by EDS. It is observed from FESEM that the grains are compact in nature and the density observed was around 98% of the theoretical density. The electrochemical behavior was investigated using electrochemical impedance spectroscopy (EIS), which was taken between the temperature ranges of 350-700 °C. It is observed from the EIS study that ceria doped with 15 mol % Gd (GdCeO) is having highest grain boundary ionic conductivity of about 0.104 S cm at 700 °C with an activation energy of 0.81 eV. This work demonstrates the correlation between oxygen vacancy generation and the enhancement of ionic conductivity with Gd doping in ceria.
掺杂二氧化铈作为中低温固体氧化物燃料电池的高效电解质材料已得到广泛研究。在其他二氧化铈电解质中，钆掺杂二氧化铈（GDC）是低温固体氧化物燃料电池应用中研究最为广泛的电解质材料之一。在此，采用共沉淀法合成化学计量比为GdCeO（0 ≤ x ≤ 0.20）的GDC纳米颗粒。在此过程中，前驱体中的分子水在共沉淀过程中被利用，以避免由氢键引起的可能团聚。使用X射线衍射（XRD）和拉曼光谱检查立方相的形成，确定不存在其他相。XRD结合Rietveld精修证实了二氧化铈立方相的存在，拉曼光谱证实了由于CeO晶格中产生的非化学计量比导致的氧空位。使用场发射扫描电子显微镜（FESEM）观察样品的粒度，并通过能谱仪进行元素映射。从FESEM观察到，颗粒本质上是致密的，观察到的密度约为理论密度的98%。使用电化学阻抗谱（EIS）研究电化学行为，该测试在350 - 700°C的温度范围内进行。从EIS研究中观察到，掺杂15 mol%钆（GdCeO）的二氧化铈在700°C时具有最高的晶界离子电导率，约为(0.104 S cm^{-1})，活化能为(0.81 eV)。这项工作证明了二氧化铈中钆掺杂导致的氧空位产生与离子电导率增强之间的相关性。
