Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Shanmugam, Sangaraju | - |
| dc.contributor.author | Abdul Aziz | - |
| dc.date.accessioned | 2017-05-10T08:53:29Z | - |
| dc.date.available | 2020-02-28T09:21:29Z | - |
| dc.date.issued | 2017 | - |
| dc.identifier.uri | http://dgist.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002323613 | en_US |
| dc.identifier.uri | http://hdl.handle.net/20.500.11750/1493 | - |
| dc.description.abstract | The ultra-high proton/vanadium ion selective composite membranes for vanadium redox flow battery (VRB) consisting of ZrO2 nanotubes (ZrNT) with perfluorosulfonic acid (Nafion) and polyoxometalate coupled with a graphene oxide-sulfonated poly(arylene ether ketone) (SPAEK) were designed and fabricated. The main goal of introducing ZrNT and PW-mGO fillers in Nafion and SPAEK membrane are to provide high proton conductivity of the composite membrane as well as to partially block the porous structure of Nafion and SPAEK pristine membranes to reduce the vanadium ion permeability by tortuous pathway effect. The incorporation of zirconium oxide nanotubes in the Nafion matrix exhibited high proton conductivity (95.2 mS cm-1), low vanadiumion permeability (3.2 × 10-9 cm2 min-1) and superior ion selectivity (2.95 × 107 S min cm-3). Similarly, the superior proton conductivity of SPAEK-PW mGO composite membrane exhibits 20-times lower vanadium ion crossover than a pristine Nafion membrane. The fabricated composite membranes, Nafion-ZrNT and SPAEK/PW-mGO were used as an electrolyte membrane for VRB showed low self-discharge rate (open circuit voltage was maintained above 1.3 V after a period of 330, 441 h, respectively) relative to a pristine Nafion membrane (29 h). After 100th charge-discharge cycle, the capacity retention for Nafion-ZrNT and SPAEK/PW-mGO composite membrane exhibits 66 and 78%, respectively, which are much better compared with a Nafion membrane (38%). The high performance of composite membranes can be more obviously observed in the coulombic efficiency, voltage efficiency and energy efficiency of the VRB with Nafion-ZrNT and SPAEK/PW-mGO composite membranes compared with a Nafion membrane at a 40 mA cm-2 current density. The detailed overview are reported in results and discussion part. The improved performance is attributed to the superior proton conductivity, low vanadium permeability and strong chemical stability of Nafion-ZrNT and SPAEK/PW-mGO composite membranes. ⓒ 2017 DGIST |
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| dc.description.tableofcontents | I. INTRODUCTION 1-- 1.1 Theoretical background 1-- 1.2 The fundamental of VRFB 2-- 1.3 Problem description and current understanding 3-- 1.4 The development of VRFB technique 5-- 1.4.1 Carbon electrode and its improvement 5-- 1.4.2 Membrane development 5-- 1.4.2.1 Chemical stability 6-- 1.4.2.2 Water transport 7-- 1.4.2.3 Vanadium ion crossover 8-- 1.4.3 Membrane materials for VRFB system 10-- 1.4.3.1 Nafion/filler hybrid membranes 10-- 1.4.3.2 Nafion modification with ion exchange polymer 12-- 1.4.3.3 Non-ion exchange polymer modification 13-- 1.4.3.4 Hydrocarbon polymer 14-- 1.4.3.5 Anion exchange membranes 15-- 1.4.4 Effort for electrolyte improvement 17-- 1.5 Motivation and goal of this dissertation 18-- 1.5.1 Nafion-ZrO2 nanotube composite membrane 19-- 1.5.2 SPAEK/ Polyoxometalate-modified graphene oxide composite membrane 20-- II. EEPERIMENTAL SECTTION 22-- 2.1 Nafion-ZrO2 nanotube composite membrane 22-- 2.1.1 Materials 22-- 2.1.2 Preparation of ZrO2 nanotubes 22-- 2.1.3 Preparation of Nafion-ZrO2 nanotubes composite membrane 22-- 2.2 SPAEK/ Polyoxometalate-modified graphene oxide composite membrane 23-- 2.2.1 Materials 23-- 2.2.2 Synthesis of hydrophilic oligomer 23-- 2.2.3 Synthesis of hydrophobic oligomer 24-- 2.2.4 Synthesis of block copolymer (SPAEK) 24-- 2.2.5 Preparation of graphene oxide 25-- 2.2.6 Preparation of reduced graphene oxide 25-- 2.2.7 Preparation of modified graphene oxide 25-- 2.2.8 Preparation of PW-mGO material 26-- 2.2.9 Preparation of SPAEK/PW-mGO composite membrane 26-- 2.3 Characterization 26-- 2.3.1 Field-emission scanning electron microscope (SEM) 26-- 2.3.2 Field-emission transmission electron microscope (TEM) 26-- 2.3.3 X-ray diffraction (XRD) 27-- 2.3.4 Water uptake, Swelling degree and Ion exchange capacity (IEC) 27-- 2.3.5 Proton conductivity 27-- 2.3.6 Oxidative stability 28-- 2.3.7 Thermal stability 28-- 2.3.8 Measurements of VO2+ permeability and ion selectivity 28-- 2.3.9 Measurements of vanadium flow battery performance 29-- III RESULTS AND DISCUSSION 32-- 3.1 Nafion-ZrO2 nanotube composite membrane 32-- 3.1.1 Characterization of ZrO2 nanotube 32-- 3.1.2 Characterization of Nafion-ZrO2 nanotube composite membrane 34-- 3.1.3 VO2+ permeability and ion selectivity 41-- 3.1.4 Vanadium flow battery performance 43-- 3.2 SPAEK/ Polyoxometalate-modified graphene oxide composite membrane 52-- 3.2.1 Characterization of composite membrane 52-- 3.2.2 VO2+ permeability and ion selectivity 55-- 3.2.3 Vanadium flow battery performance 57-- IV CONCLUSIONS 68-- V REFERENCES 69 |
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| dc.format.extent | 85 | - |
| dc.language | eng | - |
| dc.publisher | DGIST | - |
| dc.subject | Vanadium redox flow battery | - |
| dc.subject | composite membrane | - |
| dc.subject | Nafion | - |
| dc.subject | vanadium ion crossover | - |
| dc.subject | ion selectivity | - |
| dc.subject | 바나듐 레독스 플로우 배터리 | - |
| dc.subject | 복합막 | - |
| dc.subject | 나피온 | - |
| dc.subject | 바나듐 이온 크로스오버 | - |
| dc.title | Development of ultra-high ion selective composite membranes for all vanadium redox flow battery | - |
| dc.title.alternative | 바나듐 레독스 플로우 배터리 운용을 위한 뛰어난 이온 선택성을 지닌 복합막 개발 | - |
| dc.type | Thesis | - |
| dc.identifier.doi | 10.22677/THESIS.2323613 | - |
| dc.description.alternativeAbstract | 본 학위논문에서는 바나듐 레독스 플로우 배터리 (VRB)를 위한 매우 높은 양성자/바나듐 이온 선택성을 지닌 ZrO2 나노튜브 (ZrNT) 가 섞인 나피온 복합막과 비 나피온계 폴리 옥소메탈레이트-그래핀 옥사이드-아로마성 술폰화된 폴리 아릴렌 에테르 케톤 (Sulfonated poly (arylene ether ketone) (SPAEK) 복합막를 제작하였다. ZrNT와 PW-mGO를 도입한 나피온과 SPAEK 막의 주 목적은 복합막의 높은 이온 전도도를 얻고, 다공성 구조의 순수 나피온와 SPAEK막의 공극을 부분적으로 막아 구불구불한 경로 효과를 통해 낮은 바나듐 이온 투과도를 얻기 위함이다. ZrNT가 도입된 나피온막은 높은 이온전도도 (95.2mS cm-1) 를 보이며 낮은 바나듐 이온 투과도 (3.2 × 10-9 cm2 min-1) 를 보이고, 뛰어난 이온 선택성 (2.95 × 107 S min cm-3) 을 보여준다. 유사하게, SPAEK-PW mGO 복합막은 순수 나피온막과 비교하였을 시 20배의 낮은 바나듐 이온 크로스오버를 보였다. 본 연구에서 제작된Nafion-ZrNT 와 SPAEK/PW-mGO 복합막이 적용된 VRB는 순수 나피온 막(개방전압은 29시간 동안 1.3 V 이상 유지됨) 과 비교하였을 시, 낮은 자가 방전비 (개방전압은 330, 441시간 후에도 각각 1.3 V 이상을 유지하였음)을 보였다. 100회의 충방전 사이클 후, Nafion-ZrNT 와 SPAEK/PW-mGO 복합막의 용량보유력은 각각 66% 와 78% 이었으며, 이 값은 순수 나피온 막 (38%) 에 비해 훨씬 큰 값이다. 이러한 복합막의 높은 성능, 즉 높은 쿨롱 효율, 전압 효율, 및 에너지 효율은 40 mA cm-2 전류 밀도에서 연구를 진행하였을 시 확연하게 관찰이 가능하였다. 자세한 연구결과는 본 학위논문의 결과 및 토론 파트에 논의하였다. 향상된 성능은 Nafion-ZrNT 와SPAEK/PW-mGO 복합막의 뛰어난 이온 전도도, 낮은 바나듐 투과도 및 강한 화학적 안정성 특성에 기인한다. ⓒ 2017 DGIST | - |
| dc.description.degree | Master | - |
| dc.contributor.department | Energy Systems Engineering | - |
| dc.contributor.coadvisor | Kim, Jae Hyeon | - |
| dc.date.awarded | 2017. 2 | - |
| dc.publisher.location | Daegu | - |
| dc.description.database | dCollection | - |
| dc.date.accepted | 2017-01-18 | - |
| dc.contributor.alternativeDepartment | 대학원 에너지시스템공학전공 | - |
| dc.contributor.affiliatedAuthor | Abdul Aziz | - |
| dc.contributor.affiliatedAuthor | Shanmugam, Sangaraju | - |
| dc.contributor.affiliatedAuthor | Kim, Jae Hyeon | - |
| dc.contributor.alternativeName | 무하마드 압둘 아지즈 | - |
| dc.contributor.alternativeName | 상가라쥬샨무감 | - |
| dc.contributor.alternativeName | 김재현 | - |
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