摻雜對LaCoO3陰極材料電性之影響

本研究是利用固態合成法製備鈣鈦礦型菱方晶結構鈷酸鑭基SOFC陰極材料，主要是利用摻雜半徑相近的離子取代LaCoO3中部分Co3+，藉以開發最佳導電率之陰極材料。本實驗將LaCo1-x-y□x□yO3–δ分別摻雜NiO、CuO及TiO2，透過固態合成法製備鈷酸鑭基陰極粉末。配合不同的摻雜劑利用不同的製程參數進行燒結，並測量其電性，期望能找出最佳成分配比及製程條件。研究結果發現，微量摻雜TiO2導致燒結緻密化溫度和重量損失過高，因此此種摻雜劑不利應用於鈷酸鑭基陰極材料。以摻雜CuO的LaCo1-xCuxO3-δ而言，當Cu摻雜含量高於20%時，則已經超過固溶限且會產生二次相(La2CuO4.05)，其結構為菱方晶，而二次相為斜方晶結構。另外在同時摻雜NiO及CuO 的LaCo0.4Ni0.6-xCuxO3-δ系統中，同時摻雜40%的Ni和20%的Cu，發現當Cu摻雜含量超過20%時則無法再固溶並產生第二相(La4Ni3O10和La2CuO4.032)。在500℃時LaCo0.4Ni0.4Cu0.2O3-δ有最高導電率1750 S•cm-1，導電模式為金屬導電。在750℃時LaCo0.8Cu0. 2O3-δ有最高導電率約1286 S•cm-1，其他組成的最高導電率亦相近，為半導體導電模式。

關鍵字

鈣鈦礦；固態氧化物燃料電池；鈷酸鑭；陰極

並列摘要

The purpose of this study was to develop perovskite-type lanthanum cobalt-based solid cathodes for SOFC (Solid Oxide Fuel Cell). In order to achieve the best conductivity of the cathode materials applications, these ceramics were doped with similar ions with larger ionic radii than that of Co3+ ion and to substitute part of the ion Co3+ in LaCoO3. Various dopants including NiO、CuO and TiO2 were added into to LaCo1-x-y□x□yO3–δ, respectively. These lanthanum cobalt-based solid cathode powders were synthesized by solid state reaction. These specimens were sintered at various temperatures and periods of time, then the conductivity of the specimens were measured. The results showed that, sintering temperature and weight loss is too high for achieve the desired densities by doping TiO2, therefore, the dopant were unfavorable used in the lanthanum cobalt-based cathode. The LaCo1-xCuxO3-δ of results showed that, solid solution been more than 20% will produce secondary phase (La2CuO4.05) by doping CuO, main structure is rhombohedral, while the secondary phase structure is orthorhombic. Another LaCo0.4Ni0.6-xCuxO3-δ of results showed that, codoping NiO and CuO by 40% of Ni with 20% of Cu, solid solution been more than 20% will produce secondary phase (La4Ni3O10 and La2CuO4.032) by doping CuO. The sample with LaCo0.4Ni0.4Cu0.2O3-δ displays the highest conductivity value that reaches 1750 S cm− 1 at 500 oC. It shows that LaCo0.4Ni0.4Cu0.2O3-δ exhibits metallic like conductivity. The LaCo0.8Cu0.2O3-δ displays the highest conductivity value that reaches 1286 S cm− 1 at 750 oC, other components of the highest electrical conductivity and exhibits semiconductor like conductivity is also similar.

並列關鍵字

perovskite ； SOFC ； solid state reaction ； cathode

參考文獻

[23] 魏珮伊，摻雜錳銅對中溫型固態氧化物燃料電池陰極材料鑭鍶鈷鐵之特性影響，國立台北科技大學資源工程研究所碩士論文，2010。

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摻雜對LaCoO3陰極材料電性之影響

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