Fabrication of dense and defect-free diffusion barrier layer via constrained sintering for solid oxide fuel cells

Synthesis and structural evolution of partially and fully stabilized ZrO2 from a versatile method aided by microwave power

“…Tetragonal zirconia under elevated temperatures tends to the exhibit a large volume change (3-5%) along cooling process to the monoclinic phase around to 970°C [1,4]. Therefore, one of the major challenges in the use of ZrO 2 lies in the difficulty in to obtain a stable crystalline structure, i.e., fully stabilized zirconia (FSZ) [1], mainly, in the tetragonal and cubic phases which are more valuable for technological applications [6][7][8][9][10][11][12][13][14][15]. However, zirconia stabilized can be obtained by the incorporation of stabilizing agents such as divalent cations (Mg 2+ [16], Ca 2+ [17]) and/or trivalent rare earth cations (Y 3+ [12,18,19], Gd 3+ [20][21][22], Eu 3+ [9,23,24], Er 3+ [8,25] and Tb 3+ [26,27].…”

Crack‐free cathode of intermediate‐temperature solid oxide fuel cells via electrospray deposition

“…Among them, it is essential to establish structurally durable cathode fabrication conditions because the microscale cracks on the cathode surface and the delamination at the interface between electrolyte and cathode increase the polarization resistance and eventually degrades the performance and stability of the cell. [23][24][25] Therefore, we focused on the T dep of the ESD process, directly related to the structural difference of the cathode according to the thermal properties of the polymer dispersant. In Figure 1, the heat flow of polymer dispersant, PVP, as a function of temperature was measured by DSC analysis.…”

“…Thus, in this step, cracks and delamination occur at the cathode due to the thermal mismatch between the deposited membrane and the pre-sintered substrate. 23,24 The aforementioned defects lead to a decrease in the active ORR sites and eventually degrade the electrochemical performance of SOFCs. 25 Consequently, the fabrication of defect-free cathode is important for cell operation.…”

“…Moreover, as shown in our previous report, 14 the amount of polymer dispersant in the cathode slurry should be as high as ceramic powder. Thus, in this step, cracks and delamination occur at the cathode due to the thermal mismatch between the deposited membrane and the pre‐sintered substrate 23,24 . The aforementioned defects lead to a decrease in the active ORR sites and eventually degrade the electrochemical performance of SOFCs 25 .…”

Image analysis of the porous yttria-stabilized zirconia (YSZ) structure for a lanthanum ferrite-impregnated solid oxide fuel cell (SOFC) electrode

“…The high sintering temperatures (above 1300 o C) required of densification of YSZ, preclude the use of many potential La-based perovskites because of the reaction with YSZ forming insulating La2Zr2O7, or the lack of chemical/physical stability at the process temperatures. To avoid exposure of these more reactive materials to the high-temperature sintering process, one strategy is to apply a diffusion barrier layer to avoid the reaction at high temperature, [2] but the impregnation of perovskites materials into a porous well-sintered YSZ scaffold can also used to fabricate the composite electrode at low temperatures [3,4]. For example, strontium-doped LaFeO3 (LSF) or (La, Sr)(Co,Fe)O3 (LSCF) can be used to make a high-performance cathode at intermediate temperatures between 600 o C to 800 o C with the mixed ionic and electronic conductivity (MIEC) in this material leading to high electrochemical performance [5][6][7][8][9][10][11].…”