{"created":"2021-03-01T06:14:38.667112+00:00","id":7959,"links":{},"metadata":{"_buckets":{"deposit":"71afad71-d4af-4e8e-9815-f13d36c09340"},"_deposit":{"id":"7959","owners":[],"pid":{"revision_id":0,"type":"depid","value":"7959"},"status":"published"},"_oai":{"id":"oai:nagoya.repo.nii.ac.jp:00007959","sets":["488:641:642"]},"author_link":["22702","22703"],"item_12_alternative_title_19":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"(プロトン導電体Sn_0.9In_0.1P_2O_7 を電解質に用いた中温作動燃料電池)","subitem_alternative_title_language":"ja"}]},"item_12_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2008-03-25","bibliographicIssueDateType":"Issued"}}]},"item_12_date_granted_64":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2008-03-25"}]},"item_12_degree_grantor_62":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"名古屋大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Nagoya University"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"13901","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_12_degree_name_61":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(工学)","subitem_degreename_language":"ja"}]},"item_12_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Proton exchange membrane fuel cells (PEMFCs) have received increasing attention for transportation and residential applications because of their high efficiencies and environmentally-friendly characteristics. However, there still remain several challenges regarding technology and materials costs for their widespread commercialization. In the PEMFCs, the electrolyte (usually Nafion) requires highly humidified conditions to achieve its sufficient proton conductivity and then gas humidifiers required increase the complexity and the cost of the fuel cell system. Current PEMFCs typically run at ~80ºC because of the working temperature limitation of the electrolyte, which causes serious CO poisoning of the anode catalyst and needs to use the expensive Pt catalysts. Such challenges can obviously be overcome by using a proton conductor functioning as the electrolyte above 100ºC under unhumidified conditions. Thus, considerable efforts have been devoted to developing such proton conductors worldwide. Recently, Hibino et al. found an anhydrous proton conductor, 10 mol% In^3+-doped SnP_2O_7 (Sn_0.9In_0.1P_2O_7), showing high proton conductivities at intermediate temperatures between 150 and 350ºC under unhumidified conditions. This study aimed to demonstrate the feasibility of intermediate-temperature fuel cells using Sn_0.9In_0.1P_2O_7 as an electrolyte and to prove desirable advantages in the intermediate-temperature fuel cells over current PEMFCs. The proton conductivity of Sn_0.9In_0.1P_2O_7 and the proton conduction mechanism in the Sn_0.9In_0.1P_2O_7 were reported in Chapter 2. The proton conductivity of Sn_0.9In_0.1P_2O_7 was more than 10^{-1} S cm^{-1} between 125 and 350ºC in unhumidified conditions, where a conductivity value of 1.95 x 10^{-1} S cm^{-1 }was achieved at 250ºC. Sn_0.9In_0.1P_2O_7 had proton transport numbers of ~ 1 and exhibited a large H/D isotope effect on conductivity. These results indicate that the charge carriers of Sn_0.9In_0.1P_2O_7 were not H_3O^+ ions, but protons which migrated between the lattice oxide ions according to a hopping mechanism. Performance of a fuel cell using Sn_0.9In_0.1P_2O_7 as an electrolyte was investigated in the temperature range of 150-300ºC under unhumidified conditions in Chapter 3. In a H_2/air fuel cell with Pt/C anode and cathodes, open circuit voltages (OCVs) were about 920 mV and the peak power density reached 152 mW cm^{-2 }and 264 mW cm^{-2} at 250ºC using the electrolytes with 1.00 and 0.35 mm thickness, respectively. Furthermore, the fuel cells showed excellent tolerance toward 10% CO and good thermal stability under unhumidified conditions. One of the additional advantages in the intermediate-temperature fuel cell is the use of Pt-free electrodes. The development of alternative catalysts to replace Pt is attempted for anode and cathodes in the intermediate-temperature fuel cell in Chapter 4. Carbon-supported molybdenum carbide - zirconia (Mo_2C-ZrO_2/C) showed a high anode performance toward the hydrogen oxidation reduction. The performance of a fuel cell using Mo_2C-ZrO_2/C as an anode was almost comparable to that using a Pt/C as an anode at 250ºC or higher. Carbon-supported zirconia (ZrO_2/C) showed a high cathode performance. The performance of a fuel cell using the ZrO_2/C cathode was about one-third of that using the Pt/C cathode at 250ºC or higher. The other additional advantage in the intermediate-temperature fuel cell is the direct use of alternative fuels to replace hydrogen. Direct DME fuel cells (DDMFCs) and direct hydrocarbon fuel cells at the intermediate temperatures between 150 and 300ºC are investigated in Chapter 5. In these fuel cells, all the DME and hydrocarbons were electrochemically converted into CO_2 along with their direct oxidation at the intermediate temperatures and reasonable cell performances were achieved. Sn_0.9In_0.1P_2O_7 electrolytes may be required to be a thin, dense, and flexible electrolyte membrane for their practical applications. Sn_0.9In_0.1P_2O_7 - based organic/inorganic composite membranes were developed in Chapter 6. The composition of the composite membrane was determined to be 90 wt.% Sn_0.9In_0.1P_2O_7 for achieving both the high proton conductivity and flexibility of the composite membranes. Fuel cell tests verified that the OCV was maintained at a constant value of approximately 970 mV regardless of the electrolyte thickness (60-200 μm) and the peak power densities achieved with unhumidified H_2 and air were 197 mW cm^{-2} at 150ºC, and 226 mW cm^{-2 }at 200ºC. Furthermore, a membrane electrode assembly (MEA) fabrication technique offered the potential for enhancing the fuel cell performance. The intermediate-temperature fuel cell using the Sn_0.9In_0.1P_2O_7 electrolyte exhibited a more stable performance at low relative humidities and high CO concentrations compared to current PEMFCs. Furthermore, it was demonstrated that the present fuel cells have additional advantages such as the use of non-Pt electrodes and the direct use of alternative fuels. The preferred advantages in the intermediate-temperature fuel cell would improve the overall fuel cell efficiency and make fuel cell systems significantly simpler and more economic. ","subitem_description_language":"en","subitem_description_type":"Abstract"},{"subitem_description":"固体高分子形燃料電池（PEMFC）は自動車・家庭用エネルギー変換機として注目されているが、その実用化のためには未だ様々な課題が残っている。通常使用されている電解質であるNafion は含水状態でのみ高いプロトン導電率を示すために過度な加湿が必要であり、それによって必要とされる加湿装置は燃料電池システムをより複雑にさせ、そのコストを高める。また、作動温度が80℃以下であるためアノード触媒が燃料中のCO によって被毒され、更に高価のPt 電極触媒を使用しなければいけない。これらの課題は100℃以上、無加湿条件下で作動できるプロトン導電体を使用することで解決されるはずである。それ故、そのようなプロトン導電体材料の開発は世界中で活発に行われている。最近、150℃～350℃の中温域、無加湿条件下で高いプロトン導電率を示す非含水系プロトン導電体10 mol% In^3+ドープSnP_2O_7 (Sn_0.9In_0.1P_2O_7)が日比野らによって見出された。本研究ではこの材料を電解質として使用した中温作動燃料電池の実現と、PEMFC に対する中温作動燃料電池の利点の実証を目的とした。第2 章においてはSn_0.9In_0.1P_2O_7 のプロトン導電率とプロトン伝導機構を報告した。Sn_0.9In_0.1P_2O_7 は125℃～350℃、無加湿条件下で10^{-1 }S cm^{-1 }以上のプロトン導電率を示し、250℃では1.95×10^{-1} S cm^{-1} であった。また、Sn_0.9In_0.1P_2O_7 はほぼ1 に近いプロトン輸率を持ち、導電率において高いH/D 同位体効果を示した。この結果は、Sn_0.9In_0.1P_2O_7 の電荷担体がH_3O^+イオンではなくプロトン(H+^)であり、そのプロトンは格子酸素イオン間をホッピング機構によって移動することを示している。第3 章ではSn_0.9In_0.1P_2O_7 を電解質として使用し、150-300ºC の温度範囲・無加湿条件下で燃料電池の性能を評価した。Pt/C を電極に使用した水素/空気燃料電池において、電解質の膜厚を1.00 mm と0.35 mm にした場合、250ºC で、それぞれ152 mW cm^{-2}と264 mW cm^{-2 }の最大出力密度が得られた。更に、この燃料電池は10%CO 含有燃料に対しても優れた耐性を示し、無加湿条件下でも熱的に安定であった。中温作動燃料電池において、その他の利点としてPt フリー電極の使用がある。第4章では中温作動燃料電池のアノードとカソードにおけるPt 代替触媒の開発を試みた。水素酸化反応においてはモリブデンカーバイド－ ジルコニア担持カーボン(Mo_2C-ZrO_2/C)が高いアノード性能を示した。作動温度250℃以上において、Mo_2C-ZrO_2/C をアノードに使用した燃料電池の性能はPt/C をアノードに使用した場合の性能に匹敵した。また、ジルコニア担持カーボン(ZrO_2/C)は高いカソード性能を示した。作動温度250℃以上において、ZrO_2/C をカソードに使用した燃料電池の性能はPt/C をカソードに使用した場合の性能の約1/3 程度であった。中温作動燃料電池の利点としてもう一つは水素の代替燃料の使用である。第5 章では150～300℃の中温域におけるダイレクトジメチルエーテル燃料電池(DDMEFC)とダイレクト炭化水素燃料電池を調べた。これらの燃料電池においてDME と炭化水素燃料は、電気化学的直接酸化反応によってCO2 に変換され、妥当な電池性能が得られた。Sn_0.9In_0.1P_2O_7 電解質はその実用化のために、薄くて緻密性、柔軟性ある電解質膜にする必要がある。第6 章ではSn_0.9In_0.1P_2O_7 を含む有機/無機コンポジット膜の開発を行った。コンポジット膜の高いプロトン導電率と柔軟性の両方を考慮して、膜中のSn_0.9In_0.1P_2O_7 量は90wt%とした。燃料電池を構成したところ、OCV は電解質の膜厚（60~200μm）に依存せず約970 mV で維持され、最大出力密度は150℃で197 mW cm^{-2}、200℃で226 mW cm^{-2} であった。更に、電解質膜電極複合(MEA)の作製により燃料電池性能は向上した。以上のようにSn_0.9In_0.1P_2O_7 電解質を使用した中温作動燃料電池はPEMFC に比べ、低い相対湿度と高いCO 濃度での安定した性能を示した。また、本燃料電池はPt フリー電極の使用や代替燃料の直接使用などの更なる利点を持つことが実証された。これらの利点により中温作動燃料電池は燃料電池総合効率の向上とそのシステムの大幅な簡略化・低コスト化が期待できる。","subitem_description_language":"ja","subitem_description_type":"Abstract"}]},"item_12_description_5":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"名古屋大学博士学位論文 学位の種類:博士（工学）（課程）","subitem_description_language":"ja","subitem_description_type":"Other"}]},"item_12_dissertation_number_65":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第7815号"}]},"item_12_identifier_60":{"attribute_name":"URI","attribute_value_mlt":[{"subitem_identifier_type":"HDL","subitem_identifier_uri":"http://hdl.handle.net/2237/9691"}]},"item_12_select_15":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"publisher"}]},"item_12_text_14":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_text_value":"application/pdf"}]},"item_12_text_63":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2007"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"HEO, Pilwon","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"22702","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"許, 弼源","creatorNameLang":"ja"}],"nameIdentifiers":[{"nameIdentifier":"22703","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-02-19"}],"displaytype":"detail","filename":"k7815_thesis.pdf","filesize":[{"value":"3.3 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"k7815_thesis.pdf","objectType":"fulltext","url":"https://nagoya.repo.nii.ac.jp/record/7959/files/k7815_thesis.pdf"},"version_id":"3f25410c-f959-4eb0-ba34-a554d800630d"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Intermediate-Temperature Fuel Cells Using a Proton-Conducting Sn_0.9In_0.1P_2O_7 Electrolyte","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Intermediate-Temperature Fuel Cells Using a Proton-Conducting Sn_0.9In_0.1P_2O_7 Electrolyte","subitem_title_language":"en"}]},"item_type_id":"12","owner":"1","path":["642"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-04-17"},"publish_date":"2008-04-17","publish_status":"0","recid":"7959","relation_version_is_last":true,"title":["Intermediate-Temperature Fuel Cells Using a Proton-Conducting Sn_0.9In_0.1P_2O_7 Electrolyte"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-01-16T03:53:29.307143+00:00"}