TY - JOUR

T1 - YSZ-rGO composite ceramics by spark plasma sintering

T2 - The relation between thermal evolution of conductivity, microstructure and phase stability

AU - Glukharev, Artem

AU - Glumov, Oleg

AU - Temnikova, Maria

AU - Shamshirgar, Ali Saffar

AU - Kurapova, Olga

AU - Hussainova, Irina

AU - Konakov, Vladimir

N1 - Funding Information: Research work was supported by the Russian Science Foundation (RSF, project 18-19-00255 ). The sintering was supported by the Estonian Research Council (project PRG643 ). SEM and EDX measurements were performed at the Research park of St. Petersburg State University Interdisciplinary Resource center for Nanotechnology. EBSD analysis was performed at the Center for Geo-Environmental Research and Modeling (GEOMODEL) of the Research park of St. Petersburg State University. The preparation of samples for EBSD were performed «Center for Nanofabrication of Photoactive Materials (Nanophotonics)» at the Research park of St. Petersburg State University. High resolution XRD studies were performed at the Center for X-ray Diffraction Studies of St Petersburg State University. Publisher Copyright: © 2020 Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2021/1/1

Y1 - 2021/1/1

N2 - Despite a high demand for green energy sources, low performance of solid oxide fuel cells (SOFC) hinders the potential for its practical application. Zirconia-graphene composites are promising candidates as solid electrolytes for SOFC enabling efficient heat transfer and effective ion charge carriers movement. Herein, we report the change in electrochemical behavior of spark plasma sintered zirconia-reduced graphene oxide (YSZ-rGO) composites. The conductivity is shown to be altered from fully ionic to mixed electronic-ionic mode upon a small amount of rGO addition. Mixture of freeze-dried nano-sized yttria stabilized cubic zirconia (YSZ) powder and microwave sintered reduced graphene oxide (rGO) was utilized for the fabrication of YSZ-rGO ceramic composites. According to SEM and EBSD data, addition of rGO resulted in a bi-modal grain size distribution. The material with 2 wt.% rGO has demonstrated a mixed electron-ion conductivity in a wide temperature range of 294–1073 K in thermal cycling experiments at oxygen partial pressure of 10−3–10−5 atm, where oxygen ion conductivity dominates over electronic one at elevated temperatures. The electrochemical stability of YSZ-2 wt.% rGO was tested by thermal cycling in nitrogen and argon atmospheres via impedance spectroscopy at 473–1073 K. The model to describe the conductivity evolution with temperature and thermal cycling has been suggested for the first time.

AB - Despite a high demand for green energy sources, low performance of solid oxide fuel cells (SOFC) hinders the potential for its practical application. Zirconia-graphene composites are promising candidates as solid electrolytes for SOFC enabling efficient heat transfer and effective ion charge carriers movement. Herein, we report the change in electrochemical behavior of spark plasma sintered zirconia-reduced graphene oxide (YSZ-rGO) composites. The conductivity is shown to be altered from fully ionic to mixed electronic-ionic mode upon a small amount of rGO addition. Mixture of freeze-dried nano-sized yttria stabilized cubic zirconia (YSZ) powder and microwave sintered reduced graphene oxide (rGO) was utilized for the fabrication of YSZ-rGO ceramic composites. According to SEM and EBSD data, addition of rGO resulted in a bi-modal grain size distribution. The material with 2 wt.% rGO has demonstrated a mixed electron-ion conductivity in a wide temperature range of 294–1073 K in thermal cycling experiments at oxygen partial pressure of 10−3–10−5 atm, where oxygen ion conductivity dominates over electronic one at elevated temperatures. The electrochemical stability of YSZ-2 wt.% rGO was tested by thermal cycling in nitrogen and argon atmospheres via impedance spectroscopy at 473–1073 K. The model to describe the conductivity evolution with temperature and thermal cycling has been suggested for the first time.

KW - Impedance spectroscopy

KW - Mixed conductivity

KW - Reduced graphene oxide

KW - Spark plasma sintering

KW - Zirconia composites

KW - GRAPHENE OXIDE

KW - ZIRCONIA

KW - REDUCTION

KW - MECHANISMS

UR - http://www.scopus.com/inward/record.url?scp=85097353214&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2020.137533

DO - 10.1016/j.electacta.2020.137533

M3 - Article

AN - SCOPUS:85097353214

VL - 367

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

M1 - 137533

ER -