In situ implantation of cross-linked functional POSS blocks in Nafion® for high performance direct methanol fuel cells

Li, Zhen; Hao, Xiaofeng; Cheng, Geng; Huang, Sheng; Han, Dongmei; Xiao, Min; Wang, Shuanjin; Ye, Meng

doi:10.1016/j.memsci.2021.119798

Cited by 27 publications

(8 citation statements)

References 52 publications

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“…31 In other words, the bright and dark regions correspond to the hydrophilic domains and hydrophobic domains, respectively, in the adhesion map. 33 Figure S5d−f illustrates that the film surface roughness of three substrate types (0.62, 0.793, and 1.22 nm) under liquid water was basically the same as that measured in the atmosphere. As shown in Figure 4d−f, the bright regions of films on the bare SiO 2 substrate are long, narrow, and interconnected, while such a network is relatively less continuous of films on the NH 3 + −SiO 2 substrate.…”

Section: Phase Separationmentioning

confidence: 57%

“…The phase difference between hydrophobic regions and hydrophilic regions was interpreted as the preferential adsorption of water on hydrophilic regions, resulting in a more adherent surface . In other words, the bright and dark regions correspond to the hydrophilic domains and hydrophobic domains, respectively, in the adhesion map Figure S5d–f illustrates that the film surface roughness of three substrate types (0.62, 0.793, and 1.22 nm) under liquid water was basically the same as that measured in the atmosphere.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Substrate Surface Charges on Proton Conduction of Ultrathin Nafion Films

Yuan

et al. 2023

ACS Appl. Mater. Interfaces

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A potential approach to enhance the suppressed proton conductivity of nanoscale ultrathin Nafion films is to adjust the ionomer structure via regulating the catalyst–ionomer interaction. To understand the interaction between substrate surface charges and Nafion molecules, self-assembled ultrathin films (∼20 nm) were prepared on the SiO2 model substrates, which were modified with silane coupling agents to carry either negative (COO–) or positive (NH3 +) charges. Specifically, the surface energy, phase separation, and proton conductivity were investigated by contact angle measurements, atomic force microscopy, and microelectrodes to illuminate the relationship between the substrate surface charge, thin-film nanostructure, and proton conduction. Compared to electrically neutral substrates, ultrathin films formed faster on the negatively charged substrate with an 83% increase in proton conductivity but formed more slowly on the positively charged substrate, with proton conductivity decreased by 35% at 50 °C. The surface charges interact with sulfonic acid groups of Nafion molecules to alter molecular orientation, resulting in different surface energies and phase separation, which are responsible for proton conductivity variation.

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Section: Phase Separationmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Effect of Substrate Surface Charges on Proton Conduction of Ultrathin Nafion Films

Yuan

et al. 2023

ACS Appl. Mater. Interfaces

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“…The DMFC assembling this membrane exhibited twice higher power density than Nafion 212. 28 Viviani et al prepared a series of octa-glycidyl POSS and poly(phenylene sulfide benzimidazole) thermally cross-linked membranes. The obtained membranes showed good oxidative stability in Fenton's reagent after 264 h at 80 °C.…”

Section: Introductionmentioning

confidence: 99%

“…The membrane bearing Vi -POSS-SO 3 Na showed a significantly high proton conductivity of 121 mS cm –1 at 80 °C. The DMFC assembling this membrane exhibited twice higher power density than Nafion 212 . Viviani et al prepared a series of octa-glycidyl POSS and poly(phenylene sulfide benzimidazole) thermally cross-linked membranes.…”

Section: Introductionmentioning

confidence: 99%

Surface-Modified Approach to Fabricate Nafion Membranes Covalently Bonded with Polyhedral Oligosilsesquioxane for Vanadium Redox Flow Batteries

Zhang

et al. 2022

ACS Appl. Mater. Interfaces

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An aminopropyl isobutyl polyhedral oligosilsesquioxane (NH2-POSS) surface-modified Nafion membrane has been designed by chemical grafting for vanadium redox flow batteries (VRFBs). NH2-POSS is a cage-like macromer consisting of an inorganic Si8O12 core surrounded by seven inert isobutyl groups and one active aminopropyl group. The sulfonic acid groups on the surface of Nafion can be activated by 1,1-carbonyldiimidazole for further modification with NH2-POSS. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) prove that NH2-POSS has been successfully grafted on the surface of a Nafion 115 membrane. Although the proton conductivity decreases slightly, the organic–inorganic hybrid membranes display enhanced ion selectivity and excellent dimensional stability with lower water uptake and swelling ratio than Nafion 115. Moreover, two-dimensional-grazing incidence X-ray diffraction (2D-GIXRD) reveals that the introduction of NH2-POSS forms a POSS layer on the surface of the membrane and narrows the space of Nafion clusters, which helps to block VO2+ permeation. A VRFB with the surface-modified Nafion membrane displays an outstanding performance with an average Coulombic efficiency (CE) of 98.7% and energy efficiency (EE) of 84.5% at a current density of 80 mA cm–2, superior to those of the Nafion 115 membrane (CE = 95.7%, EE = 81.7%). Furthermore, the cell holds a high capacity retention of 49.2% after 1000 charge–discharge cycles, in contrast to that of 41.9% for the cell with Nafion 115 after only 200 cycles. The results suggest that the surface-modified hybrid membrane is a promising strategy to overcome the vanadium ion crossover in VRFBs.

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“…In rechargeable batteries or fuel cells, ion diffusion is inhibited by inserting separation materials (such as polyhedral oligomeric silsesquioxane (POSS) and ethylene dimethacrylate (EDMA) based polymers) as proton exchange membranes [44][45][46][47] . POSS consists of a rigid, cubic Si-O-Si cage-type core with eight ethylene groups that can bridge the linear EDMA in various directions via olefin polymerization.…”

mentioning

confidence: 99%

Crosslinked ion diffusion inhibitors stabilize 3D/2D perovskite heterostructures for efficient and stable photovoltaics

Lu¹,

Zeng

Wang

et al. 2022

Preprint

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Two-dimensional (2D) and quasi-2D modifications of 3D perovskite active layers have contributed to advances in the performance of perovskite solar cells (PSCs); however, the ionic diffusion between the surface 2D and bulk 3D perovskites leads to the degradation of the 2D/3D perovskite heterostructure and limits the long-term stability of PSCs. Here we incorporate a crosslinked ion diffusion inhibitor (CDI) on the top of a 3D perovskite layer, and then deposit a 2D perovskite layer via a vapor-assisted two-step process to form a 3D/CDI/2D perovskite heterostructure. Photoluminescence spectra and thickness-profiled elemental analysis indicate that it is by inhibiting ion diffusion between the 2D and 3D perovskites that the CDI stabilizes the heterostructures. Based on carbon electrodes, we report small-area devices with an efficiency of 21.17%, and mini-modules with an efficiency of 19.56%. After 4,390-hours operation under maximum power point tracking and one-sun illumination at elevated temperature, devices retain 90% of initial performance.

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In situ implantation of cross-linked functional POSS blocks in Nafion® for high performance direct methanol fuel cells

Cited by 27 publications

References 52 publications

Effect of Substrate Surface Charges on Proton Conduction of Ultrathin Nafion Films

Effect of Substrate Surface Charges on Proton Conduction of Ultrathin Nafion Films

Surface-Modified Approach to Fabricate Nafion Membranes Covalently Bonded with Polyhedral Oligosilsesquioxane for Vanadium Redox Flow Batteries

Crosslinked ion diffusion inhibitors stabilize 3D/2D perovskite heterostructures for efficient and stable photovoltaics

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