Modified Energy Efficiencies of Proton‐conducting SOFCs with Partial Conductions of Oxide‐ions and Holes

Abstract

An analytical method to determine the electrochemical energy efficiencies of electrolytes with partial electronic conduction has been developed previously and reported in the literature. However, this analytical method does not address the effects of differing ionic species in electrolytes, i.e., the oxide‐ions or protons. Therefore, we aimed to modify this analytical method to account for the effects of differing ionic species, and applied it to compare the energy efficiencies of oxide‐ion conducting solid electrolytes such as yttria‐stabilized zirconia (YSZ) and gadolinia‐doped ceria (GDC) to proton‐conducting solid electrolytes, such as yttria‐doped barium zirconate (BZY). With the modification, difference in the influence of the fuel consumption between the oxide‐ion conducting electrolyte and the proton‐conducting electrolyte has been successfully taken into account. The energy efficiency of the BZY electrolyte relatively increased against those of YSZ or GDC electrolytes by the modification. Additionally, partial oxide‐ion conduction in the proton‐conducting electrolyte was successfully estimated using the modified analytical method.

Enhancement of Electrochemical Properties, Impedance and Resistances of Micro‐tubular IT‐SOFCs with Novel Asymmetric Structure Based on BaZr0.1Ce0.7Y0.1Yb0.1O3−δ Proton Conducting Electrolyte

“…The enlarged view is shown in the inset of Figure a, such interfaces are especially suitable for expanding the TPBs length, which can lead to decreased electrodes polarization. The microstructure shown here is similar to the anode | electrolyte interface, as previously presented by our group , , , , . The BZCYYb electrolyte adhered well to the anode substrate, indicating that a thin and dense BZCYYb electrolyte produced by our method that requires a relatively low sintering temperature.…”

“…1.1 eV ), and higher conductivity compared with conventional oxide ion counterparts at intermediate temperature range . Among them, yttrium doped barium cerate proton‐conducting ceramics such as BaCe 0.8 Y 0.2 O 3– δ (BCY) , , BaZr 0.1 Ce 0.7 Y 0.2 O 3– δ (BZCY) , and BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3– δ (BZCYYb) have been widely considered to be most favorable candidates for electrolyte, which exhibit high bulk conductivity at intermediate temperature (450–750 °C) , . As barium zirconate‐cerate was co‐doped with Y and Yb in the compositions of BaZr 0.1 Ce 0.7 Y 0.2– x Yb x O 3– δ ( x = 0 to 0.2), these elements function cooperatively to further improve the ionic conductivity , .…”

Three-dimensional multiphysics coupling numerical simulation of a proton conductor solid oxide fuel cell based on multi-defect transport

“…19 Conductivity tests and transport number studies have shown that mixed conduction of protons, oxygen ions, and electron holes occurs under high oxygen partial pressure and high temperature conditions. 19–22 The variation in conductivity with oxygen partial pressure can be explained using the reaction for electron hole formation (h˙). The formation reaction of h˙ is:…”

Suppression of Leakage Current in Proton-Conducting BaZr0.8Y0.2O3−δ Electrolyte by Forming Hole-Blocking Layer

“…1 However, non-negligible charge-carriers other than protons are known to exist in typical proton-conducting solid electrolytes at relatively high temperatures. [14][15][16][17][18][19][20][21][22][23] Figure 1 schematically illustrates the charge-carriers in the proton-conducting solid electrolytes. The existence of the partial conductions of oxide-ions, holes and electrons will decrease the protonic transport number and the electrical efficiency.…”

“…Especially, the presence of conduction of holes in the electrolyte will cause internal leakage current that would result in serious decrease of electrical efficiency. 23 Choudhury and Patterson established a theoretical treatment to evaluate the leakage current. 24,25 In this study, the leakage current in bi-layered electrolyte with a base electrolyte layer consisting of Y 2 O 3 -doped BaZrO 3 coated with a hole-blocking-layer have been investigated.…”