Silk nanofibril as nanobinder for preparing COF nanosheet-based proton exchange membrane

Li, Ping; Zhang, Ningxin; Li, Xuan; Tang, Shaokun

doi:10.1016/j.gee.2022.05.008

Cited by 19 publications

(11 citation statements)

References 51 publications

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“…Meanwhile, the ∼20 μm thick poly 0.02 COM exhibits better flexibility (inset photographs of Figures a and b). The EDS elemental mapping indicates that the HPEI molecules are uniformly dispersed in poly 0.02 COM (Figure c) . These results indicate that the interparticle interactions between COF particles are enhanced by the flexible HPEI.…”

Section: Resultsmentioning

confidence: 81%

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Free-Standing Polymer Covalent Organic Framework Membrane with High Proton Conductivity and Structure Stability

Wang,

Ren

et al. 2023

ACS Appl. Polym. Mater.

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The two-dimensional covalent organic framework (COF) with continuous and stable pores as well as tunable functional groups is considered as promising proton exchange membrane (PEM) material. However, due to the strong rigidity and inferior processability of COFs, it still remains challenging to prepare a self-standing and robust membrane. Herein, self-standing and robust thin COF membranes (20 μm in thickness) were fabricated through the in situ involvement of hyperbranched polyethylenimine (HPEI). The HPEI cross-links the adjacent COF particles and enhances the interactions among them. The involvement of HPEI enables polyCOM to have excellent structure ability, mechanical property, and proton conduction ability. As a result, poly 0.2 COM obtains a high water uptake of 72.3% at 80 °C (vs 49.11% for Nafion) with a negligible swelling ratio of 1.5%. In addition, the tensile strength of poly 0.2 COM reaches 45.4 MPa, 2.4 times higher than that of the TpPa-SO 3 H membrane (13.26 MPa). Importantly, polyCOM shows high proton conductivities of 223 and 35 mS cm −1 under saturated humidity and a low relative humidity (RH) of 30%, respectively, far exceeding those of the commercial Nafion membrane (80 and 5.5 mS cm −1 ). Moreover, poly 0.02 COM acquires a remarkable power density of 111.1 mW cm −2 and a current density of 664 mA cm −2 at 80 °C and 40% RH.

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Section: Resultsmentioning

confidence: 81%

“…The EDS elemental mapping indicates that the HPEI molecules are uniformly dispersed in poly 0.02 COM (Figure 2c). 35 These results indicate that the interparticle interactions between COF particles are enhanced by the flexible HPEI. The interactions between HPEI molecules and COF particles were further explored by XPS.…”

Section: ■ Introductionmentioning

confidence: 83%

Free-Standing Polymer Covalent Organic Framework Membrane with High Proton Conductivity and Structure Stability

Wang,

Ren

et al. 2023

ACS Appl. Polym. Mater.

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“…As presented in Figure 4e, the S 2p demonstrates two peaks of SO 3 H and SO 3 − , centered at 168.3 and 167.0 eV, respectively. [ 24,31 ] The peak area ratio between SO 3 − and SO 3 H for pure CON‐2(SO 3 H) membrane is 0.2, while the ratio value increases to 0.5 for CON‐2(SO 3 H)@CS‐3 membrane, revealing that the abovementioned electrostatic interactions can promote deprotonation process of SO 3 H groups in CON‐2(SO 3 H). Further evidence for this electrostatic interactions comes from the Raman spectra results in Figure 4f.…”

Section: Resultsmentioning

confidence: 98%

“…To alleviate the above issues, in previous work, we have prepared sulfonated CONs and verified that these sulfonated CONs can be effectively connected by silk nanofibrils (from natural silkworm cocoon) through physical entanglement and hydrogen bond interactions to obtain membranes with desired mechanical and conductive performance. [24] Here, we report the synthesis of dual-sulfonate CONs (denoted as CON-2(SO 3 H)) featuring nanometer-scale thickness, micrometer-scale lateral size, decent crystallinity and high-density SO 3 H groups through condensation of amine monomer bearing dual SO 3 H groups with aldehyde monomer at the interface between water and octanoic acid. Then, a natural polymer, chitosan (CS) is utilized as the linker to assemble CON-2(SO 3 H) into dense CON-2(SO 3 H)@CS membrane with high CON-2(SO 3 H) content by filtration.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chitosan‐Linked Dual‐Sulfonate COF Nanosheet Proton Exchange Membrane with High Robustness and Conductivity

et al. 2023

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Abstract2D materials that can provide long‐range ordered channels in thin‐film form are highly desirable for proton exchange membranes (PEMs). Covalent organic framework nanosheets (CONs) are promising 2D materials possessing intrinsic porosity and high processability. However, the potential of CONs in PEMs is limited by loose sheet stacking and interfacial grain boundary, which lead to unsatisfied mechanical property and discontinuous conduction pathway. Herein, chitosan (CS), a natural polymer with rich NH2 groups, is designed as the linker of dual‐sulfonate CONs (CON‐2(SO3H)) to obtain CON‐2(SO3H)‐based membrane. Ultrathin CON‐2(SO3H) with high crystallinity and large lateral size is synthesized at water–octanoic acid interface. The high flexibility of CS chains and their electrostatic interactions with SO3H groups of CON‐2(SO3H) enable effective connection of CON‐2(SO3H), thus endowing membrane dense structure and exceptional stability. The stacked CON‐2(SO3H) constructs regular hydrophilic nanochannels containing high‐density SO3H groups, and the electrostatic interactions between CON‐2(SO3H) and CS form interfacial acid–base pairs transfer channels. Consequently, CON‐2(SO3H)@CS membrane simultaneously achieves superior proton conductivity of 353 mS cm−1 (under 80 °C hydrated condition) and tensile strength of 95 MPa. This work highlights the advantages of proton‐conducting porous CON‐2(SO3H) in advanced PEMs and paves a way in fabricating robust CON‐based membranes for various applications.

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Subnanometer Nanowire‐Reinforced Construction of COF‐Based Membranes with Engineering Biomimetic Texture for Efficient and Stable Proton Conduction

Zhu,

Zhang,

Ren

et al. 2023

Adv Funct Materials

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Achieving rapid ion transport through nanochannels is essential for both biological and artificial membrane systems. Covalent organic frameworks (COFs) with well‐defined nanostructures hold great promise for addressing the above challenge. However, due to the limited processability and inadequate interlamellar interaction of COF materials, it is extremely difficult to integrate them to prepare high‐performance proton conductors. Herein, inspired by the ingenious bio‐adhesion strategy in nature, ultrafast proton conduction is achieved by taking advantage of COF membranes where TP‐COF nanosheets are linked by subnanometer nanowires/lignocellulosic nanofibrils composites (SNWs/LCNFs) through electrostatic and π‐π interactions to form an ordered and robust structure. Notably, the synthesized SNWs exhibited impressive proton conductivity and adhesion capacity due to their inbuilt phosphotungstic acid (HPW) molecules and multidimensional interactions. Therefore, attributed to the synergistic contribution of TP‐COFs and SNWs, the composite membrane achieves ultrahigh proton conductivity (0.395 S cm−1 at 80 °C and 100% RH), superior mechanical property (109.8 MPa), exceptional fuel cell performance (71.6 mW cm−2), and superior operational stability (OCV decay rate is about 1.5 mV h−1), demonstrating outstanding competitiveness. More importantly, the proposed design concept has the potential to be applied in membranes for various electrochemical devices and molecular separations.

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Silk nanofibril as nanobinder for preparing COF nanosheet-based proton exchange membrane

Cited by 19 publications

References 51 publications

Free-Standing Polymer Covalent Organic Framework Membrane with High Proton Conductivity and Structure Stability

Free-Standing Polymer Covalent Organic Framework Membrane with High Proton Conductivity and Structure Stability

Chitosan‐Linked Dual‐Sulfonate COF Nanosheet Proton Exchange Membrane with High Robustness and Conductivity

Subnanometer Nanowire‐Reinforced Construction of COF‐Based Membranes with Engineering Biomimetic Texture for Efficient and Stable Proton Conduction

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