以La0.58Sr0.4Co0.2Fe0.8O3-δ為固態氧化物燃料電池陰極材料之研究

A study of La0.58Sr0.4Co0.2Fe0.8O3-δ as solid oxide fuel cell cathode material

周建良(Chien-Liang Chou)

指導教授 ： 黃大仁

國立清華大學/工學院/化學工程學系/博士(2009年)

摘要

本研究以鈣鈦礦結構材料La0.58Sr0.4Co0.2Fe0.8O3-δ (L58SCF)為固態氧化物燃料電池之陰極。LSCF可摻雜GDC作成LSCF-GDC複合式陰極材料，其電池電性效能遠優於LSCF。
添加高還原性金屬白金、銀、銅至LSCF與LSCF-GDC陰極材料中，皆可提升電池之最大能量密度(maximum power density)，各金屬之優劣順序為「Cu＞Ag＞Pt」，並且可解釋為活性金屬對於氧氣親和力之大小，氧氣親和力越高則越容易與氧氣反應(抓取氧)，故氧氣親和力為「Cu＞Ag＞Pt」。
利用LSCF-GDC-V2O5與LSCF-GDC-Cu之陰極材料，通入2~6% NO為進體進料，maximum power density會隨著NO濃度的提高而增加，足以顯示能夠直接利用電化學反應進行還原處理NO，並利用NO來發電。
LSCF-GDC-Cu陰極材料可直接還原溫室氣體CO2進而產生CO，研究發現CO的生成速率與CO2之消耗速率一致，且通入氧氣並無發現積碳之形成。並於不同反應溫度計算出其活化能為2.72 kcal/mol.

關鍵字

固態氧化物燃料電池 ； LSCF ； 電化學還原NO ； 電化學還原CO2

並列摘要

This Study used perovskite La0.58Sr0.4Co0.2Fe0.8O3-δ (L58SCF) as cathode material for the solid oxide fuel cells (SOFCs). The mixing of gadolinia-doped ceria (GDC) with LSCF to form the LSCF－GDC composite and it can perform better than pure LSCF as the SOFC cathode.
The effects of adding Cu, Ag and Pt to LSCF and the LSCF－GDC composite all increases the maximum power density over that of pure L58SCF cathode. The cathode reduction activity has been shown to follow a trend Cu >Ag > Pt. This can be explained by the oxygen affinities of the metals, which have a trend Cu >Ag > Pt.
With 2~6% NO over the LSCF-GDC-V2O5, LSCF-GDC-Cu cathodes, the maximum power density increase with increasing NO concentration. That means direct electrochemical NO reduction can occur over those cathodes when oxygen is not present.
Using LSCF-GDC-Cu cathode to reduce CO2, we found that the CO formation rate, the CO2 conversion and the generated current density increase with increasing CO2 concentration. The CO2 conversion rate equals exactly the CO formation rate and no carbon deposition occurs. The activation energy is about 2.72 kcal/mol.

並列關鍵字

Solid oxide fuel cell ； LSCF ； Electrochemical NO reduction ； Electrochemical CO2 reduction

參考文獻

[74]黃盟欽，「直接甲烷固態氧化物燃料電池之特性研究」，國立清華大學化學工程研究所，博士論文 (2008)

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