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Fabrication and Characterization of Composite Membranes for All Vanadium Redox Flow Battery
No full textVanadium redox flow battery (VRFB), composite membrane, Nafion, vanadium ion crossover, ion selectivity, PDDA, PSSAlternative sulfonated poly(arylene ether ketone) (SPAEK)-cerium zirconium oxide nanotube (Ce2Zr2O7NT) composite (SPAEK/Ce2Zr2O7) membrane, and thin Nafion-Neodymium zirconium oxide nanotube (Nd2Zr2O7) composite (Nafion-NdZr) membranes have been fabricated. and further modification was done for Nafion-NdZr composite membrane by polycation poly (diallyldimethylammonium chloride) (PDDA) and polyanion poly (sodium styrene sulfonate) (PSS) for all vanadium redox flow batteries (VRFBs) performance. VRFB operated with SPAEK/Ce2Zr2O7 (441 h) showed low self-discharge rate than pristine SPAEK (172 h) and NRE-212 (42 h) membrane, respectively. On the other hand, Nafion-NdZr composite membrane and Nafion-NdZr(1%)/[P-S]2 composite layer membrane showed higher ion selectivity and lower vanadium ion permeability than recast Nafion and Nafion/[P-S]2 layer membranes. The ion selectivity of Nafion-NdZr(1%)/[P-S]2 composite layer membrane was found to be 6.9, 3.5, and 2.3 times higher than Recast Nafion, recast Nafion/[P-S]2 layer membrane, and Nafion-NdZr(1%) composite membrane. As a result, VRFB functionated with Nafion-NdZr(1%) composite membrane and Nafion-NdZr(1%)/[P-S]2 composite layer membrane have surpassed the performance than operated with recast Nafion, and Nafion/[P-S]2 layer membrane. Noticeably, VRFB operated with Nafion-NdZr(1%)/[P-S]2 (513.7 h) composite layer membrane were revealed to have a lower self-discharge rate than Nafion-NdZr(1%) (293.2 h), Recast Nafion/[P-S]2 (124.1 h), and recast Nafion (32.7 h) membranes, respectively. Finally, the VRFB single cell constructed with Nafion-NdZr(1%)/[P-S]2 and Nafion-NdZr(1%) membrane remarkably showed 80.1% and 73.4% capacity retention, respectively over 200 charge-discharge cycles, whereas recast Nafion exhibited 41.5% capacity retention over 100 cycle at 40 mA cm-2 current density. The structure and morphology of Ce2Zr2O7NT, Nd2Zr2O7 nanotube, SPAEK/Ce2Zr2O7, Nafion-NdZr composite membrane, and Nafion-NdZr(1%)/[P-S]2 composite layer membrane were investigated by SEM, XRD, FTIR, and AFM analysis. The quantitative analysis of Nafion-NdZr(1%) and Nafion-NdZr(1%)/[P-S]2 (before and after VRFB) were measured by EDX. Also, the XPS analysis of Nafion-NdZr(1%) and Nafion-NdZr(1%)/[P-S]2 reveal the presence of [P-S] layer. Longer cyclic performance, excellent oxidative열 안정성이 입증되었다. 전반적으로, 이 논문은 VRFB를 위한 비용 효율적이고 안정적인 분리막의 쉬운 합성 방법을 제시한다..우수한 VRFB 성능, 탁월한 전기 화학적 특성 및 개발된 분리막의 향상된 내구성은 VRFB 응용 분야에서 유망한 후보로 고려될 수 있다. 이 복합막의 주요 특징은 연료 전지, 분자 분리 및 리튬 이온 전지 재료와 같은 다른 응용 분야에서도 탐구 될 수 있다. 또한, 제조 된 나노 물질은 단일 분자를 단일 입자로 분석하여 에너지 기술로 바이오 센싱 역할 또한 기대된다.화학 안정성thermal stability further prove the durability of proposed membranes. Overall, this thesis paper reports facile synthesis route, cost effective and stable membranes for VRFB. The excellent VRFB performance, outstanding electrochemical properties, and improved durability of fabricated membranes would be considered as a promising candidate for VRFB applications. The key features of this composite membrane could be explored in other applications as well, such as fuel cell, molecular separation, and lithium-ion batteries materials. Moreover, the fabricated nanomaterials might be used to analyse single molecules to single particles for energy technology to biosensing.|나피온 대체 가능한 블록공중합체 sulfonated poly(arylene ether ketone) (SPAEK)에 Ce2Zr2O7이 도입된 SPAEK/ Ce2Zr2O7 복합막과 얇은 나피온 네오디뮴 지르코늄 산화물 나노튜브 (Nd2Zr2O7) 나피온 (Nafion-NdZr) 복합막을 제조했다. 모든 바나듐 산화 환원 유동 배터리 (VRFB) 성능을 위해 polycation poly (diallyldimethylammonium chloride) 및 polyanion poly (sodium styrene sulfonate) (PSS)을 이용해 Nafion-NdZr 복합막을 더 개선하였다. SPAEK/Ce2Zr2O7은441 시간 동안 VRFB를 작동하였을 때, 기존의SPAEK 전해질막 (172 시간)과 및 NRE-212 전해질 막 (42 시간)에 비해 낮은 자체 방전율을 보였다.반면에 Nafion-NdZr(1%) 복합막과 Nafion-NdZr(1%)/[P-S]2 복합막은 무기물 뿐만 아니라 레이어 코팅이 이루어지지 않은 순수한 Nafion 과 Nafion/[P-S]2 막보다 높은 이온 선택성과 낮은 바나듐 이온 투과성을 보였다. Nafion-NdZr(1%)/[P-S]2 복합막의 이온 선택도는 recast Nafion, Nafion/[P-S]2 막, Nafion-NdZr보다 6.9 배, 3.5 배, 2.3 배 높은 것으로 나타났다. 결과적으로 Nafion-NdZr(1%) 복합막과 Nafion-NdZr(1%)/[P-S]2 복합막으로 VRFB의 성능이 recast Nafion 및 Nafion/[P-S]2 막의 성능보다 뛰어났습니다. VRFB작동 아래, NdZr(1%)/[P-S]2은531.7시간동안 작동되었으며, Nafion-NdZr (1%)은 293.2 시간, Recast Nafion / [PS] 2는 124.1 시간, 그리고 Nafion 막은 32.7 시간 작동이 가능하였다. Nafion-NdZr (1 %) / [PS] 2와 Nafion-NdZr (1%) 막으로 구성된 VRFB 단일 셀은 200 회의 충 방전 사이클 동안 각각 80.1 %와 73.4 %의 용량 유지율을 보여 주었지만, SPAEK / Ce2Zr2O7, Nafion-NdZr 복합 막 및 NdZr(1%)/[P-S]2막은40 mA cm-2 전류 밀도에서 100 싸이클에 걸쳐 41.5 % 유지됨을SEM, XRD, FTIR 및 AFM 분석을 통해 조사 하였다. VRFB 테스트 전후, 각각Nafion-NdZr (1%)과 Nafion-NdZr (1%) / [P-S] 2의 정량 분석을 EDX로 측정 하였다. 또한, Nafion-NdZr (1%)과 Nafion-NdZr (1%) / [P-S] 2의 XPS 분석을 통해 [P-S] 층의 존재를 밝혔다. 이 연구를 통해 개발된 분리막은 더 향상된 수명, 우수한 산화 안정성chemicalprohibitionI. INTRODUCTION ..……….….….…..1
1.1 Background ……………………………………………………………..……….….….…..1
1.2 The principle of VRFB and key components ……………………………..……….……….1
1.3 Shortcoming and current issues …………………………………………..……..……….…2
1.4 The development of membranes for VRFB ……………………………………..……...….3
1.4.1 Nafion modification with filler materials …………………………….………….......5
1.4.2 Nafion modification with ion exchange polymer ………………….……………...…6
1.4.3 Non ion exchange polymer modification ……………………………..………….…..6
1.4.4 Hydrocarbon polymer ..................................................................................................7
1.4.5 Anion exchange membranes …………………………………………….……….......8
1.4.6 Amphoteric ion exchange membranes ………………………………………....…….9
1.5 Objective of the thesis ……………………………………………………………….…....10
II. EXPERIMENTAL SECTTION…………....12
2.1 fabrication of SPAEK/Ce2Zr2O7 composite membrane ………………………………....12
2.1.1 Materials ……………………………………………………………………..………12
2.1.2 Preparation of Ce2Zr2O7 nanotubes…………………………………………..………12
2.1.3 Synthesis of hydrophilic oligomer ……………………………………………..….…12
2.1.4 Synthesis of hydrophobic oligomer ……………………………………………….…13
2.1.5 Synthesis of block copolymer (SPAEK) …………………………………………..…14
2.1.6 Preparation of SPAEK/Ce2Zr2O7 composite membrane …………………………..…14
2.2. Fabrication of Nafion-NdZr composite and Nafion-NdZr(1%)/[P-S]2 composite layer
membrane………………………………………………………………………….……15
2.2.1 Materials ……………………………………………………………………….……15
2.2.2 Preparation of Nd2Zr2O7 fillers ……………………………………………………..15
2.2.3 Preparation of Nafion-NdZr composite membrane……………………………..……15
2.2.4 Preparation of Nafion-NdZr (1%)/[P-S]2 composite layer membrane………………16
2.3 Characterization ……………………………………………………………………..….17
2.3.1 Field-emission scanning electron microscope (SEM) …………………………...…17
2.3.2 Field-emission transmission electron microscope (TEM) ………………….………17
2.3.3 Atomic force microscopy (AFM)……………………………………………….…..18
2.3.4 X-ray diffraction (XRD) ………………………………………………………....…18
2.3.5 Water uptake, Swelling degree and Ion exchange capacity (IEC) ………………....18
2.3.6 Proton conductivity …………………………………………………………….…..19
2.3.7 Oxidative stability ……………………………………………………………….…19
2.3.8 Thermal stability …………………………………………………………………...20
2.3.9 Measurements of VO2+ permeability and ion selectivity ……………………..……20
2.3.10 Measurements of vanadium flow battery performance ……………………….......21
III RESULTS AND DISCUSSION……………..…..23
3.1 SPAEK/Ce2Zr2O7 composite membrane …………………………………………..…..23
3.1.1 Characterization of SPAEK/Ce2Zr2O7 composite membrane ………………..…....23
3.1.2 Vanadium ion crossover and ion selectivity ………….............................................30
3.1.3 VRFB performance ……………………………………….......................................32
3.1.4 Thermal and mechanical properties ….………………………………………….…36
3.1.5 Oxidative and chemical stability……………………………………………….…..38
3.1.6 Post VRFB operation……………………………………………………………….39
3.2 Nafion-NdZr cmposite and Nafion-NdZr(1%)/[P-S]2 composite layer membranes …....41
3.2.1 Nd2Zr2O7 Pyrochlore nanotube and Membranes characterization …………….…..41
3.2.2 Physicochemical properties ………………………………………………………..50
3.2.3 Proton conductivity, VO2+ permeability, and ion selectivity ……………...….……52
3.2.4 VRFB performance ……………………………………………………….………..55
3.2.5 Thermal properties, Oxidative and chemical stability………………………………59
3.2.6 Post VRFB operation of composite layer membrane…………………….………....62
IV CONCLUSIONS …………………………………………………………………………....65
V REFERENCES ………………………………………………………………...…66MasterdCollectio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
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Dispelling the Myths Behind First-author Citation Counts
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use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Ultrahigh Ion-Selective and Durable Nafion-NdZr Composite Layer Membranes for All-Vanadium Redox Flow Batteries
No full textA thin
Nafion-neodymium zirconium oxide nanotube (NdZr) composite
(Nafion-NdZr) membrane has been fabricated and further modified by
the polycation, poly(diallyldimethylammonium chloride) (PDDA), and
polyanion, poly(sodium styrene sulfonate) (PSS). The ion selectivity
of the Nafion-NdZr (1%)/[P-S]2 composite layer membrane
was found to be 6.9, 3.5, and 2.3 times higher than those of recast
Nafion, Nafion/[P-S]2 layer, and Nafion-NdZr (1%) composite
membranes, respectively. As a result, the vanadium redox flow batteries
(VFBs) assembled with Nafion-NdZr (1%) composite and Nafion-NdZr (1%)/[P-S]2 composite layer membranes have surpassed the VFB performance
operated with recast Nafion and Nafion/[P-S]2 layer membranes.
Noticeably, VFB operated with the Nafion-NdZr (1%)/[P-S]2 composite layer membrane (513.7 h) exhibited a longer self-discharge
time than those with Nafion-NdZr (1%) (293.2 h), Nafion/[P-S]2 (124.1 h), and recast Nafion (32.7 h) membranes. Finally,
the single VFB cell constructed with Nafion-NdZr (1%)/[P-S]2 and Nafion-NdZr (1%) membranes remarkably showed 80.1 and 73.4%
capacity retention, respectively, over 200 charge–discharge
cycles, whereas recast Nafion exhibited a 41.5% capacity retention
over 100 cycles at a 40 mA cm–2 current density.
The structure and morphology of the Nd2Zr2O7 nanotube, Nafion-NdZr composite, and Nafion-NdZr (1%)/[P-S]2 composite layer membranes were investigated by scanning electron
microscopy, transmission electron microscopy, X-ray diffraction, Fourier
transform infrared, and atomic force microscopy analyses. Longer cyclic
performance and excellent oxidative, chemical, and thermal stability
further prove the durability of proposed membranes
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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