scholarly journals Effect of Y/Mg Ion Ratio and Phase Assemble on Ionic Conductivity of ZrO2 Solid Electrolyte Ceramics

2020 ◽  
Author(s):  
Y.G. Hoo ◽  
Jianzhong Xiao ◽  
Feng Xia
Keyword(s):  
Ionic Conductivity ◽  
Grain Boundary ◽  
Solid Oxide Fuel Cells ◽  
Solid Electrolyte ◽  
Electrical Resistance ◽  
Solid Electrolytes ◽  
Design Principle ◽  
Solid Oxide ◽  
Zirconia Ceramic ◽  
Ionic Ratio

Abstract The phase composition design principle is introduced to obtain a balanced properties of ionic conductivity and thermo-tolerant for zirconia solid electrolyte used in solid oxide fuel cells (SOFCs). The zirconia ceramic solid electrolytes were fabricated by two-step sintering. With increasing Y/Mg ionic ratio from 1.78:1 to 1.88:1, the content of monoclinic phase was not fluctuated widely. The ionic conductivity, including the total electrical resistance; grain electrical resistance and grain boundary electrical resistance at 1223K, was gradually declining with increasing of Y/Mg ionic ratio. Furthermore, the enrichment of Mg ion in grain boundary acts as a disincentive to grain boundary ionic conductivity. In addition, the maximum ionic conductivity at high temperature in this study reaches to 0.143 Scm-1 with increase of the Y/Mg ion ratio.

scholarly journals Effect of Y/Mg Ion Ratio and Phase Assemble on Ionic Conductivity of Multi-Doped Zirconia Ceramic Solid Electrolytes

2018 ◽  
Author(s):  
Y.G. Hoo ◽  
Yusheng Shi ◽  
Wenzhong Lu
Keyword(s):  
Ionic Conductivity ◽  
Grain Boundary ◽  
Solid Oxide Fuel Cells ◽  
Electrical Resistance ◽  
Solid Electrolytes ◽  
Design Principle ◽  
Solid Oxide ◽  
Zirconia Ceramic ◽  
Equivalent Conductivity ◽  
Ionic Ratio

The phase composition design principle is introduced to obtain balanced properties of ionic conductivity and thermo-tolerant for zirconia solid electrolytes used in solid oxide fuel cells (SOFCs). The zirconia ceramic solid electrolytes are fabricated by two-step free sintering. With increasing Y/Mg ionic ratio from 1.78:1 to 1.88:1, the content of monoclinic phase fluctuates little (±3%). The ionic conductivity, including the total electrical resistance; grain electrical resistance and grain boundary electrical resistance at 1223K, are all gradually declining with the increasing of Y/Mg ionic ratio. Furthermore, the enrichment of Mg ion in grain boundary acts as a disincentive to grain boundary ionic conductivity. In addition, the maximum total equivalent conductivity at 1223K in this study reaches to 0.143 Scm-1 which can compare with that of certain YSZ. It will be beneficial to SOFCs application profited from increasing ionic conductivity of ceramic solid electrolytes.

scholarly journals A Bulk-Heterostructure Nanocomposite Electrolyte of Ce0.8Sm0.2O2-δ–SrTiO3 for Low-Temperature Solid Oxide Fuel Cells

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yixiao Cai ◽  
Yang Chen ◽  
Muhammad Akbar ◽  
Bin Jin ◽  
Zhengwen Tu ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Short Circuit ◽  
Solid Oxide ◽  
Superior Performance ◽  
Electrode Polarization ◽  
Oxide Fuel ◽  
Ac Impedance Analysis

AbstractSince colossal ionic conductivity was detected in the planar heterostructures consisting of fluorite and perovskite, heterostructures have drawn great research interest as potential electrolytes for solid oxide fuel cells (SOFCs). However, so far, the practical uses of such promising material have failed to materialize in SOFCs due to the short circuit risk caused by SrTiO3. In this study, a series of fluorite/perovskite heterostructures made of Sm-doped CeO2 and SrTiO3 (SDC–STO) are developed in a new bulk-heterostructure form and evaluated as electrolytes. The prepared cells exhibit a peak power density of 892 mW cm−2 along with open circuit voltage of 1.1 V at 550 °C for the optimal composition of 4SDC–6STO. Further electrical studies reveal a high ionic conductivity of 0.05–0.14 S cm−1 at 450–550 °C, which shows remarkable enhancement compared to that of simplex SDC. Via AC impedance analysis, it has been shown that the small grain-boundary and electrode polarization resistances play the major roles in resulting in the superior performance. Furthermore, a Schottky junction effect is proposed by considering the work functions and electronic affinities to interpret the avoidance of short circuit in the SDC–STO cell. Our findings thus indicate a new insight to design electrolytes for low-temperature SOFCs.

Long-Term Electric Conductivity of (Nb,Y)-Doped Bi2O3 Solid Electrolytes for Solid Oxide Fuel Cells

2012 ◽  
Vol 509 ◽  
pp. 111-113 ◽  
Author(s):  
Wen Cheng J. Wei
Keyword(s):  
Phase Transformation ◽  
Solid Oxide Fuel Cells ◽  
Electric Conductivity ◽  
Solid Electrolytes ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Surface Evaporation ◽  
Delta Phase ◽  
Phase Retention

Two oxides, Y2O3 and Nb2O5, were doped into Bi2O3-based electrolyte in a composition of (Bi 1-x-y,Nb x,Y y)2O 3, where (x+y)=0.12 to 0.2 and the x:y ratio 3:1 to 1:3. The delta-phase retention, the oxygen vacancy order-disorder transformation, the ionic and electric conductivity were investigated by various techniques. The long-term conductivity of the dense electrolytes was determined showing moderate degradation due to phase transformation possible triggered by surface evaporation of Bi-oxide. The best retention of the conductivity is about 60% after 300 hr test.

scholarly journals Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2277
Author(s):  
Zhengwen Tu ◽  
Yuanyuan Tian ◽  
Mingyang Liu ◽  
Bin Jin ◽  
Muhammad Akbar ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Ionic Conduction ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Open Circuit Voltages ◽  
Composite Samples

Recently, appreciable ionic conduction has been frequently observed in multifunctional semiconductors, pointing out an unconventional way to develop electrolytes for solid oxide fuel cells (SOFCs). Among them, ZnO and Li-doped ZnO (LZO) have shown great potential. In this study, to further improve the electrolyte capability of LZO, a typical ionic conductor Sm0.2Ce0.8O1.9 (SDC) is introduced to form semiconductor-ionic composites with LZO. The designed LZO-SDC composites with various mass ratios are successfully demonstrated in SOFCs at low operating temperatures, exhibiting a peak power density of 713 mW cm−2 and high open circuit voltages (OCVs) of 1.04 V at 550 °C by the best-performing sample 5LZO-5SDC, which is superior to that of simplex LZO electrolyte SOFC. Our electrochemical and electrical analysis reveals that the composite samples have attained enhanced ionic conduction as compared to pure LZO and SDC, reaching a remarkable ionic conductivity of 0.16 S cm−1 at 550 °C, and shows hybrid H+/O2− conducting capability with predominant H+ conduction. Further investigation in terms of interface inspection manifests that oxygen vacancies are enriched at the hetero-interface between LZO and SDC, which gives rise to the high ionic conductivity of 5LZO-5SDC. Our study thus suggests the tremendous potentials of semiconductor ionic materials and indicates an effective way to develop fast ionic transport in electrolytes for low-temperature SOFCs.

A Multiphysics Modeling Study of (Pr0.7Sr0.3)MnO3±δ∕8mol% Yttria-Stabilized Zirconia Composite Cathodes for Solid Oxide Fuel Cells

2004 ◽  
Vol 2 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ke An ◽  
Kenneth L. Reifsnider
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Solid Oxide Fuel Cells ◽  
Current Density ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Oxide Fuel ◽  
Stabilized Zirconia ◽  
Before And After

Solid oxide fuel cells (SOFCs) are expected to be a future power source. Simulation analyses of SOFCs can help to understand well the interactive functions among the multiphysics phenomena in the SOFC system. A three-dimensional multiphysics finite-element model was used to simulate the performance of a half-cell SOFC with (Pr0.7Sr0.3)MnO3±δ∕8mol% yttria-stabilized zirconia (8YSZ) composite cathode on one side of the 8YSZ electrolyte before and after aging. Multiphysics phenomena in the SOFC were considered in the modeling. The current/voltage curves simulated matched the experimental data before and after aging. The average current density was found to have a linear relationship to the logarithm of the effective exchange current density. The effect of the effective ionic conductivity of the composite cathode was more apparent for small total effective ionic conductivity values than for large ones.

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