| 摘要: | La2NiO4的層狀Ruddlesden-Popper（RP）結構具有比其他固態氧化物燃料電池（SOFC）的陰極材料優異之電化學活性。本研究的主要目的是探討La2NiO4陰極材料摻雜Mg的多層Ruddlesden-Popper（RP）結構，該材料是通過甘氨酸-硝酸鹽燃燒法（GNP）製備。其化學式為〖La〗_(n+1) 〖Ni〗_(n(1-x)) 〖Mg〗_nx O_((3n+1)-δ)，x為摻雜濃度，n為RP結構層數。本研究主要分為三個階段。第一階段是探討在La2NiO4中摻雜Mg的適當濃度，研究了四個Mg含量分別為x = 0、0.02、0.03和0.04，其縮寫為LNO，LN1M2，LN1M3和LN1M4。在這些樣品中，由於LN1M3（3％Mg摻雜之La2NiO4）具有高的非化學計量氧空位（δ）、高電導率（〜200 S / cm）和出色的電化學反應性，被認為是SOFC中最好的陰極材料。在第二階段中，製備較LN1M3多層之RP結構(n = 2&3)，如：LN3M3，其棒狀顆粒的框架可有效的提升電導率(即σ〜800 S / cm)，並降低極化電阻（Rp為1.41Ωcm2）。在最後階段，將樣品LN3M3絲網印刷在不同的SOFC鈕扣電池上，以研究其陰極性能，這些鈕扣電池具有不同的支撐類型（電解質支撐、陽極支撐）以及不同的電解質材料（BaCe0.6Zr0.2Y0.2O3，BCZY、(ZrO2)0.92(Y2O3)0.08，YSZ）， 由I-V測試之結果得到了LN3M3陰極在YSZ陽極支撐電池中有最佳之功率密度為：Pmax 205 mW / cm2，並經由電化學阻抗分析（EIS），模擬等效電路得到極化電阻為：Rp 0.12Ωcm2。;Layered Ruddlesden-Popper (RP) structure such as La2NiO4 has superior electrochemical activity than other cathode material for Solid Oxide Fuel Cell (SOFC). The primary purpose of this work is to explore new cathode material with higher-order Ruddlesden-Popper (RP) structure Mg-doped La2NiO4 material, which produces via Glycine-Nitrate Process (GNP). The general chemistry formula is 〖La〗_(n+1) 〖Ni〗_(n(1-x)) 〖Mg〗_nx O_((3n+1)-δ) with x is doping concentration and n as the number of RP structure layers. Three phases were taken to achieve the purpose of this work. The first phase is to explore the appropriate concentration of Mg-doped in La2NiO4. Four samples with magnesium contents varying in x= 0,0.02,0.03, and 0.04, abbreviated as LNO, LN1M2, LN1M3, and LN1M4, respectively, were investigated. Among the specimens, LN1M3 (i.e., 3% Mg-doped La2NiO4) was found the best cathode material used in SOFC, due to high nonstoichiometric oxygen-vacancy (δ), high electrical conductivity (~200 S/cm) and excellent electrochemical reactivity. In the second phase, higher-order (n=2 &3) RP structure such as LN3M3 based on LN1M3 was formed to indicate a frame of rod-like particles to reveal good electrical conductivity (i.e., σ ~ 800 S/cm) and low polarization resistance (Rp at 1.41 Ωcm2). In the final phase, specimen LN3M3 was screen-printed on different SOFC button cells to study their cathodic performance. These button cells were different in configuration (one supported by electrolyte and another supported by anode) and distinct in electrolytes (one is BaCe0.6Zr0.2Y0.2O3, BCZY, and the other is (ZrO2)0.92(Y2O3)0.08, YSZ). The results of I-V testing demonstrate different maximum power density. LN3M3 in YSZ anode-supported cell achieved the best power density Pmax 205 mW/cm2 and polarization resistance Rp 0.12 Ωcm2. The simulation of equivalent circuits of the electrochemical impedance spectroscopy (EIS) is useful to understand the difference in power density. |
