梯度Cu-CeO2-Ni-YSZ复合阳极直接甲烷SOFC的制备与性能

采用三层共压-共烧结法, 并涂覆La_0.8Sr_0.2MnO₃ (LSM)阴极, 制备了梯度Ni-YSZ阳极结构的固体氧化物燃料电池(SOFC)(大孔Ni-YSZ|微孔Ni-YSZ|YSZ|LSM) (YSZ: Y₂O₃稳定的ZrO₂; LSM: Sr 掺杂的LaMnO₃).通过浸渍法在大孔Ni-YSZ 基底中沉积占总重量约1%的Cu-CeO₂抗积碳催化剂, 形成梯度Cu-CeO₂-Ni-YSZ复合阳极. 分别以CH₄和H₂为燃料, 空气为氧化剂, 测定了构造的SOFC输出电性能和长期稳定性. 结果表明,三层共压-共烧结法制备的梯度阳极SOFC, 层间结合紧密无缺陷, 阳极梯度孔结构明显, YSZ膜致密无缺陷.在850℃下操作, 以梯度Ni-YSZ 阳极制备的SOFC, 燃料由H₂切换为甲烷时, 最大功率密度由284 mW·cm^-2下降到143 mW·cm^-2; 而以Cu-CeO₂-Ni-YSZ 复合阳极构造的SOFC出现相反趋势, H₂切换为甲烷后最大输出由176 mW·cm^-2增加到196 mW·cm^-2. 在250 mA·cm^-2负荷下, 梯度Ni-YSZ阳极支撑的直接甲烷SOFC仅稳定运转10 h 便出现明显衰减, 阳极中积碳严重; 但Cu-CeO₂-Ni-YSZ 复合阳极支撑SOFC连续运转50 h, 输出电压与输出功率密度基本不变, 电镜观察不到积碳.

Preparation and Properties of Direct-Methane Solid Oxide Fuel Cell Based on a Graded Cu-CeO2-Ni-YSZ Composite Anode

A graded anode-supported solid oxide fuel cell (SOFC) with the structure porous Ni-yttria stabilized zirconia (Ni-YSZ)|microporous Ni-YSZ|YSZ|La_0.8Sr_0.2MnO₃ (LSM) was fabricated by a trilayer co-pressing-sintering method, and coating with an LSM cathode. Cu-CeO₂ was impregnated into the porous Ni-YSZ layer using nitrate/glycol precursors to act as an anti-carbon catalyst to fabricate a graded Cu-CeO₂-NiO-YSZ composite anode. The current-voltage (I-V), current-power (I-P), and long-term stability of the SOFC were tested using CH₄ or H₂ as fuels and air as an oxidant. The results show that the co-pressing-sintering layers possess a gradient pore structure with defect-free combination. The power density of SOFC supported by a graded Ni-YSZ anode is 284 mW·cm^-2, operated at 850℃ using H₂ as a fuel, but decreases to 143 mW·cm^-2 when the fuel is changed to CH₄. In contrast, the cell supported by a Cu-CeO₂-Ni-YSZ anode show the reverse behavior, increasing from 176 to 196 mW·cm^-2 when the fuel is changed from H₂ to CH₄ at 850℃. Under a 250 mA·cm^-2 load using CH₄ as the fuel, the output of the cell with a graded Ni-YSZ anode fluctuats and the cell is blocked after 10 h. At this point, carbon particles or fibers are observed in the anode layer by scanning electron microscopy (SEM). Conversely, the cell with a Cu-CeO₂-Ni-YSZ anode shows stable power output for 50 h or longer, and no carbon deposition was observed inside the anode.