Chinese Science Bulletin, Volume 64, Issue 2: 134-144(2019) https://doi.org/10.1360/N972018-00719

Advances in alkaline stable guanidinium based anion exchange membranes

More info
  • ReceivedJul 18, 2018
  • AcceptedSep 17, 2018
  • PublishedOct 16, 2018


Anion exchange membranes (AEMs) are solid polymer electrolytes that contain cationic groups covalently bound to or embedded in a polymer backbone. They act as key role of hydroxide conduction and separator between two electrodes in anion exchange membrane fuel cells (AEMFCs). To achieve high performance in AEMFCs, ideal AEMs should own high ion conductivity and good alkaline stability. Considering to the alkaline stability of AEMs, ionic groups play very important role in determining the overall stability for the AEMs apart from polymer backbones. To date, various ion conductive moieties have been investigated as new tethered ionic groups to replace conventional quaternary ammoniums (QAs) in AEMs because of the multiple degradation pathways under alkaline conditions including: (1) nucleophilic substitution (SN2), (2) Hoffmann elimination (E2), or (3) nitrogen ylide formation. Guanidiniums are found to be a kind of novel ionic groups for the application of AEMs. In the structure of guanidinium, the positive charge is uniformly distributed over the central carbon atom and three nitrogen atoms, leading to stabilized charge delocalization and good thermal and chemical stability. There are six substitutions distributed over three N atoms which can be easily tuned by a mature and feasible route. Additionally, the kinetics of hydrogen evolution/oxidation reaction (HER/HOR) and ORR catalyzed by Pt and carbon-based non precious metal could be greatly enhanced through using guanidiniums. Guanidinium cations can be introduced into the polymer backbone easily by the synthetic methods as follows: (1) halomethylation of a phenyl group and subsequent amination with pentalkylguanidine; (2) nucleophilic substitution of a Vilsmeier salt and a secondary amine; (3) activated fluoroamine reaction; (4) nucleophilic substitution of alkyl halid and guanidine to prepare guanidinium functional monomer; (5) polycondensation between guanidine hydrochloride and diamine. Recently, several types of guanidinium-functionalized AEMs have been explored including benzylic guanidinium AEMs, alkylic guanidinium AEMs and phenylic guanidinium AEMs. Some of the AEMs have been proven to possess excellent ion conductivity, and some have been used in AEMFCs and show good electrochemical performance. Considering to degradation mechanism of guanidinium, it can be concluded as a nucleophilic addition-elimination reaction: firstly the center C atom is attacked by OH- and an intermediate is obtained (addition reaction); then one of N atoms combines with the H atom and eliminates from the intermediate (elimination reaction); finally the degradation products urea and amine are formed. It is worth noting that the degradation process of guanidinium is evidently different from quaternary ammoniums. Their degradation reaction sites only occur at the central carbon atom rather than the benzyl carbon which indicate the promising stability for guanidinium. Though the stabilities of guanidiniums are under debate by now, the usability of guanidiniums as ionic group is still a topic worthy of study. On the one hand, almost all of the studies are confined to guanidiniums with methyl groups substituted at the N1 and N3 positions, hence comprehensive and systematic analysis of the structure-stability relationship of guanidinium cations in alkaline media is still rarely developed. On the other hand, the degradation process of guanidiniums is only speculated by a few studies in theoretical way, more specific experimental studies of this process are badly needed to prove it. Therefore, revealing the structure-stability relationship and the detailed degradation mechanism are vital to design alkaline stable guanidinums which can be applied to AEMs preparation in the future. In addition, the polymer backbone is also very important to improve the stability of guanidiniums based AEMs. More guanidiniums based AEMs with various structures should be designed and prepared. The ion conductivity, alkaline stability and cell performace should be assessed comprehensively to figure out the relationship between the structures and properties of AEMs, and finally the preparation of high performance anion exchange membranes can be achieved.

Funded by







[1] Carrette L, Friedrich K A, Stimming U. Fuel Cells-Fundamentals and Applications. Fuel Cells, 2001, 1: 5-39 CrossRef Google Scholar

[2] Borup R, Meyers J, Pivovar B, et al. Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chem Rev, 2007, 107: 3904-3951 CrossRef Google Scholar

[3] Merle G, Wessling M, Nijmeijer K. Anion exchange membranes for alkaline fuel cells: A review. J Membrane Sci, 2011, 377: 1-35 CrossRef Google Scholar

[4] Varcoe J R, Atanassov P, Dekel D R, et al. Anion-exchange membranes in electrochemical energy systems. Energy Environ Sci, 2014, 7: 3135-3191 CrossRef Google Scholar

[5] He G, Li Z, Zhao J, et al. Nanostructured ion-exchange membranes for fuel cells: Recent advances and perspectives. Adv Mater, 2015, 27: 5280-5295 CrossRef Google Scholar

[6] Li N, Leng Y, Hickner M A, et al. Highly stable, anion conductive, comb-shaped copolymers for alkaline fuel cells. J Am Chem Soc, 2013, 135: 10124-10133 CrossRef Google Scholar

[7] Pan J. A study of alkaline polymer electrolytes for fuel cell application (in Chinese). Doctor Dissertation. Wuhan: Wuhan University, 2012 [潘婧. 燃料电池用碱性聚合物电解质研究. 博士学位论文. 武汉: 武汉大学, 2012]. Google Scholar

[8] Li N, Guiver M D. Ion transport by nanochannels in ion-containing aromatic copolymers. Macromolecules, 2014, 47: 2175-2198 CrossRef ADS Google Scholar

[9] Dong X, Hou S, Mao H, et al. Novel hydrophilic-hydrophobic block copolymer based on cardo poly(arylene ether sulfone)s with bis -quaternary ammonium moieties for anion exchange membranes. J Membrane Sci, 2016, 518: 31-39 CrossRef Google Scholar

[10] Gu L, Sun Z, Yan F, et al. Progress of alkaline anion exchange membrane (in Chinese). J Funct Polym, 2016, 29: 153–162 [顾梁, 孙哲, 严锋, 等. 碱性阴离子交换聚合物膜研究进展. 功能高分子学报, 2016, 29: 153–162]. Google Scholar

[11] Dekel D R, Amar M, Willdorf S, et al. Effect of water on the stability of quaternary ammonium groups for anion exchange membrane fuel cell applications. Chem Mater, 2017, 29: 4425-4431 CrossRef Google Scholar

[12] Edson J B, Macomber C S, Pivovar B S, et al. Hydroxide based decomposition pathways of alkyltrimethylammonium cations. J Membrane Sci, 2012, 399-400: 49-59 CrossRef Google Scholar

[13] Marino M G, Kreuer K D. Alkaline stability of quaternary ammonium cations for alkaline fuel cell membranes and ionic liquids. ChemSusChem, 2015, 8: 513-523 CrossRef Google Scholar

[14] Lin B, Qiu L, Qiu B, et al. A soluble and conductive polyfluorene ionomer with pendant imidazolium groups for alkaline fuel cell applications. Macromolecules, 2011, 44: 9642-9649 CrossRef ADS Google Scholar

[15] Liu Y, Zhang B, Kinsinger C L, et al. Anion exchange membranes composed of a poly(2,6-dimethyl-1,4-phenylene oxide) random copolymer functionalized with a bulky phosphonium cation. J Membrane Sci, 2016, 506: 50-59 CrossRef Google Scholar

[16] Zhang B, Gu S, Wang J, et al. Tertiary sulfonium as a cationic functional group for hydroxide exchange Membranes. RSC Adv, 2012, 2: 12683-12685 CrossRef Google Scholar

[17] Zha Y, Disabb-Miller M L, Johnson Z D, et al. Metal-cation-based anion exchange membranes. J Am Chem Soc, 2012, 134: 4493-4496 CrossRef Google Scholar

[18] Wang J, Li S, Zhang S. Novel hydroxide-conducting polyelectrolyte composed of an poly(arylene ether sulfone) containing pendant quaternary guanidinium groups for alkaline fuel cell applications. Macromolecules, 2010, 43: 3890-3896 CrossRef ADS Google Scholar

[19] Duan H F, Zhang S B, Lin Y J, et al. Progress in the research of guanidinium ionic liquids (in Chinese). Chin J Org Chem, 2006, 10: 1335–1342 [段海峰, 张所波, 林英杰, 等. 胍盐离子液体的研究进展. 有机化学, 2006, 10: 1335–1342]. Google Scholar

[20] Konopka D, Johnson M A, Errico M, et al. Oxidation and oxygen reduction on polycrystalline platinum in aqueous tetramethylguanidine alkaline electrolyte. Electrochem Solid-State Lett, 2012, 15: B17 CrossRef Google Scholar

[21] Li S, Lin Y, Zhang S, et al. Guanidine/Pd(OAc)2-catalyzed room temperature Suzuki cross-coupling reaction in aqueous media under aerobic conditions. J Org Chem, 2006, 11: 4067–4072. Google Scholar

[22] Wang J H. Synthesis and properties of quaternized poly(arylene ether)s as anion exchange membranes (in Chinese). Doctor Dissertation. Changchun: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 2010 [王俊华. 聚芳醚基均相阴离子交换膜材料的制备与性质研究. 博士学位论文. 长春: 中国科学院长春应用化学研究所, 2010]. Google Scholar

[23] Lin X, Wu L, Liu Y, et al. Alkali resistant and conductive guanidinium-based anion-exchange membranes for alkaline polymer electrolyte fuel cells. J Power Sources, 2012, 217: 373-380 CrossRef Google Scholar

[24] Liu L, Li Q, Dai J, et al. A facile strategy for the synthesis of guanidinium-functionalized polymer as alkaline anion exchange membrane with improved alkaline stability. J Membrane Sci, 2014, 453: 52-60 CrossRef Google Scholar

[25] Zhang Q, Li S, Zhang S. A novel guanidinium grafted poly(aryl ether sulfone) for high-performance hydroxide exchange membranes. Chem Commun, 2010, 46: 7495-7497 CrossRef Google Scholar

[26] Kim D S, Labouriau A, Guiver M D, et al. Guanidinium-Functionalized Anion Exchange Polymer Electrolytes via Activated Fluorophenyl-Amine Reaction. Chem Mater, 2011, 23: 3795-3797 CrossRef Google Scholar

[27] Kim D S, Fujimoto C H, Hibbs M R, et al. Resonance stabilized perfluorinated ionomers for alkaline membrane fuel cells. Macromolecules, 2013, 46: 7826-7833 CrossRef ADS Google Scholar

[28] Xue B, Dong X, Li Y, et al. Synthesis of novel guanidinium-based anion-exchange membranes with controlled microblock structures. J Membrane Sci, 2017, 537: 151-159 CrossRef Google Scholar

[29] Qu C, Zhang H, Zhang F, et al. A high-performance anion exchange membrane based on bi-guanidinium bridged polysilsesquioxane for alkaline fuel cell application. J Mater Chem, 2012, 22: 8203-8207 CrossRef Google Scholar

[30] Chen Y, Tao Y, Wang J, et al. Comb-shaped guanidinium functionalized poly(ether sulfone)s for anion exchange membranes: Effects of the spacer types and lengths. J Polym Sci Part A-Polym Chem, 2017, 55: 1313-1321 CrossRef ADS Google Scholar

[31] Sajjad S D, Hong Y, Liu F. Synthesis of guanidinium-based anion exchange membranes and their stability assessment. Polym Adv Technol, 2014, 25: 108-116 CrossRef Google Scholar

[32] Sherazi T A, Zahoor S, Raza R, et al. Guanidine functionalized radiation induced grafted anion-exchange membranes for solid alkaline fuel cells. Int J Hydrogen Energy, 2015, 40: 786-796 CrossRef Google Scholar

[33] Cheng J, Yang G, Zhang K, et al. Guanidimidazole-quanternized and cross-linked alkaline polymer electrolyte membrane for fuel cell application. J Membrane Sci, 2016, 501: 100-108 CrossRef Google Scholar

[34] Mohanty A D, Bae C. Mechanistic analysis of ammonium cation stability for alkaline exchange membrane fuel cells. J Mater Chem A, 2014, 2: 17314-17320 CrossRef Google Scholar

[35] Li W, Wang S, Zhang X, et al. Degradation of guanidinium-functionalized anion exchange membrane during alkaline environment. Int J Hydrogen Energy, 2014, 39: 13710-13717 CrossRef Google Scholar

[36] Fukui K. Role of frontier orbitals in chemical reactions. Science, 1982, 218: 747-754 CrossRef ADS Google Scholar

[37] Pernpointner M, Hashmi A S K. Fully relativistic, comparative investigation of gold and platinum alkyne complexes of relevance for the catalysis of nucleophilic additions to alkynes. J Chem Theor Comput, 2009, 5: 2717-2725 CrossRef Google Scholar

Copyright 2020 Science China Press Co., Ltd. 《中国科学》杂志社有限责任公司 版权所有