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Project titleDevelopment of composite proton-conducting membranes based on perfluorinated polymers and graphenes with intercalated fullerenes and nanodiamonds

AffiliationPetersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre "Kurchatov Institute",

Research area 03 - CHEMISTRY AND MATERIAL SCIENCES, 03-601 - Chemistry of new inorganic functional and nano-dimensional materials

Keywordsproton, membrane, polymer, fullerene, graphene, oxide, diamond, conductivity, structure

Annotation
Based on graphene oxide assemblies with grafted sulfonic acid groups (SO3H), proton-exchange membranes have been created. The assemblies bound through a perfluorinated copolymer (Nafion) served to form narrow channels (1; 5 nm) of ionic conduction by the Grottus hopping mechanism between sites on graphene oxide sheets. Sheets in assemblies were connected in two ways using C60 fullerene molecules and nanodiamonds with grafted hydrogen atoms, hydroxyls, and SO3H groups. To enhance and stabilize the conductive and mechanical properties, membrane films were prepared from a composite layer highly enriched in graphene oxide (90 wt %). Layer thickness equalization and parallel orientation of graphene assemblies along the layer were achieved using centrifugal acceleration during drying of the dispersion mixed with the copolymer deposited on the rotating polymer substrate. The composite layer was coated on both sides with a perfluorinated copolymer (precipitation of mixtures of a solution of a copolymer and a dispersion of graphene oxide in dimethylformamide). The electrical, physicochemical, and structural properties of layered anisotropic membranes have been studied at different degrees of moisture (0–100%) in comparison with the characteristics of similar isotropic composites containing up to 90% wt. graphene oxide. To achieve a greater effect, along with the Nafion material, a diamond-modified copolymer obtained in the process of emulsion polymerization of monomers in the presence of diamonds was used as a binder and material for the outer layers of anisotropic membranes. Fullerenes as linkers connecting sheets of graphene oxide ensured the formation of narrow channels (1 nm) with a calibrated size that is optimal for proton diffusion and does not change with variation in the degree of membrane moisture, which remains a problem for multilayer graphene oxide. As a result, in such membranes, the conditions for the minimum fuel crossover through the channels are implemented. The use of diamonds for bonding graphene oxide sheets made it possible to construct stable assemblies with calibrated gap width and a wavy surface due to the curvature of the graphene oxide surface when bonding with diamonds with a positive potential, which were attracted to a negatively charged graphene oxide (data on neutron scattering and synchrotron radiation in aqueous mixed oxide dispersions graphene and diamonds). Partially folding the graphene oxide film onto itself, the diamonds created channels for fast diffusion of protons, the binding energy of which decreased on the concave surface of graphene oxide. Electrophysical, physicochemical and structural properties of isotropic and anisotropic composite membranes with various graphene oxide assemblies were studied by impedance conductometry, electron and atomic force microscopy, IR and Raman spectroscopy, neutron scattering and synchrotron radiation in comparison with materials (Nafion, Aquivion). The results for the composite membranes tested in fuel cells with measurements of current-voltage characteristics are prepared for patenting and technological developments for hydrogen power.

Expected results
1. For the first time, prototypes of proton-exchange membranes with the effect of increased ionic conductivity (up to 1 order relative to serial materials) were created based on assemblies of sulfonated graphene oxide connected through a perfluorinated copolymer with a controlled size of two-dimensional diffusion channels through the intercalation of fullerenes and detonation nanodiamonds with a positive surface potential. 2. Two types of membrane films (thickness 30-50 μm) are obtained, investigated by electrophysical, physicochemical and structural methods - isotropic composites from assemblies of graphene oxide intercalated with fullerenes (nanodiamonds) and perfluorinated copolymer, and three-layer structures with a middle layer enriched with graphene up to 90% wt., and outer layers of a proton-conducting copolymer. 3. Samples of membrane films are certified: tested for strength and elastic properties, studied by impedance conductometry at various temperatures and humidification conditions, tested in hydrogen fuel cells with determination of current-voltage characteristics, stability of functional parameters, mechanical and chemical resistance, working life. 4. In the course of development, studies were carried out on the processes of formation of graphene oxide assemblies with fullerenes and nanodiamonds in the liquid phase, conditions were determined and regularities were established for the formation of multilayer assemblies (up to 10 layers) depending on the concentrations of the components, the polarity of the immersion media used, temperature, intensity and duration of exposure ultrasound. 5. Techniques for obtaining components of hybrid membranes have been developed: sulfonation of graphene oxide and nanodiamonds; obtaining a proton-conducting composite of a perfluorinated copolymer with nanodiamonds during the polymerization of monomers under conditions of interaction with nanodiamonds in a reaction mixture (emulsion). 6. Combined methods for studying the electrochemical, physicochemical and structural properties of polymer and carbon components and finished membranes have been developed using general physical and nuclear physics approaches to measurements (conductometry, IR and Raman spectroscopy, measurements of optical density in solutions, dynamic light scattering, scattering neutrons and synchrotron radiation, X-ray fluorescence analysis of the elemental composition, scanning and transmission electron microscopy, atomic force microscopy). 7. Based on the results of summarizing the data of the conducted research and development, reports were drawn up, materials for patenting were selected, reports at conferences and declared publications were prepared and produced, recommendations were developed for continuing work in the form of R&D and implementation in technology.

Annotation of the results obtained in 2023
In order to develop a new generation of composite membranes based on perfluorinated copolymers such as Nafion and Aquivion, a set of problems has been solved in the synthesis and modification of nano-sized fillers - C60 fullerenes in the original and hydroxylated forms, detonation nanodiamonds of calibrated size (4.5 nm) with various grafted functional groups (H, OH, COOH, F, SO3H) to set particle potentials (positive, negative) in an aqueous environment in order to regulate their hydrophilic (hydrophobic) properties in connection with further applications for intercalation into assemblies of graphene oxide prepared by special acid treatment with the addition of ionic groups (SO3H ) of the same type that membrane copolymer chains have. For the synthesis of copolymers, methods for obtaining and structural and physicochemical certification of monomers were developed, emulsion copolymerization modes were found to maintain a constant composition of the resulting macromolecules at a given equivalent mass to deep degrees of monomer conversion (above 90%). For the first time, the synthesis of copolymers through the interaction of monomers with hydrophilic nanodiamonds with a hydrogen-saturated surface was proposed and implemented. This made it possible to obtain a new membrane composite with a high content of diamonds (4.1 wt.%) without signs of their segregation in the polymer matrix. As a result, high proton conductivity of a polymer material reinforced with nanodiamonds was achieved, while providing the necessary mechanical (strength) properties for use in chemical energy sources. For the same purposes, conditions were found for obtaining graphene oxide dispersions, including sulfonated ones. There were performed the experiments to intercalate fullerenes into its assemblies for subsequent filling, reinforcement and strengthening of composite membranes. Diamonds reinforced with various grafted ionic groups were introduced into perfluorinated copolymers, which made it possible to increase proton conductivity, including at elevated temperatures, and the degree of hydration of membrane materials, stabilize the networks of their own ion channels in them and create hybrid conduction channels through the interaction of functional groups of copolymers and diamonds. Studies of the structure and electrochemical properties of these new composites using synchrotron and neutron scattering have made it possible to establish correlations between the structure and conductive properties of membranes, to reveal the mechanisms of incorporation of modifier particles into polymer matrices, to construct reasonable models for the ordering of copolymer chains into structures such as inverted cylindrical micelles with central ion channels, connected in a network through diamond faces with ionic groups creating a conductive interface with the polymer phase.

Publications

1. Lebedev V.T., Kulvelis Y.V., Shvidchenko A.V., Primachenko O.N., Odinokov, A.S., Marinenko E.A., Kuklin A.I., Ivankov O.I. Electrochemical Properties and Structure of Membranes from Perfluorinated Copolymers Modified with Nanodiamonds. Membranes, MDPI, Basel, Switzerland, 13, 850,1-42, Membranes, Licensee MDPI, Basel, Switzerland (year - 2023) https://doi.org/10.3390/membranes13110850

2. Shvidchenko A.V., Odinokov A.S., Primachenko O.N., Gofman I.V., Yevlampieva N.P., Marinenko E.A., Lebedev V.T., Kuklin A.I., Kulvelis Y.V. Shvidchenko, A.V.; Odinokov, A.S.; Primachenko, O.N.; Gofman, I.V.; Yevlampieva, N.P.; Marinenko, E.A.; Lebedev, V.T.; Kuklin, A.I.; Kulvelis, Y.V. Improving PFSA Membranes Using Sulfonated Nanodiamonds. Membranes. 2023, 13, 712 (1-17). MDPI, Т. 13, № 712, С. 1-17, Licensee MDPI, Basel, Switzerland. (year - 2023) https://doi.org/10.3390/membranes13080712

3. Kulvelis Yu.V., Lebedev V.T., Kuklin A.I., Primachenko O.N., Odinokov A.S., Shvidchenko A.V. Структура композитных протонопроводящих мембран с углеродными наполнителями Тезисы. Конференция по малоугловому рассеянию и рефлектометрии (МУРомец – 2023), 21-23 июня 2023 г., Гатчина, Россия, С.25.Тезисы. Конференция по малоугловому рассеянию и рефлектометрии (МУРомец – 2023), 21-23 июня 2023 г., Гатчина, Россия (year - 2023)

4. Kulvelis Yu.V., Lebedev V.T., Primachenko O.N., Odinokov A.S., Marinenko E.A., Shvidchenko A.V., Tudupova B.B., Kuular V.I., Kuklin A.I. Композитные протонопроводящие мембраны с наноуглеродными добавками Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия, С.210. Тезисы.Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия (year - 2023)

5. Kulvelis Yu.V., Lebedev V.T., Primachenko O.N., Odinokov A.S., Shvidchenko A.V., Tudupova B.B., Kuular V.I. Модификация механизма протонной проводимости мембран наноуглеродными добавками Тезисы, X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь, С.63. Тезисы.X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь (year - 2023)

6. Lebedev V.T., Kulvelis Yu.V., Primachenko O.N., Shvidchenko A.V., Kuklin A.I. СТРУКТУРА ПРОВОДЯЩИХ КАНАЛОВ И ДИНАМИКА ПРОТОНОВ В ИОНООБМЕННЫХ МЕМБРАНАХ ИЗ ПЕРФТОРИРОВАННЫХ СОПОЛИМЕРОВ Тезисы. Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия, С.182. Тезисы.Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия (2023 г.) (year - 2023)

7. Lebedev V.T., Kulvelis Yu.V., Primachenko O.N., Shvidchenko A.V., Kuklin A.I. Структура и проводимость модифицированных наноалмазами ионообменных полимерных мембран Тезисы. Конференция по малоугловому рассеянию и рефлектометрии (МУРомец – 2023), 21-23 июня 2023 г., Гатчина, Россия, С.27. Тезисы. Конференция по малоугловому рассеянию и рефлектометрии (МУРомец – 2023), 21-23 июня 2023 г., Гатчина, Россия (year - 2023)

8. Lebedev V.T., Kulvelis Yu.V., Remizov M.V., Kononova S.V., Primachenko O.N., Odinokov A.S., Marinenko E.A., Gofman I.V., Kuklin A.I. Структура и проводящие свойства перфторированных протон-обменных мембран с детонационными наноалмазами Тезисы, X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь, С.237. Тезисы. X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023) (year - 2023)

9. Lebedev V.T., Shakhov F.M., Vul A.Ya., Zakharov A.A., Zinoviev V.G., Orlova V.A., Fomin E.V. Синтез и люминесцентные свойства легированных европием алмазов Тезисы, X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь, С.64. Тезисы.X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь (year - 2023)

10. Remizov M.V., Kamanina N.V., Tomchuk A.V., Kulvelis Yu. V., Lebedev V.T. Нейтронная рефлектометрия покрытий из углеродных нанотрубок на металлооксидных подложках Тезисы. Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия, С.45. Тезисы.Конференция по использованию рассеяния нейтронов в исследовании конденсированных сред РНИКС-2023, 25-28 сентября 2023 г., г. Екатеринбург, Россия (year - 2023)

11. Tudupova B.B., Kuular V.I., Trofimuk A.D., Shvidchenko A.V., Kulvelis Yu.V., Lebedev V.T. Наноуглеродные графеновые комплексы для протонопроводящих мембран Тезисы, X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь, С.172. Тезисы, X МЕЖДУНАРОДНАЯ НАУЧНАЯ КОНФЕРЕНЦИЯ «АКТУАЛЬНЫЕ ПРОБЛЕМЫ ФИЗИКИ ТВЕРДОГО ТЕЛА» (APSSP-2023). 22-26 мая 2023 г. Минск. Беларусь (year - 2023)