JOURNAL OF POWER SOURCES
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2023
·
IF 9.2
Hongying Tang,Ge Chao,Jian Gao,Yuntao Shang,Nanwen Li,Kang Geng
To further mitigate the phosphoric acid leakage in high temperature proton exchange membrane (PEM), the microporosity of Tröger's base (TB) membrane based on a V-shaped bridged bicyclic diamine has been fine-tailored readily by polymeric blending with a miscible polymer of intrinsic microporosity (PIM-1). As expected, the average cavity radius in the range of 3.46–4.21 Å has been achieved when the blending ratio of PIM-1 increases from 5 to 20 mol% due to the interaction between the amine group of TB and the nitrile group of PIM-1. The resulting PEMs show excellent PA retention ability. Notably, PIM/TB9 membrane with a suitable cavity radius of 3.5 Å and largest FFV 4 of 49.1% exhibits an exciting PA retention of about 80%, which is much better than the pristine TB membrane. Thus, the remaining proton conductivity of PIM/TB9 is almost 5 times higher than that of TB membrane after 22 relative humidity cycle tests. Moreover, the resulting cell can run smoothly within a wide temperature range from 0 to 160 °C. The single cell performs for over 150 AST cycles and remains stable for >600 h with no visible voltage decay at 80 °C. Therefore, these results indicate the technical feasibility to improve the PA retention via fine-tuning the intrinsic microporosity of the PEMs through a direct blending method.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
ADVANCED MATERIALS
·
2023
·
IF 29.4
Wen Li,Wen Liu,Wendi Jia,Jin Zhang,Qi Zhang,Zhenguo Zhang,Jialin Zhang,Yunqi Li,Yiyang Liu,Haining Wang,Yan Xiang,Shanfu Lu
The properties of proton conductors determine the operating temperature range of fuel cells. Typically, phosphoric acid (PA) proton conductors exhibit excellent proton conductivity owing to their high proton dissociation and self-diffusion abilities. However, at low temperatures or high current densities, water-induced PA loss causes rapid degradation of cell performance. Maintaining efficient and stable proton conductivity within a flexible temperature range can significantly reduce the start-up temperature of PA-doped proton exchange membrane fuel cells. In this study, a dual-proton conductor composed of an organic phosphonic acid (ethylenediamine tetramethylene phosphonic acid, EDTMPA) and an inorganic PA is developed for proton exchange membranes. The proposed dual-proton conductor can operate within a flexible temperature range of 80–160 °C, benefiting from the strong interaction between EDTMPA and PA, and the enhanced proton dissociation. Fuel cells with the EDTMPA-PA dual-proton conductor showed excellent cell stability at 80 °C. In particular, under the high current density of 1.5 A cm −2 at 160 °C, the voltage decay rate of the fuel cell with the dual-proton conductor is one-thousandth of that of the fuel cell with PA-only proton conductor, indicating excellent stability.
研究领域:
材料科学
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能源工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
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2012
·Vol. 19
·期 10
·1-12
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IF 1.733
Hu Meiping,He Xiaohui,Chen Yiwang,Chen Defu
Novel copolynorbornenes bearing pendant sultone groups (designated as P(BN/SulNBOH) and P(BN/SulNBOMe)) have been successfully synthesized via copolymerization of functionalized norbornenes bearing sultones (designated as SulNBOH and SulNBOMe) with 2-butoxymethylene norbornene (BN). The catalyst system showed high catalyst activity (10 4 g polymer /mol Ni ·h) and the obtained copolymers have high molecular weight and a narrow molecular weight distribution. Furthermore, the achieved copolymers P(BN/SulNBOH) and P(BN/SulNBOMe) were converted into sulfonated copolymers sP(BN/NBOH) and sP(BN/NBOMe). Both sP(BN/NBOH) and sP(BN/NBOMe) membranes displayed low water uptake, high thermal properties, good mechanical properties, and better proton exchange membranes properties. The proton conductivities measured in the hydrated state at 80 °C ranged from 10 −5 to 7.19 × 10 −3 S·cm −1 .
Novel copolynorbornenes bearing pendant sultone groups are synthesized. The achieved copolymers are converted into the sulfonated copolymers. The proton conductivities of the membranes measured in the hydrated state at 80 °C ranged from 10 −5 to 7.19 × 10 -3 S·cm −1 .
研究领域:
材料科学
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化学工程
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DOI
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 42
·24772-24783
·
IF 3.119
Shouping Wang,Fugang He,Qiang Weng,Diao Yuan,Pei Chen,Xinbing Chen,Zhongwei An
A series of novel crosslinkable side-chain sulfonated poly(arylene ether sulfone) copolymers (S-SPAES(x/y)) was prepared from 4,4′-biphenol, 4,4′-difluorodiphenyl sulfone, and a new difluoro aromatic monomer 1-(2,6-difluorophenyl)-2-(3,5-dimethoxyphenyl)-1,2-ethanedione (DFDMED) via co-polycondensation, demethylation, and further nucleophilic substitution of 1,4-butane sultone. Meanwhile, quinoxaline-based crosslinked copolymers (CS-SPAES(x/y)) were obtained via cyclo-condensation between S-SPAES(x/y) and 3,3′-diaminobenzidine. Both the crosslinkable and crosslinked copolymer membranes exhibit good mechanical properties and high anisotropic membrane swelling. Crosslinkable S-SPAES(1/2) with an ion exchange capacity (IEC) of 2.01 mequiv. g−1 displays a relatively high proton conductivity of 180 mS cm−1 and acceptable single-cell performance, which is attributed to its good microphase separation resulting from the side-chain sulfonated copolymer structures. Compared with S-SPAES(1/1) (IEC of 1.68 mequiv. g−1), crosslinked CS-SPAES(1/2) with a comparable IEC exhibits a larger conductivity of 157 mS cm−1, and significantly higher oxidative stability and lower membrane swelling, suggesting a distinct performance improvement due to the quinoxaline-based crosslinking.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Jianjian Yang,Changsong Xie,Qinglei Guo,Hui Wang,Xing Zhou,Zhelun Li,Zixi Kang,Rongming Wang,Daofeng Sun
Proton exchange membrane fuel cells (PEMFCs) are regarded as one of the most promising clean and highly efficient power generation technologies. However, obtaining proton exchange membranes with superior performance remains a challenge for the development of PEMFCs. In this work, we synthesized a porous polyhydroxyl polymer, known as BTA, and successfully introduced almost equimolar phosphate and sulfonic acid groups (−SO3H and −PO4H2) into its framework through the simple postmodification process, resulting in BTA-P and BTA-S, respectively. The studies showed that the −SO3H group in BTA-S can ionize a large number of available protons, and its ion exchange capacity (IEC) reaches 1.65 mmol g–1, which is twice higher than that of BTA-P. The available protons can greatly enhance the proton transport efficiency, resulting in a 3 orders of magnitude increase in proton conductivity of BTA-S compared to BTA-P, reaching up to 3.97 × 10–1 S cm–1 at 80 °C and 95% relative humidity (RH). When a 5% BTA-S/Nafion composite is prepared as a proton exchange membrane for an H2/O2 fuel cell, the maximum power density reaches 952.6 mW cm–2, which is 61.9% higher than that of the recast Nafion membrane at 80 °C and 100% RH. This study reveals that the available proton density plays the most important role in proton conducting polymers.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Xiaoyu Meng,Luman Peng,Yuanyuan Wang,Xiaojing Li,Qiwang Peng,Xiaocan Zhang,Chuanbo Cong,Haimu Ye,Qiong Zhou
Nanofibers have been widely used in the construction of proton exchange membranes(PEM), which can be used to modify Nafion membranes and enhance their mechanical properties. With the addition of nanofibers, some of the sulfonic acid active sites in the perfluorosulfonic acid matrix are occupied, and the conductivity decreases. A covalent organic framework (COF) can be used to compensate for this. In this paper, hybrid COFs modified with sulfonic and pyridine groups were selected and synthesized in situ on polyacrylonitrile (PAN) fibers, and the fibers were placed in a perfluorosulfonic acid matrix to form a sandwich shaped composite membrane . The hybrid COF generates a small fiber-like structure to connect the PAN fibers, which improves the connectivity between three-dimensional nanofibers. This structure also plays a role in enhancing longitudinal proton transport ability of the composite membrane, which provides a new idea in the study of PEM.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2020
·
IF 1.568
Xiang Sun,Fan Zhu,Xiaoyang Liu,Hongqian Ren,Minglong Xia,Mengjie Yang,Yi Feng,Huili Ding
The development of a proton exchange membrane (PEM) that can avoid rapid decay of proton conductivity under low humidity is of great significance for the practical application of PEMFC. In this study, acid–base core–shell microspheres (PCSMs-MA@TAC) with a carboxylic acid core and a triazine shell were synthesized by distillation-precipitation polymerization using cross-linked carboxylic acid microspheres (PMAA) as seeds. These PCSMs were then incorporated into a sulfonated poly(ether ether ketone) matrix to make hybrid membranes. Incorporation of PCSMs microspheres can not only strengthen the vehicle mechanism by increasing the water uptake of the membrane, but also the acid–base pairs formed at the SPEEK/PCSMs interface provide a new low-energy barrier pathway for proton hopping, thereby enhancing the proton conduction of the Grotthuss mechanism. The results show that when the content is 10 wt%, the proton conductivity of the SPEEK/PCSMs-MA@TAC composite membrane can reach 0.161 S cm−1 at 80°C and 100% RH, which is 19.3% higher than the SPEEK control membrane (0.135 S cm−1). In particular, even at 60% RH, the proton conductivity of the SPEEK/PCSMs-MA@TAC-10 composite membrane is still 67 mS cm−1, which is 3.16 times higher than that of the SPEEK membrane. Therefore, the SPEEK/PCSMs-MA@TAC composite membrane can maintain superior performance even under high temperature and low humidity conditions.
研究领域:
材料科学
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能源科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2020
·
IF 4.231
Xuehua Zhou,Bensheng Zhu,Xiangwei Zhu,Jiaojiao Miao,Xiangnan Sun,Qiong Zhou
In this article, a novel proton exchange membrane , shown both high proton conductivity and excellent stability, has been demonstrated, which is simply fabricated by embedding poly(vinylidene fluoride) grafted poly(styrene sulfonic acid) (PSSA-g-PVDF) nanofibers in sulfonated poly (ether ether ketone) (SPEEK) matrix. The novel nanofiber-enhanced membrane (NEM) presents an utlra-high proton conductivity of 720.6 mS/cm, which is 2.4 times higher than the unmodified SPEEK membrane. The long-range continuous proton transport channel built at the interface between the matrix and nanofibers, known as acid-condensed layer, has been directly confirmed by transmission electron microscopy (TEM) measurements for the first time, which illustrates the result. Futhermore, the NEMs are always provided with the excellent dimensional, thermal, and mechanical stability , which benefit from the sturdy three-dimensional network of PSSA-g-PVDF nanofibers. In virtue of the high conductivity and stability, the NEMs have proved to be very promising in fuel cells.
研究领域:
材料科学
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能源技术
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Yahui Wang,Shaoyun Hao,Xiangnan Liu,Qiqi Wang,Zhiwei Su,Lecheng Lei,Xingwang Zhang
Electrocatalytic water splitting in acidic media based on a proton-exchange membrane (PEM) is a promising technique for the large-scale production of hydrogen. However, developing electrocatalysts with high activity and excellent stability for an oxygen evolution reaction (OER) in acidic media is still a big challenge. Herein, a Cex-IrO2 catalyst supported on N-doped porous carbon (NPC) was developed via doping Ce into IrO2 nanoparticles. The Cex-IrO2 nanoparticles were uniformly distributed on NPC due to the high surface area. The optimized Ce0.2-IrO2@NPC delivers a low overpotential of 224 mV and excellent stability of 100 h in 0.5 M H2SO4 at 10 mA cm–2. Density functional theory (DFT) calculations indicated that the introduction of Ce could modify the electronic structure of IrO2, decreasing the energy barrier of the rate-determining step for OER and enhancing the electrochemical OER performance. Our work opens up a new way of developing anodic electrocatalysts, which can be stably applied in acidic media.
研究领域:
材料科学
·
电化学
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能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Xiangwen Zhang,Yi Li,Xin Liu,Junfeng Zhang,Yan Yin,Michael D. Guiver
A new class of proton exchange membranes (PEMs) containing ferrocyanide groups as both proton-conducting/radical scavenger components are fabricated. Here, the ferrocyanide groups are bonded to a commercial fluoroelastomer polymer main chain, resulting in ferrocyanide-coordinated PEMs (CFC) for proton exchange membrane fuel cells (PEMFCs). The CFC PEMs show a larger hydrophilic morphological phase than Nafion 212 membrane, even in the CFC having lower ion exchange capacity, owing to stronger electrostatic forces among ferrocyanide groups than traditional sulfonic groups. Compared with Nafion 212, CFC membranes present inferior proton conductivity in water. However, they show much lower activation energy for proton transport in water, and considerably higher proton conductivity than Nafion 212 under low relative humidity (RH). This is related to the larger hydrophilic domains that may construct better-connected channels for proton transport, especially at low membrane hydration levels. As a result, CFC membranes exhibit better power output than Nafion 212 in PEMFC evaluations under low RH conditions. The chemical accelerated stress test (AST) demonstrates that the radical scavenging ability of ferrocyanide group is effective for greatly reducing electrochemical oxidation .
研究领域:
材料科学
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化学工程
·
能源技术
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Youxiu Huo,Qingbing Li,Zhiyan Rui,Rui Ding,Jia Liu,Jia Li,Jianguo Liu
The need to reduce the cost of proton exchange membranes (PEMs) leads to less usage of perfluorinated sulfonic acid (PFSA), which would definitely result in a decline in the membrane lifespan under the attack of free radicals. In this study, polytetrafluoroethylene (PTFE) is used as a reinforced material to make a thinner composite membrane due to the poor mechanical strength of the pristine membrane. Moreover, a polydopamine (PD)-treated strategy was selected to make hydrophilic PTFE, which allows the adoption of a high-boiling point solvent for the dissolution of resveratrol , a natural antioxidant produced by plants that acts as a free radical scavenger (FRS) in the membrane to prevent the membrane from being attacked. With the help of dimethyl formamide (DMF), a high-boiling point solvent, and hydrophilic groups in PD molecules, a Nafion/PD@PTFE/resveratrol composite membrane with a thickness of 10 μm was prepared and tested using an accelerated degradation test (ADT) strategy. With a resveratrol dose of 1 wt%, the cell presented a lower hydrogen crossover of 2.82 mA cm −2 and a longer lifespan than those of a membrane without resveratrol while cell performance did not suffer too much damage. In the ADT experiment, the hydrogen crossover of Nafion/PD@PTFE/resveratrol was still less than 20 mA cm −2 after 8 open circuit voltage (OCV) cycles, while that without resveratrol increased to 80 mA cm −2 in 3 OCV cycles.
研究领域:
材料科学
·
能源化学
·
生物学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Yating Li,Xiaolong Zhang,Gaohong He,Fengxiang Zhang
Low oxidation stability is one of the key issues hindering practical application of non-fluorinated proton exchange membrane in fuel cells. As a part of the efforts to address this issue, we herein report a novel hydrocarbon proton exchange membrane of polysulfone (PSf) grafted with sulfonated poly(phenylene sulfide) (sPPS). The proton conductivity , thermal and oxidation stability of the PSf-g-sPPS membranes were studied and compared against those of conventional polysulfone-graft-sulfonated polystyrene (PSf-g-sPS) membranes. The PSf-g-sPPS membranes exhibited superior chemical stability relative to those of PSf-g-sPS membranes: the mass retention ratio of former is 10% higher than that of latter after treatment in Fenton's reagent. Additionally, the conductivity retention ratio of PSf-g-sPPS membranes at 23% graft degree is ca. 30% higher than those of PSf-g-sPS membranes. In terms of thermal stability, the PSf-g-sPPS complete degradation temperature is higher than PSf-g-sPS complete degradation. Based on our study, grafting of aromatic side chain is effective to improve the oxidation stability of non-fluorinated PEM while maintaining good conductivity and swelling resistance.
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）