Article
Chemistry, Physical
Chuan Long, Tuo Zhao, Lin Tian, Qiao Liu, Fanghui Wang, Zhihua Wang, Hong Zhu
Summary: By adjusting the polymer structure and alkyl chain modification, a high-performance and alkaline-stable anion exchange membrane with high ionic conductivity and excellent alkaline stability was successfully prepared. The membrane showed promising potential for application in anion exchange membrane fuel cells.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Lei Bai, Lingling Ma, Lv Li, Anran Zhang, Xiaoming Yan, Fengxiang Zhang, Gaohong He
Summary: The study reports the synthesis of ether-free polymers with different degrees of Y-shaped branching as AEM materials, which can increase the free volume of the AEM and thus help build ion channels with lower hydroxide ion transport resistance, improving the ionic conductivity.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Xingyu Wu, Nanjun Chen, Chuan Hu, Harm-Anton Klok, Young Moo Lee, Xile Hu
Summary: A fluorination strategy is reported to create a phase-separated morphological structure in poly(aryl piperidinium) anion-exchange membranes (AEMs). The fluorinated AEMs possess high conductivity and dimensional stability, as well as excellent mechanical and chemical stability. AEMFCs using these fluorinated AEMs achieve outstanding peak power density and remain stable over extended operation.
ADVANCED MATERIALS
(2023)
Article
Engineering, Chemical
Wanting Chen, Xiaozhou Wang, Tiantian Li, Xiaoming Yan, Xuemei Wu, Yang Zhang, Fan Zhang, Shouhai Zhang, Gaohong He
Summary: The novel amphiphilic cone-shaped inducer TQCX is proposed to create continuous ionic channels in AEM, which improves hydroxide conductivity of the composite membrane. Molecular dynamics simulation reveals the mechanism of inducing ionic clusters and constructing continuous channels by TQCX, achieving a 70% improvement in hydroxide conductivity at 3 wt% TQCX.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Polymer Science
Jiyong Choi, Kyungwhan Min, Yong-Hwan Mo, Sang-Beom Han, Tae-Hyun Kim
Summary: In this study, two types of anion exchange membranes (AEMs) containing crosslinked poly(phenylene oxide) (PPO) and poly(styrene ethylene butylene styrene) (SEBS), with and without triazole, were prepared. The addition of triazole improved the hydroxide-ion conductivity and mechanical/alkaline stability of the crosslinked membranes. X-ray diffraction (XRD) and atomic force microscopy (AFM) confirmed the increased phase separation caused by the triazole. Under water electrolysis conditions, a triazole-containing crosslinked PPO-SEBS membrane electrode assembly (MEA) exhibited higher current density compared to the triazole-free counterpart, due to the strong hydrogen bonding between triazole and water/OH-.
Article
Chemistry, Multidisciplinary
Sahng Hyuck Woo, Nak Jun Lee, Seung Ho Yook, Hee Soo Kim, Jieun Choi, Jae-Hun Kim, So Young Lee, Jong Hyun Jang, Sung Jong Yoo, Young-Gi Yoon, Jonghee Han, Hyoung-Juhn Kim
Summary: This research used an imaging technique to find new reasons for the reduced performance of polymer electrolyte fuel cells (PEFCs). H+ and OH- indicator sensors were attached to each electrode of a membrane electrode assembly and quantitative analysis of ion generation was conducted using digital microscopes. The proposed reactions in the fuel cell were confirmed and various reactions occurring in the electrode were examined.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Aiswarya K. Sidharthan, Shiny Joseph
Summary: A sustainable approach for synthesizing a sodium ion conducting cation exchange membrane was investigated in this study, addressing the issues of methanol permeability, ionic conductivity, and cost of the direct methanol fuel cell (DMFC). The use of polyvinyl alcohol (PVA) and sulfonated polyvinyl alcohol (SPVA)-montmorillonite clay (MMT) membranes in an alkaline medium improved the ionic conductivity and achieved a high peak power density in passive alkaline DMFC experiments.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Chemical
Hae Min Kim, Chuan Hu, Ho Hyun Wang, Jong Hyeong Park, Nanjun Chen, Young Moo Lee
Summary: This study reports the use of side-chain-type s-PDTP copolymers as ionomers and membranes for anion exchange membrane fuel cells (AEMFCs). These copolymers exhibit high alkaline stability, excellent micromorphology, and high OH- conductivity. The ionomers with moderate ion-exchange-capacity and rational water uptake show optimal AEMFC performance.
JOURNAL OF MEMBRANE SCIENCE
(2022)
Article
Polymer Science
Juanjuan Han, Chifeng Liu, Yuyang Lu, Xiumeng Zheng, Wanting Li, Yi Liu, Xiaohong Yang, Zhandong Ren, Meixue Hu, Li Xiao, Lin Zhuang
Summary: By constructing a semi-interpenetrating network structure, anion exchange membranes (AEMs) with balanced ion conductivity, mechanical strength, and alkali stability were created. The AEMs exhibited excellent comprehensive properties, making them promising candidates for anion exchange membrane fuel cells (AEMFCs).
Article
Chemistry, Physical
Tao Wang, Yu Zhao, Sheng Wang, Sheng Cheng, Shanzhong Yang, Haibing Wei, Yunsheng Ding
Summary: A major challenge in anion exchange membrane (AEM) fuel cells is the development of high-performing AEMs that meet alkaline stability, swelling resistance, and ion conductivity criteria simultaneously. Poly(biphenylene alkylene)-based membranes, specifically PBPA-6-QA, exhibit improved phase separation, suppressed water uptake, high ion conductivity, and improved alkaline stability. A single cell using PBPA-6-QA demonstrates a peak power density of 0.97 W cm-2 and remains stable at a constant current density of 0.2 A cm-2 for 90 hours without membrane degradation.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Yun Liu, Zhefei Pan, Oladapo Christopher Esan, Xiaoyu Huo, Xingyi Shi, Liang An
Summary: In this work, a new passive ammonia fuel cell prototype is designed and tested. The developed ammonia fuel cell features a passive supply of ammonia to the anode and an open cathode design. The performance and behavior of the fuel cell are investigated under different operating conditions, as well as the influence of structural parameters on mass transport and performance.
JOURNAL OF POWER SOURCES
(2023)
Article
Engineering, Chemical
Xixing Zhou, Lexuan Wu, Guangxu Zhang, Ruyu Li, Xu Hu, Xuanwei Chang, Yinghua Shen, Lei Liu, Nanwen Li
Summary: This study proposes a ternary copolymerization strategy to produce anion exchange membranes with high conductivity and chemical stability, utilizing comb-shaped copolymers with hydrophobic side chains attached to the backbone to stabilize the cation and achieve favorable morphology and performance.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Engineering, Chemical
Zhiru Liu, Li Bai, Shasha Miao, Chao Li, Ji Pan, Yu Jin, Dongrui Chu, Xiaomeng Chu, Lei Liu
Summary: Steric hindrance engineering plays a crucial role in the preparation of stable organic cations and durable polymeric anion exchange membrane materials. The study found that PPO-iP membranes, containing isopropyl-based QA cations, exhibited higher water uptake and hydroxide conductivity compared to PPO-nP and PPO-CH membranes. Additionally, PPO-CH membranes showed superior alkaline stability in chemical stability tests, while significant degradation was observed in PPO-iP and PPO-nP membranes. Overall, the highly conductive PPO-iP membrane demonstrated promising performance in alkaline fuel cells.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Engineering, Chemical
Xiaoqin Qiao, Xin Wang, Shibing Liu, Yinghua Shen, Nanwen Li
Summary: By designing and preparing polymer based on different spirocyclic ionenes, their stability in alkaline and fuel cells was investigated. Blending membranes using spirocyclic ionenes with phenyl or biphenyl rings showed good performance at high temperature, but unexpected degradation was observed in fuel cell device durability testing.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Engineering, Chemical
Andrit Allushi, Thanh Huong Pham, Patric Jannasch
Summary: This study focused on developing anion exchange membranes (AEMs) with high alkaline stability and hydroxide conductivity by functionalizing fluorene units with dual pairs of quaternary piperidinium cations. The AEMs with bisPip side chains demonstrated superior conductivity and alkaline stability compared to AEMs with monoPip cations per fluorene unit, highlighting the advantage of locally concentrating the cations in the polymer structure.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Engineering, Chemical
Rong Fu, Huangying Wang, Junying Yan, Ruirui Li, Chenxiao Jiang, Yaoming Wang, Tongwen Xu
Summary: Bipolar membrane electrodialysis (BMED) is a promising technique for upgrading traditional manufacturing procedures and achieving a circular economy. Researchers proposed a novel asymmetric bipolar membrane electrodialysis (ABMED) to regulate water splitting and ion migration, which showed comparable performance to BMED for acid/base production.
Article
Chemistry, Multidisciplinary
Kang Peng, Yuanyuan Li, Gonggen Tang, Yahua Liu, Zhengjin Yang, Tongwen Xu
Summary: In the development of aqueous organic redox flow batteries (AORFBs), anthraquinone derivatives (AQs) attract a great deal of attention as promising negative electrolytes. This study presents a solvation regulation strategy to extend the lifetime of 2,6-dihydroxyanthraquinone (DHAQ) electrolytes by incorporating tetramethylammonium cations (TMA(+)) to interfere with the solvation structure of DHAQ(2-)/DHAHQ(4-) anions. The strategy effectively reduces the capacity fade rate of DHAQ/K4Fe(CN)(6) cells caused by electrolyte decomposition.
ENERGY & ENVIRONMENTAL SCIENCE
(2023)
Article
Engineering, Chemical
Tingting Xu, Bin Wu, Yifan Li, Yanran Zhu, Fangmeng Sheng, Liang Ge, Xingya Li, Tongwen Xu
Summary: This study investigates the ion transport properties of different porous organic cage membranes. The window-to-window alignment of CC3 membranes leads to continuous channels, resulting in high ion permeability and selectivity. Compared to CC19, the hydrophobic channels of CC3 membranes facilitate fast ion transport by suppressing the hydrogen-bonding interaction. Tuning the surface charge of CC3 membranes increases the selectivity towards mono-/divalent cations. This work provides guidelines for the construction of efficient ion separation membranes.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Chengpeng Wei, Weisheng Yu, Yang Zhang, Fan Zhang, Ming Li, Xianhe Shen, Kaiyu Zhang, Xiaolin Ge, Liang Wu, Tongwen Xu
Summary: In this study, a novel AAEMs with pyrene-containing ether-free polymer backbones and rigid pyrene units was designed, which showed improved ion conductivity, chemical durability, and mechanical strength.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Weisheng Yu, Jianjun Zhang, Dong-Mei Huang, Xian Liang, Kaiyu Zhang, Yan Xu, Hongjun Zhang, Bangjiao Ye, Xiaolin Ge, Tongwen Xu, Liang Wu
Summary: We have demonstrated for the first time the effects of cis-trans conformation on the properties of anion exchange ionomers. The twisted cis-conformation with abundant subnanoscale free volume cavities enhances oxygen permeability and water adsorption. Additionally, the nonplanar conformation of the cis-ionomer reduces undesired absorption on Pt and Pt-Ru surfaces, thus improving the electrochemical performance of catalyst layers. The theoretical and electrochemical investigations provide mutual support for our proof-of-concept. The catalyst layer incorporating cis-ionomer shows significant increases in limiting current density and electrochemically active surface area (51% and 54% respectively). The H-2/O-2 single-cell peak power density of the cis-membrane electrode assembly (c-MEA) is increased by 56% (1.0 vs 0.64 W cm(-2)) compared to the t-MEA at 100% relative humidity (RH). Furthermore, the performance of c-MEA is particularly outstanding at low humidity (increased by 114% and 113% at 80% and 60% RH respectively).
ACS ENERGY LETTERS
(2023)
Article
Engineering, Environmental
Weisheng Yu, Chengpeng Wei, Kaiyu Zhang, Jianjun Zhang, Zijuan Ge, Xian Liang, Michael D. Guiver, Xiaolin Ge, Liang Wu, Tongwen Xu
Summary: In this study, a 4-sulfocalix[4]arene (4-SCA)-modified graphene oxide (GO) membrane was successfully fabricated, which exhibited high ion permeability and selectivity, as well as pH-responsiveness. The membrane preferentially transported potassium ions over radionuclide cations and showed an order of magnitude higher ion selectivity than the unmodified GO membrane. The improved selectivity resulted from the specific recognition between 4-SCA and radionuclide cations, which was responsive to the protonation/deprotonation transformation of 4-SCA. This biomimetic permselective GO membrane has potential applications in efficient nuclear wastewater treatment and contributes to a deeper understanding of biomimetic ion transport mechanisms.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Chemical
Xianhe Shen, Xian Liang, Yan Xu, Weisheng Yu, Qiuhua Li, Xiaolin Ge, Liang Wu, Tongwen Xu
Summary: This study reports the use of an antioxidant approach to grow a polypyrrole/manganese dioxide (PPy/MnOx) radical quenching layer on a highly proton conductive membrane surface to alleviate the oxidative degradation of the proton exchange membrane (PEM) in PEMFC. The modified PEM exhibits improved durability and slower open circuit voltage decay, without significantly impacting fuel cell performance. The resulting H2/O2 PEMFC single cell shows a promisingly high power density of over 900 mW cm-2 at 80 degrees C with 100% RH.
JOURNAL OF MEMBRANE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Peipei Zuo, Chunchun Ye, Zhongren Jiao, Jian Luo, Junkai Fang, Ulrich S. Schubert, Neil B. McKeown, T. Leo Liu, Zhengjin Yang, Tongwen Xu
Summary: The development of efficient ion-transport membranes is crucial for improving separation processes and electrochemical technologies. We have designed synthetic membranes with covalently bonded polymer frameworks that achieve near-frictionless ion flow through rigidly confined ion channels. These membranes have the potential to greatly enhance the performance of electrochemical devices and molecular separation.
Article
Engineering, Chemical
Tingting Xu, Yue Wang, Qian Chen, Yanran Zhu, Wenmin Li, Fangmeng Sheng, Liang Ge, Xingya Li, Tongwen Xu
Summary: Mixed matrix membranes (MMMs) are promising in ion separation due to their simple preparation process and potential industrial applications. By using a soluble porous organic cage (POC) as the filler, large scale and interfacial gap-free ionic polymer membranes can be fabricated with high ion flux and selectivity, as well as excellent stability during the electrodialysis process.
Article
Engineering, Chemical
Huangying Wang, Yang Wang, Junying Yan, Rong Fu, Baoying Wang, Chenxiao Jiang, Yaoming Wang, Tongwen Xu
Summary: By comparing the bipolar membrane electrodialysis (BMED) with the chlor-alkali process for sodium hydroxide production, it was found that BMED has lower energy consumption and less impact on global warming at moderate salt concentrations. Therefore, BMED is a promising and sustainable technique for base production.
Article
Engineering, Chemical
Bowen Hou, Rong Fu, Huangying Wang, Junying Yan, Ruirui Li, Baoying Wang, Chenxiao Jiang, Yaoming Wang, Tongwen Xu
Summary: Bipolar membrane crystallization (BMC) technology was proposed as a one-step conversion method for sulfate lithium into high-purity lithium hydroxide monohydrate crystals. By using continuous saturated feedstock in the salt compartment, Li2SO4 can be converted into 5+ mol/L LiOH at a high current density. The unique design of this technology allows the production of 99.9% LiOH & BULL; H2O, demonstrating its feasibility and competitiveness for waste lithium recovery.
Article
Engineering, Chemical
Kaiyu Zhang, WeiSheng Yu, Xiaolin Ge, Liang Wu, Tongwen Xu
Summary: In this study, the degradation barriers and mechanisms of heterocyclic quaternary ammoniums (QAs) were calculated using density functional theory (DFT). It was found that the chair conformation and ring structure of heterocyclic QAs inhibit Hoffman degradation and that methyl SN2 is the primary degradation pathway. Higher ring strain and electron-withdrawing groups negatively impact stability. The position of substituted methyl groups significantly affects molecule stability.
JOURNAL OF MEMBRANE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Wanjie Song, Xin Zhang, Cui Yang, Zhengjin Yang, Liang Wu, Xiaolin Ge, Tongwen Xu
Summary: Anion-exchange membranes that selectively transport OH(-), known as alkaline membranes, are increasingly important for electrochemical energy devices. This article discusses the research progress of alkaline membranes in terms of backbone structures, synthesis methods, and applications. The evaluation of synthesis methods and description of membrane stability enhancement strategies provide valuable insights for structural design. The future priority of addressing alkaline membranes from a scientific and engineering perspective is presented to accelerate the deployment of relevant technologies in alkaline media.
ACS CENTRAL SCIENCE
(2023)
Review
Materials Science, Multidisciplinary
Baoying Wang, Yaoming Wang, Tongwen Xu
Summary: Polymer inclusion membranes (PIMs) have attracted significant attention in metal separation and recovery due to their advantages of high selectivity, long service life, high stability, flexible design, and low cost. This review provides an overview of the preparation methods and composition of PIMs, discusses the relationship between the physicochemical properties of membrane components and the performance of PIMs, elucidates the metal transport mechanism, and summarizes the modification and separation intensification methods. The challenges and perspectives in the field of metal separation and recovery are also proposed.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Chemistry, Physical
Weisheng Yu, Xiaoqi Yang, Xian Liang, Yan Xu, Xianhe Shen, Xiaolin Ge, Liang Wu, Tongwen Xu
Summary: Reducing catalyst loading and humidity dependence is important for commercializing PEMFCs. The use of fluorine-free hydrocarbon membranes instead of perfluorinated sulfonic-acid PEMs can reduce manufacturing costs. The AS-MEA, fabricated using an all spraying method, shows superior performance compared to the CCS-MEA, particularly at low humidity and catalyst loading, and also exhibits good durability.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
