纳米NiO-YSZ复合粉体原位合成及电极微结构修饰

采用氨水沉淀原位合成法制备了NiO-YSZ(Y_2O_3稳定的ZrO_2)复合粉体,通过XRD、FESEM研究了溶液pH值对粉体性能的影响,并用干压法和丝网印刷法将氢电极分为支撑层(500 μm)、过渡层(20 μm)和功能层(10 μm)三层进行梯度化制备,采用YSZ/SDC双层电解质,通过共烧结技术将SDC(Sc掺杂CeO_2)(6 μm)作为YSZ(4 μm)电解质和Ba_0.5Sr_0.5Co_0.8Fe_0.2O_(3-δ)(BSCF,20 ìm)氧电极的隔离层.结果表明,合成NiO-YSZ复合粉体的最佳pH值为8.5,粉体呈泡沫状团聚,NiO的平均晶粒粒径为13 nm,产率为94.5%.850 ℃时制备的单体SOEC在70%、80%和90% 3种水蒸气含量的氢电极气氛下,电解池在1.5 V的产氢速率分别为266、381和558 N·mL/cm~2·h.在850 ℃、90%水蒸气含量的氢电极气氛下,以0.33 A/cm~2恒流电解1 h前、后的电解电压分别为1.09和1.16 V,电解池具备较好的稳定性.

Preparation of Nanosized NiO-YSZ Composite Powders by Situ-Precipitation Method

Nickel oxide and yttria-stabilized zirconia (NiO-YSZ) composite powders were synthesized by situ-precipitation method to prepare high performance hydrogen electrode with long-term durability operating in the Solid Oxide Electrolysis Cells (SOEC) mode. The products were characterized by XRD and FESEM, and the effect of pH on the average crystallite size and yield of the NiO was studied. A single SOEC with 500 μm NiO-YSZ support, 20 μm NiO-YSZ interlayer, 10 μm NiO-YSZ hydrogen electrode, 4 μm YSZ electrolyte, 6 μm SDC electrolyte and 20 μm BSCF oxygen electrode was prepared for performance tests. The results showed that the NiO-YSZ composite powders agglomerate to form spongy structure and the optimized pH of NiO-YSZ synthesized was 8.5. The related NiO average crystallite size is 13 nm and the yield is 94.5%. When the steam content in the input stream is 70%, 80% and 90% at 850 ℃, the hydrogen production rate of the single SOEC is 266, 381 and 558 N·mL/cm~2·h, respectively. The electrolytic voltage changed from 1.09 to 1.16 V at 1 h before and after the electrolysis with the current density of 0.33 A/cm~2 at 850 ℃ and 90% H_2O + 10% H_2 as inlet gas, which showed the prepared SOEC had excellent durability.