查找使用阿拉丁产品的科研文献

Enhanced Strength and Proton Transport in DA‑PBI/SPEEK Composite Membranes via Hydrogen-Bond-Driven Interphase Engineering

Yunhang Zhu,Yang Ke,Feiyan Lu,Hongna Jiang,Qingting Liu,Xudong Fu,Rong Zhang,Shengfei Hu,Gang Xiao,Feng Zhao,Xiao Li,Jun Yang

High-temperature proton exchange membranes (HT-PEMs) suffer from an unavoidable trade-off between proton conductivity and mechanical strength under wide-temperature and anhydrous environments. Herein, copolymerized DA-PBI/SPEEK composite membranes are fabricated via hydrogen-bond-driven interphase engineering. The sulfonic acid groups of SPEEK form intense acid-base pairs with imidazole and amino sites on DA-PBI, the synergistic effects of flexible chain segments and intermolecular hydrogen bonding significantly enhance polymer miscibility and construct a robust acid-base interaction network. Quantum chemical calculations and charge density difference (CDD) analysis confirm that the nitrogen active sites of DA-PBI anchor phosphoric acid via electronic rearrangement, which remarkably lowers the energy barrier for proton migration. The optimal membrane achieves a tensile strength of 130 MPa (3.25 times that of pristine SPEEK) and a peak power density of 0.536 W cm −2 (1.85 times that of pristine SPEEK) at 160 °C. This multi-scale strategy combining molecular chain tailoring, interfacial modulation, and electronic structure optimization resolves the conductivity-mechanical property dilemma of PBI-based membranes, offering a promising route to advanced anhydrous HT-PEMs.

Synergistic anchoring of emulsion-encapsulated phosphoric acid in cytosine-modified SPEEK toward durable direct methanol fuel cells

Bingyao Sun,Xingao Sun,Zhuo Li,Lin Yang,Hai Liu,Fuqiang Hu,Zushun Xu,Quanyuan Zhang

The development of high-performance proton exchange membranes (PEMs) for direct methanol fuel cells (DMFCs) is often constrained by a fundamental trade-off: enhancing proton conductivity typically compromises dimensional stability. While phosphoric acid (PA) doping is an effective strategy to boost conductivity, its severe leaching in aqueous environments severely limits its application in low-temperature DMFCs. Herein, we propose a novel paradigm inspired by pharmaceutical encapsulation to overcome this challenge. A stable water-in-oil (W/O) emulsion is designed to encapsulate hydrophilic PA, which is then blended with a cytosine-functionalized SPEEK matrix. This innovative approach enables adjustment of the acid doping level (ADL). More importantly, it establishes a dual-retention mechanism: the quaternary ammonium groups of the emulsifier (STDAB) form ionic bonding with H 2 PO 4 − anions within the emulsion droplets, while the basic –NH– groups of cytosine act as molecular anchors for free PA via acid-base interactions. The synergistic effect of physical encapsulation and chemical anchoring endows the fabricated composite membrane with exceptional performance. It achieves a remarkable proton conductivity of 174.9 mS cm −1 at 80 °C, which is 2.3 times that of pristine SPEEK. Furthermore, the membrane exhibits outstanding operational stability, retaining 85.5 % of its voltage after 280 h of continuous operation, underscoring its significant potential for practical DMFC applications.

Investigation of Diamine Cross-Linker on Semi-IPNs of BPPO/SPEEK Membranes for Direct Methanol Fuel Cell

Xupo Liu,Yunfeng Zhang,Yazhou Chen,Cuicui Li,Jiaming Dong,Jiaying Wang,Zehui Yang,Hansong Cheng

Low methanol permeability is one of the most critical factors for proton exchange membranes utilized in direct methanol fuel cells (DMFCs). Here, sulfonated poly(ether ether ketone) (SPEEK) polymer chains are interpenetrated into the semi-interpenetrating polymer networks (semi-IPNs) constructed by the alkylation reaction between bromobenzyl groups of bromomethylated poly(phenylene oxide) and amine groups of 2,2′-(ethylenedioxy)bis(ethylamine) cross-linker. The influences of crosslinking network contents on the key properties of SPEEK membranes are systematically investigated. Dimensional stability and methanol-permeability resistance are enhanced as the increase of the crosslinking network contents. The relative selectivity is significantly improved due to the largely reduced methanol permeability. The DMFC assembled by the membrane with 20 wt.% crosslinking networks demonstrates four times higher power output than the Nafion 117 DMFC in 5 M methanol solution.

Widening CO2-facilitated transport passageways in SPEEK matrix using polymer brushes functionalized double-shelled organic submicrocapsules for efficient gas separation

Qingping Xin,Huanran Liu,Yuan Zhang,Hui Ye,Shaofei Wang,Ligang Lin,Xiaoli Ding,Bowen Cheng,Yuzhong Zhang,Hong Wu,Zhongyi Jiang

Appropriate facilitated transport carriers and water environment are two principal factors for efficient CO 2 membranes separation . In this study, the facile distillation-precipitation polymerization (DPP) and atom transfer radical polymerization (ATRP) methods are consecutively used to prepare polymer brushes functionalized double-shelled organic submicrocapsules, and the resultant organic submicrocapsules are incorporated into sulfonated poly(ether ether ketone) (SPEEK) to fabricate mixed matrix membranes (MMMs). The doubled-shelled structure provides abundant facilitated carriers by the outer shell and high water retention property by the inner shell simultaneously. The organic submicrocapsules (b-IM@PMMA) are homogeneously embedded in the SPEEK matrix, and abundant amine groups on polymer brushes of outer shell increase the content of CO 2 -facilitated transport sites in MMMs. The inner shell renders the organic submicrocapsules of higher water content, yielding the MMMs with enhanced water retention properties. Moreover, the incorporation of organic submicrocapsules increases the water uptake and water retention capacity of MMMs. The MMMs doped with organic submicrocapsules display better CO 2 separation performance than the MMMs doped with double-shelled organic submicrocapsules without brushes. The polymer brushes functionalized double-shelled organic submicrocapsules act as water reservoirs to not only offer more water for the dissolution of CO 2 gas molecules, but also construct and widen interconnected continuous CO 2 -facilitated transport passageways. The highest CO 2 /CH 4 (N 2 ) selectivity is 73.8(76.3) for the SPEEK/b-IM@PMAA MMMs (at a CO 2 permeability of 2236 Barrer) in pure gas, surpassing the 2008 Robeson upper bound.

Sandwich-structure PI/SPEEK/PI proton exchange membrane developed for achieving the high durability on excellent proton conductivity and stability

Peng Wei,Yang Sui,Xi Li,Qingkun Liu,Bensheng Zhu,Chuanbo Cong,Xiaoyu Meng,Qiong Zhou

The proton exchange membrane (PEM) is the core unit in fuel cells, in which the balance among proton conductivity, dimensional stability and durability is a long-term pursuit. Nanofiber composite membrane as the most facile and practical strategy, however, commonly suffers from the obviously reduced proton conductivity although the dimensional stability and durability can be improved distinctly. Herein this work, we proposed a sandwich-structure nanofiber composite PEM, in which the inexpensive proton-transport matrix of sulfonated poly (ether ether ketone) (SPEEK) is sandwiched between polyimide (PI) nanofibers mats via simple steps. Thanks to the support for the matrix and resistance to the tough working condition provided by the PI nanofiber mats, significantly improved stability and durability in contrast to the referenced PEM of SPEEK. More importantly, with respect to the proton conductivity, a numerically equivalent initial proton conductivity and significantly improved proton conductivity stability, in comparing to the SPEEK membrane, has been achieved; where the conductivity only decreased by 21% in our sandwich-structure PEM after 6 weeks, much less than that of commercial Nafion 117 of 30% and pure SPEEK of 55%. Such results can be attributed to the hydrogen bond interaction between PI nanofibers and SPEEK matrix and thus the formation of the sulfonic acid-rich layer in our developed PI/SPEEK/PI membrane, confirmed by in situ Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). This combination of high proton conductivity, long-term stability, low cost, simple preparation suggests the sandwich-like PEM will provide a promising commercial application for future PEMs.

NH2-UiO66 functionalized polyimide nanofiber to anchor HPW and fabricate high-performance sandwich-structure membrane for achieving excellent durability

Peng Wei,Yang Sui,Dong Huang,Bensheng Zhu,Xiaoyu Meng,Qiong Zhou

Sulfonated poly ether ether ketone (SPEEK) was used to fabricate proton exchange membrane (PEM) due to its adaptable proton conductivity. However, PEM cannot simultaneously enhance its conductivity and stability. To solve the problem mentioned above, phosphotungstic acid (HPW) with strong inherent proton conductivity was chosen to add to the SPEEK matrix, but it still faces the leaky problem. NH 2 -UiO-66 (NU6) with a large surface area and chemical stability was synthesized in situ on the surface of polyimide (PI) nanofiber to create NU6@PI nanofiber, which can be used to anchor HPW. Meanwhile, the stability of proton transport channel may be further enhanced by the sandwich structure, which may be advantageous for proton transport. The NU6@PI/SPEEK + HPW-20 exhibited a conductivity of 174.9 mS·cm −1 and a swelling ratio of 19 % at 60 °C and 100 % RH. After 6 weeks of testing, its conductivity decreased to 151.2 mS·cm −1 which was 24 % higher than that of SPEEK, while the swelling ratio increased to 31 % which was lower than that of SPEEK. The outcome demonstrates that the sandwich-structure NU6@PI/SPEEK + HPW membrane may really boost proton conductivity and stability at the same time. By using XPS and TEM, it is possible to confirm the acid-base interaction and acid-rich layer that exist at the interfaces of NU6@PI nanofiber and HPW/SPEEK matrix. After 6-weeks of usage, the sandwich-structure composite membrane with nanofiber at both the top and bottom of PEM can still maintain high proton conductivity and high stability, offering a novel research idea for resolving the issue that PEM cannot simultaneously achieve significant proton conductivity as well as elevated stability.

Self-Humidifying and Super-Protonic Conductivity of SPEEK-Based Composite Proton Exchange Membranes Incorporated by Functionalized MXene and Modified TiO2 Nanofillers

Manting Huang,Ai Song,Xingliu Ben,Weijia Ji,Yuxuan Pan,Huaxin Rao

MXene, as a suitable and alternative 2D nanofiller incorporated into a proton exchange membrane (PEM), has recently received considerable attention because of desired mechanical stability, promising conductivity, and active surface functional groups. However, agglomeration or sedimentation in PEMs, as well as the water retention capacity under low humidity of MXene, are limiting factors in the field of PEMs. In this paper, modified MXene and TiO2nanoparticles used as functional nanofillers were incorporated into sulfonated poly (ether ether ketone) (SPEEK) to prepare novel SPEEK-based composite PEMs. The effects of the nanofiller contents on self-humidifying and protonic conductivity of the composite PEMs were also investigated under different temperatures. When the contents of functionalized MXene and modified TiO2are 5 wt.%, proton conductivity, water uptake and methanol permeability of the composite PEMs can be up to 0.143 S/cm, 60% and 2.27 × 10−7cm2/s, respectively, which represent increases of about 192%, about 38% and a decrease of 47%, respectively, compared with that of primary SPEEK PEM. Under the synergistic action of functionalized MXene providing a higher number of exchangeable proton sites, modified TiO2with inherent hydrophilicity enhancing water retention and Pt providing catalytic sites for the H2/O2reaction to generate water in situ, the self-humidifying capability and proton conductivity of the composite PEMs were improved significantly.

Anchoring of Fe-MIL-101-NH2 to the Polymer Membrane Matrix through the Hinsberg Reaction to Promote Conductivity of SPEEK Membranes

Hong-Jie Zhang,Xue-Bin Shang,Xu-Ran Wang,Chen-Xi Zhang,Qing-Lun Wang

SCPEEK@MOF proton exchange membranes, where SCPEEK is sulfinyl chloride polyether ether ketone and MOF is a metal–organic framework, were prepared by doping Fe-MIL-101-NH2 into polymers. The amino group in the MOF and the -SOCl2 group in thionyl chloride polyether ether ketone cross-link to form a covalent bond through the Hinsberg reaction, and the prepared composite membrane has stronger stability than other electrostatic interactions and simple physical doping composite membranes. The formation of covalent bonds improves the water absorption of the composite membrane, which makes it easy for water molecules to form hydrogen bonds. Moreover, SPEEK as a proton conductive polymer and the synergy of MOFs improve the proton conductivity of composite membranes. The composite membranes were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The swelling rate, water absorption, mechanical stability, ion exchange capacity, and proton conductivity of the pure sulfonated polyether ether ketone (SPEEK) membrane were compared with those of the mechanically doped SPEEK/MOF membrane and the composite membrane SCPEEK@MOF doped with different ratios of Fe-MIL-101-NH2, and all of the SCPEEK@MOF showed superior performance. When the Fe-MIL-101-NH2 loading rate of the composite membrane is 2%, the proton conductivity of the composite membrane can reach 0.202 S cm–1 at 363 K and a 98% relative humidity, which is much higher than that of the SPEEK/MOF membrane obtained by simple physical doping under the same conditions.

Ultra-high Prussian blue loading in SPEEK matrix fabricated by one-step electrostatic spraying as proton exchange membranes for fuel cell

Weiming Yu,Ziyao Cui,Qining Wang,Zihao Fan,Tiantian Li,Bo Pang,Fujun Cui,Xuemei Wu,Gaohong He

Mixed matrix proton exchange membrane is promising for fuel cell application, but maximizing nanofiller loading to enhance performance is significant challenge. This study developed a one-step electrostatic spraying strategy to prepare ultra-high Prussian blue loading (up to 66.7 wt%) in sulfonated poly (ether ketone) matrix (PB@SPEEK). By coupling the electrostatic spraying and in situ solvent evaporation densification, SPEEK fills the voids between PB nanoparticles, forming a bicontinuous microstructure in the membrane. The ultra-high PB content of 66.7 wt% enable a fully utilization of its intrinsic properties, resulting in extremely low swelling ratio of 3.4 % at 80 °C, excellent flexibility of freely folding, and nearly 100 % mass retention after 12-h immersion in Fenton reagent at 60 °C. In single-cell tests, the PB@SPEEK mixed matrix membrane shows stable internal resistance due to easily water hydration, therefore achieving excellent low-temperature peak power (1973.9 mW/cm 2 at 40 °C and 2078.0 mW/cm 2 at 60 °C). The strategy developed in this study enables the one-step preparation of large-area, ultra-thin and ultra-high capacity of inorganic nanofiller mixed matrix proton exchange membranes for high-performance fuel cell.

A Novel Polymer-Salt Complex Based on LiCl Doped SPEEK/Poly(Ether Ether Ketone)-Co-Poly(Ethylene Glycol) for Humidity Sensors

Zhuang Zhuang,Yunfeng Li,Xifang Li,Chengji Zhao

Phosphoric acid-doped Gemini quaternary ammonium-grafted SPEEK membranes with superhigh proton conductivity and mechanical strength for direct methanol fuel cells

Juan Wu,Fei Wang,Xiangjian Fan,Jiale Chu,Fan Cheng,Fuqiang Hu,Hai Liu,Quanyuan Zhang,Zushun Xu,Chunli Gong

Proton exchange membranes (PEMs) with excellent proton conductivity, high mechanical strength , and low methanol permeability are essential for their application in direct methanol fuel cells (DMFCs). Herein, flexible alkyl side chains containing Gemini quaternary ammonium (QA) ions were grafted onto sulfonated poly(ether ether ketone) (SPEEK) to obtain novel amphiphilic polymers (S-DMEAx-BPT), and then doped with phosphoric acid (PA) to prepare S-DMEAx-BPT/PA membranes. PA immobilized on flexible side chains can possess more mobility and higher proton conduction ability when compared with PA bound to rigid main chains, thus contributing to the extremely high proton conductivity of S-DMEAx-BPT/PA (295.4 mS cm -1 , 80 °C, 100% R.H) even at low PA doping levels. Moreover, with the help of abundant ionic crosslinking, the membranes had excellent dry and wet mechanical properties . Benefiting from the negligible PA leaching, these membranes could be used as the electrolyte in DMFCs and output the peak power density of 110.7 mW cm -2 , which was 2.1 times that of Nafion 212 (52.8 mW cm -2 ). Moreover, the open-circuit voltages (OCV) retention remained at 82.4% after 140 h. Therefore, the strategy combining Gemini QA cations grafting, flexible side chains, and low-level PA doping provides a new methodology for fabricating high-performance PEMs for DMFCs.

Preparation of an Amidated Graphene Oxide/Sulfonated Poly Ether Ether Ketone (AGO/SPEEK) Modified Atmosphere Packaging for the Storage of Cherry Tomatoes

Yao Cheng,Hao Dong,Yuanyue Wu,Kaijun Xiao

The shelf life of cherry tomatoes is short so that new and efficient preservation techniques or procedures are required to reduce postharvest losses. This study focused on the development of a sulfonated poly ether ether ketone (SPEEK) film incorporated with amidated graphene oxide (AGO), for the storage of cherry tomatoes in modified atmosphere packaging. The mechanical properties, gas permeability, and moisture permeability were subsequently tested. The evolution of attributes related to shelf life, such as gas composition, physicochemical properties, and sensory properties were also monitored during storage trials. AGO, as an inorganic filler, increases the thermal stability and mechanical properties of SPEEK-based films, while it reduces the water absorption, swelling rate, and moisture permeability. Importantly, all the AGO/SPEEK films exhibited enhanced gas permeability and selective permeability of CO2/O2relative to the SPEEK film. Moreover, 0.9% (w/w) AGO/SPEEK film showed an enhanced permeability coefficient of CO2, corresponding to an increase of 50.7%. It could further improve the selective coefficient of CO2/O2to 67.1%. The results of preservation at 8 °C revealed that: 0.9% (w/w) AGO/SPEEK film was significantly effective at maintaining the quality and extending the shelf life of cherry tomatoes from 15 to 30 days, thereby suggesting the potential for applying AGO-incorporated SPEEK films for food packaging materials.Keywords:amidated graphene oxide;sulfonated poly ether ether ketone;modified atmosphere film;cherry tomatoes;food packaging