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Hydroxide exchange membranes (HEMs) have attracted extensive attention in energy-related fields, such as fuel cells and water electrolysis, primarily due to their suitability for alkaline environments. However, the practical application of membranes is hindered significantly by their limited conductivity. In this study, a series of amphoteric metal ion-coordinated chitosan (CTS-AM) membranes with enhanced hydroxide ion conductivity are reported. The CTS-AM membranes are prepared using a simple soaking-drying method, exhibiting excellent mechanical strength and thermal stability due to the strong coordination bonds between amphoteric metal ions and chitosan chains. To the best of our knowledge, the Zn coordinated chitosan membrane achieved the highest-ever reported hydroxide ion conductivity of 82.0 ± 5.4 mS cm at 25 °C and 100% RH, with the value increasing to 301.0 ± 6.7 mS cm at operating temperature (80 °C) and 100% RH. Through combined structural analysis and theoretical calculations, we propose that the formation of nanochannels and the lowered barrier for electron transfer are responsible for the high hydroxide ion conductivities of CTS-AM membranes. This study presents a viable approach to the design and fabrication of high-performance HEMs for energy storage devices and other applications.
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http://dx.doi.org/10.1002/asia.202500413 | DOI Listing |
Research (Wash D C)
August 2025
Materials Science, Energy and Nanoengineering (MSN) Department, University Mohammed VI Polytechnic, Ben Guerir, Morocco.
Water electrolysis is a key industrial process for producing green hydrogen. To avoid the use of noble metals and fluorinated polymer membranes, liquid water electrolysis is often carried out in alkaline conditions. It is common to distinguish between 3 processes: alkaline electrolysis at high electrolyte concentrations (≥7 M) with porous membranes, alkaline electrolysis at high electrolyte concentrations (≥7 M) with ion-solvating membranes, and alkaline electrolysis at moderate electrolyte concentrations (<2 M) with anion-exchange membranes.
View Article and Find Full Text PDFBiomolecules
July 2025
Key Laboratory of Chemo/Biosensing and Detection of Xuchang, Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Henan Joint International Research Laboratory of Nanomaterials for Energy and Catalysis, College of Chemical and Materials Engineering, Xuchang Uni
In the context of critical challenges in curcumin-modified polyurethane synthesis-including limited curcumin bioavailability and suboptimal biodegradability/biocompatibility-a novel polyurethane material (Cur-PU) with good mechanical, shape memory, pH-responsive, and biocompatibility was synthesized via a one-pot, two-step synthetic protocol in which HO-PCL-OH served as the soft segment and curcumin was employed as the chain extender. The experimental results demonstrate that with the increase in Cur units, the crystallinity of the Cur-PU material decreases from 32.6% to 5.
View Article and Find Full Text PDFMembranes (Basel)
July 2025
Department of Chemical and Biomolecular Engineering, Universidad de Cantabria, A. Los Castros s/n, 39005 Santander, Spain.
The demand for anion exchange membranes (AEMs) is growing due to their applications in water electrolysis, CO reduction conversion and fuel cells, as well as water treatment, driven by the increasing energy demand and the need for a sustainable future. However, current AEMs still face challenges, such as insufficient permeability and stability in strongly acidic or alkaline media, which limit their durability and the sustainability of membrane fabrication. In this study, polyvinyl alcohol (PVA) and chitosan (CS) biopolymers are selected for membrane preparation.
View Article and Find Full Text PDFBioresour Technol
August 2025
Qingdao New Energy Shandong Laboratory, Qingdao Key Laboratory of Functional Membrane Material and Membrane Technology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China.
The recovery of volatile fatty acids (VFAs) from waste-activated sludge (WAS) is crucial for sustainable bio-based systems; however, low substrate degradability limits this process. This study combines heat-alkali pretreatment, NaSiO buffering for pH stabilization, and electrodialysis with bipolar membranes (EDBM) to enhance VFAs production and alkali recovery. Semi-continuous fermentation with ultrafiltration pretreatment achieved a maximum VFAs yield of 8.
View Article and Find Full Text PDFSmall
August 2025
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117576, Singapore.
In recent years, anion exchange membranes (AEMs) have garnered considerable attention due to their pivotal roles in energy applications, including fuel cells, batteries, and electrolyzers. However, enhancing hydroxide (OH) ion conductivity in these membranes remains challenging. Here, the design of covalent organic framework (COF) membranes with tailored hydrogen bond networks is reported to facilitate rapid OH ion transport.
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