A Review on Applications and Challenges of Fullerenes in Proton Exchange Membranes

Abstract

Clean energy devices have the potential to change the world and avoid future energy crises. The development of new energy-efficient technologies helps reduce our dependence on limited fossil fuel resources. Hydrogen energy is the key to achieving clean energy transition goals. Proton exchange membrane fuel cells play a critical role. Research and development of new high-tech proton exchange membranes (PEMs) provide new horizons for the development of hydrogen energy. The use of carbon nanomaterials to improve PEM efficiency is one of the modern trends. The modification of modern membranes with fullerenes and their derivatives is an innovative strategy for increasing proton conductivity. This paper discusses the key principles of proton transport in PEMs modified with individual fullerenols, sulfofullerenes, carboxylated fullerenes, phosphofullerenes, and cianohydrofullerenes. The introduction of fullerene nanoparticles into polymer PEM induces an improvement in key properties. Summary information covers existing research on the use of fullerenes as nanoscale modifiers of proton-conducting materials. This review will help researchers to surpass the achieved results in the field of modern proton-conducting materials and stimulate the development of hydrogen energy.

Keywords

composite proton exchange membranes / fuel cells / fullerenes / functionalized fullerenes

References

[1] Y.-H. Chen, C.-Y. Chen, and S.-C. Lee, “Technology Forecasting and Patent Strategy of Hydrogen Energy and Fuel Cell Technologies,” International Journal of Hydrogen Energy 36, no. 12 (2011): 6957–6969.

[2] I. Ozsari, “Trend Analysis and Evaluation of Hydrogen Energy and Hydrogen Storage Research,” Energy Storage 5, no. 6 (2023): e471.

[3] G. W. Crabtree and M. S. Dresselhaus, “The Hydrogen Fuel Alternative,” MRS Bulletin 33, no. 4 (2008): 421–428.

[4] M. Yue, H. Lambert, E. Pahon, R. Roche, S. Jemei, and D. Hissel, “Hydrogen Energy Systems: A Critical Review of Technologies, Applications, Trends and Challenges,” Renewable and Sustainable Energy Reviews 146 (2021): 111180.

[5] R. Asghar, S. Hassan, and Y. Yaqoob, “A Comprehensive Overview of Wet Chemistry Methodologies and Their Application in the Fabrication of Materials for PEM Fuel Cell,” International Journal of Hydrogen Energy 58 (2024): 1190–1203.

[6] N. Baig, I. Kammakakam, and W. Falath, “Nanomaterials: A Review of Synthesis Methods, Properties, Recent Progress, and Challenges,” Materials Advances 2, no. 6 (2021): 1821–1871.

[7] A. Ka'ki, A. Al-Othman, M. Tawalbeh, et al., “Green Materials for Fuel Cells,” Comprehensive Green Materials (Elsevier, 2025).

[8] C. Nicholson, Cruickshank, and Carlisle, “IV Experiments in Galvanic Electricity,” Philosophical Magazine 7, no. 28 (1800): 337–347.

[9] K. R. Williams, “Francis Thomas Bacon, 21 December 1904–24 May 1992,” Biographical Memoirs of Fellows of the Royal Society 39 (1994): 1–18.

[10] A. Parekh, “Recent Developments of Proton Exchange Membranes for PEMFC: A Review,” Frontiers in Energy Research 10 (2022): 956132.

[11] A. J. Jacobson, “Materials for Solid Oxide Fuel Cells,” Chemistry of Materials 22, no. 3 (2010): 660–674.

[12] A. R. Jha, “Fuel Cell Technology.” Next-Generation Batteries and Fuel Cells for Commercial, Military, and Space Applications (CRC Press, 2016).

[13] I. Staffell, “Stationary Fuel Cells – Residential Applications,” Fuel Cells: Data, Facts and Figures (Wiley, 2016).

[14] W. R. W. Daud, R. E. Rosli, E. H. Majlan, S. Hamid, R. Mohamed, and T. Husaini, “PEM Fuel Cell System Control: A Review,” Renewable Energy 113 (2017): 620–638.

[15] V. Mehta and J. S. Cooper, “Review and Analysis of PEM Fuel Cell Design and Manufacturing,” Journal of Power Sources 114, no. 1 (2003): 32–53.

[16] C. R. Wang, J. M. Stansberry, R. Mukundan, et al., “Proton Exchange Membrane (PEM) Water Electrolysis: Cell-Level Considerations for Gigawatt-Scale Deployment,” Chemical Reviews 125, no. 3 (2025): 1257–1302.

[17] Y. Song, C. Wang, Y. Jiang, et al., “Tailoring Ultrashort Inter-Fullerene Spacing in a Continuous Fullerene Stacking Array to Enhance Electron Transport for Boosting Solar-Driven Hydrogen Production,” Carbon Energy 7, no. 7 (2025): e70000.

[18] V. Georgakilas, J. A. Perman, J. Tucek, and R. Zboril, “Broad Family of Carbon Nanoallotropes: Classification, Chemistry, and Applications of Fullerenes, Carbon Dots, Nanotubes, Graphene, Nanodiamonds, and Combined Superstructures,” Chemical Reviews 115, no. 11 (2015): 4744–4822.

[19] Z. Chai, C. Wang, H. Zhang, et al., “Nafion–Carbon Nanocomposite Membranes Prepared Using Hydrothermal Carbonization for Proton-Exchange-Membrane Fuel Cells,” Advanced Functional Materials 20, no. 24 (2010): 4394–4399.

[20] G. Rambabu, S. D. Bhat, and F. M. L. Figueiredo, “Carbon Nanocomposite Membrane Electrolytes for Direct Methanol Fuel Cells—A Concise Review,” Nanomaterials 9, no. 9 (2019): 1292.

[21] R. Foroutan, S. J. Peighambardoust, R. Mohammadi, S. H. Peighambardoust, and B. Ramavandi, “The Potential of Biochar Derived From Banana Peel/Fe₃O₄/ZIF-67@K₂CO₃ as Magnetic Nanocatalyst for Biodiesel Production From Waste Cooking Oils,” Results in Engineering 22 (2024): 102005.

[22] S. J. Peighambardoust, S. Rowshanzamir, M. G. Hosseini, and M. Yazdanpour, “Self-Humidifying Nanocomposite Membranes Based on Sulfonated Poly(Ether Ether Ketone) and Heteropolyacid Supported Pt Catalyst for Fuel Cells,” International Journal of Hydrogen Energy 36, no. 17 (2011): 10940–10957.

[23] S. Rowshanzamir, S. J. Peighambardoust, M. J. Parnian, G. R. Amirkhanlou, and A. Rahnavard, “Effect of Pt-Cs_2.5H_0.5PW₁₂O₄₀ Catalyst Addition on Durability of Self-Humidifying Nanocomposite Membranes Based on Sulfonated Poly (Ether Ether Ketone) for Proton Exchange Membrane Fuel Cell Applications,” International Journal of Hydrogen Energy 40, no. 1 (2015): 549–560.

[24] M. R. Karim, M. S. Islam, K. Hatakeyama, et al., “Effect of Interlayer Distance and Oxygen Content on Proton Conductivity of Graphite Oxide,” Journal of Physical Chemistry C 120, no. 38 (2016): 21976–21982.

[25] A. V. Penkova, S. F. Acquah, L. B. Piotrovskiy, D. A. Markelov, A. S. Semisalova, and H. W. Kroto, “Fullerene Derivatives as Nano-Additives in Polymer Composites,” Russian Chemical Reviews 86, no. 6 (2017): 530–566.

[26] B. C. Thompson and J. M. J. Fréchet, “Polymer–Fullerene Composite Solar Cells,” Angewandte Chemie International Edition 47, no. 1 (2008): 58–77.

[27] L. Chen, Y. Ren, F. Fan, et al., “Artificial Frameworks Towards Ion-Channel Construction in Proton Exchange Membranes,” Journal of Power Sources 574 (2023): 233081.

[28] C. Yin, J. Li, Y. Zhou, H. Zhang, P. Fang, and C. He, “Enhancement in Proton Conductivity and Thermal Stability in Nafion Membranes Induced by Incorporation of Sulfonated Carbon Nanotubes,” ACS Applied Materials & Interfaces 10, no. 16 (2018): 14026–14035.

[29] R. Taherian and A. Kausar, “Polymer/fullerene Nanocomposites for Fuel Cells,” Polymer/Fullerene Nanocomposites (Elsevier, 2023).

[30] E. Abouzari-Lotf, M. Etesami, and M. M. Nasef, “Carbon-Based Nanocomposite Proton Exchange Membranes for Fuel Cells,” Carbon-Based Polymer Nanocomposites for Environmental and Energy Applications (Elsevier, 2018).

[31] R. Keçili, S. Büyüktiryaki, and C. M. Hussain, “Membrane Applications of Nanomaterials.” Handbook of Nanomaterials in Analytical Chemistry (Elsevier, 2020).

[32] Y. Yuan and J. Lu, “Demanding Energy From Carbon,” Carbon Energy 1, no. 1 (2019): 8–12.

[33] R. Paul, Q. Dai, C. Hu, and L. Dai, “Ten years of Carbon-Based Metal-Free Electrocatalysts,” Carbon Energy 1, no. 1 (2019): 19–31.

[34] T. Kuila, S. Bose, A. K. Mishra, P. Khanra, N. H. Kim, and J. H. Lee, “Chemical Functionalization of Graphene and Its Applications,” Progress in Materials Science 57, no. 7 (2012): 1061–1105.

[35] L. Meng, C. Fu, and Q. Lu, “Advanced Technology for Functionalization of Carbon Nanotubes,” Progress in Natural Science 19, no. 7 (2009): 801–810.

[36] M. Liu, Y. Han, Y. Cheng, X. Zhao, and H. Zheng, “Exploring Exohedral Functionalization of Fullerene With Automation and Neural Network Potential,” Carbon 213 (2023): 118180.

[37] H. W. Kroto, J. R. Heath, S. C. O'Brien, R. F. Curl, and R. E. Smalley, “C₆₀: Buckminsterfullerene,” Nature 318, no. 6042 (1985): 162–163.

[38] N. I. Alekseev, B. M. Filippov, I. V. Basargin, and A. I. Sedov, “Investigation of Semicommercial Arc Plants for Fullerene-Production,” Journal of Engineering Physics and Thermophysics 84, no. 5 (2011): 1087–1098.

[39] M. Mojica, J. A. Alonso, and F. Méndez, “Synthesis of Fullerenes,” Journal of Physical Organic Chemistry 26, no. 7 (2013): 526–539.

[40] F. Piccinno, F. Gottschalk, S. Seeger, and B. Nowack, “Industrial Production Quantities and Uses of Ten Engineered Nanomaterials in Europe and the World,” Journal of Nanoparticle Research 14, no. 9 (2012): 1109, https://doi.org/10.1007/s11051-012-1109-9.

[41] R. J. Aitken, M. Q. Chaudhry, A. B. A. Boxall, and M. Hull, “Manufacture and Use of Nanomaterials: Current Status in the UK and Global Trends,” Occupational Medicine 56, no. 5 (2006): 300–306.

[42] R. Gao, Q. Dai, F. Du, D. Yan, and L. Dai, “C₆₀-Adsorbed Single-Walled Carbon Nanotubes as Metal-Free, pH-Universal, and Multifunctional Catalysts for Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution,” Journal of the American Chemical Society 141, no. 29 (2019): 11658–11666.

[43] F. Gao, G.-L. Zhao, S. Yang, and J. J. Spivey, “Nitrogen-Doped Fullerene as a Potential Catalyst for Hydrogen Fuel Cells,” Journal of the American Chemical Society 135, no. 9 (2013): 3315–3318.

[44] B. Gao and G. Chen, “CO Oxidization Catalyzed by B, N, and Their Co-Doped Fullerenes: A First-Principles Investigation,” RSC Advances 9, no. 38 (2019): 21626–21636.

[45] S. Liu, F.-W. Gao, H.-L. Xu, and Z.-M. Su, “Transition Metals Doped Fullerenes: Structures – NLO Property Relationships,” Molecular Physics 117, no. 6 (2019): 705–711.

[46] A. F. Ridassepri, Y. Umejima, and J. Nakamura, “B-Doped Fullerene as a Potential Metal-Free Catalyst Material for CO Reduction Reaction,” Journal of Physical Chemistry C 128, no. 23 (2024): 9513–9519.

[47] M. M. Radhi and E. A. J. Al-Mulla, “Copolymer Electrode Self-Modified With Fullerene C₆₀,” Epitoanyag - Journal of Silicate Based and Composite Materials 70, no. 5 (2018): 134–139.

[48] H. A. Tahini, X. Tan, and S. C. Smith, “Unraveling the Factors Behind the Efficiency of Hydrogen Evolution in Endohedrally Doped C₆₀ Structures via Ab Initio Calculations and Insights From Machine Learning Models,” Advanced Theory and Simulations 2, no. 3 (2019): 1800202.

[49] S. H. Noh, C. Kwon, J. Hwang, et al., “Self-Assembled Nitrogen-Doped Fullerenes and Their Catalysis for Fuel Cell and Rechargeable Metal–Air Battery Applications,” Nanoscale 9, no. 22 (2017): 7373–7379.

[50] M. C. Padole and P. A. Deshpande, “Structural and Electronic Properties of Chemically Modified Fullerenes,” Molecular Simulation 45, no. 8 (2019): 623–635.

[51] M. A. Ahsan, T. He, K. Eid, et al., “Tuning the Intermolecular Electron Transfer of Low-Dimensional and Metal-Free BCN/C₆₀ Electrocatalysts via Interfacial Defects for Efficient Hydrogen and Oxygen Electrochemistry,” Journal of the American Chemical Society 143, no. 2 (2021): 1203–1215.

[52] I. H. Lin, Y. H. Lu, and H. T. Chen, “Nitrogen-Doped C₆₀ as a Robust Catalyst for CO Oxidation,” Journal of Computational Chemistry 38, no. 23 (2017): 2041–2046.

[53] B. Chai, T. Peng, X. Zhang, J. Mao, K. Li, and X. Zhang, “Synthesis of C₆₀-Decorated SWCNTs (C₆₀-d-CNTs) and Its TiO₂-Based Nanocomposite With Enhanced Photocatalytic Activity for Hydrogen Production,” Dalton Transactions 42, no. 10 (2013): 3402–3409.

[54] S. Scaravonati, G. Magnani, M. Gaboardi, G. Allodi, M. Riccò, and D. Pontiroli, “Electrochemical Intercalation of Fullerene and Hydrofullerene With Sodium,” Carbon 130 (2018): 11–18.

[55] X. Yang, J. Peng, L. Zhao, et al., “Insights on Advanced G-C₃N₄ in Energy Storage: Applications, Challenges, and Future,” Carbon Energy 6, no. 4 (2024): e490.

[56] A. P. Saab, G. D. Stucky, S. Passerini, and W. H. Smyrl, “Ionic Conductivity of C₆₀-Based Solid Electrolyte,” Fullerene Science and Technology 6, no. 2 (1998): 227–242.

[57] P. W. Stephens, L. Mihaly, P. L. Lee, et al., “Structure of Single-Phase Superconducting K₃C₆₀,” Nature 351, no. 6328 (1991): 632–634.

[58] Q. Xie, E. Perez-Cordero, and L. Echegoyen, “Electrochemical Detection of C₆₀⁶⁻ and C₇₀⁶⁻: Enhanced Stability of Fullerides in Solution,” Journal of the American Chemical Society 114, no. 10 (1992): 3978–3980.

[59] Y. Ohsawa and T. Saji, “Electrochemical Detection of C₆₀⁶⁻ at Low Temperature,” Journal of the Chemical Society, Chemical Communications no. 10 (1992): 781, https://doi.org/10.1039/c39920000781.

[60] F. Zhou, C. Jehoulet, and A. J. Bard, “Reduction and Electrochemistry of Fullerene C₆₀ in Liquid Ammonia,” Journal of the American Chemical Society 114, no. 27 (1992): 11004–11006.

[61] Y. Zhang, Q. Zhang, and G. Chen, “Carbon and Carbon Composites for Thermoelectric Applications,” Carbon Energy 2, no. 3 (2020): 408–436.

[62] Y. Liu, S. Roy, S. Sarkar, J. Xu, Y. Zhao, and J. Zhang, “A Review of Carbon Dots and Their Composite Materials for Electrochemical Energy Technologies,” Carbon Energy 3, no. 5 (2021): 795–826.

[63] N. A. A. Qasem, “A Recent Overview of Proton Exchange Membrane Fuel Cells: Fundamentals, Applications, and Advances,” Applied Thermal Engineering 252 (2024): 123746.

[64] L. Wenkai, X. Zhiyong, and Z. Haodong, “Current Status of Research on Composite Bipolar Plates for Proton Exchange Membrane Fuel Cells (PEMFCs): Nanofillers and Structure Optimization,” RSC Advances 14, no. 10 (2024): 7172–7194.

[65] J. H. Yeon, S. J. Park, I. Choi, and M. Choi, “Generation of Carbon Nano-Onions by Laser Irradiation of Gaseous Hydrocarbons for High Durability Catalyst Support in Proton Exchange Membrane Fuel Cells,” Journal of Industrial and Engineering Chemistry 80 (2019): 65–73.

[66] R. T. James and F. Amaku, “Nanocomposites of Carbon for Fuel Cells.” in Engineering Materials, ed. R. K. Gupta (Springer Nature Singapore, 2024).

[67] K. Calamba, C. Ringor, C. Pascua, and K. Miyazawa, “Pleated Surface Morphology of C₆₀ Fullerene Nanowhiskers Incorporated by Polyaniline in N-Methyl-2-Pyrrolidone,” Fullerenes, Nanotubes and Carbon Nanostructures 23, no. 8 (2015): 709–714.

[68] Z. Ding, M. Cai, and X. Hui, “Potential of Vanadium (V) Doped CNT(10, 0) and Manganese (Mn) Doped Carbon Nanocage (C₆₀) as Catalysts for Oxygen Reduction Reaction in Fuel Cells,” Inorganic Chemistry Communications 135 (2022): 109095.

[69] C. J. T. de Grotthuss, “Sur la décomposition de l'eau et des corps qu'elle tient en dissolution à l'aide de l’électricité galvanique,” Annales de Chimie France 58 (1806): 54–73.

[70] K.-D. Kreuer, S. J. Paddison, E. Spohr, and M. Schuster, “Transport in Proton Conductors for Fuel-Cell Applications: Simulations, Elementary Reactions, and Phenomenology,” Chemical Reviews 104, no. 10 (2004): 4637–4678.

[71] K.-D. Kreuer, “Proton Conductivity: Materials and Applications,” Chemistry of Materials 8, no. 3 (1996): 610–641.

[72] T. Norby, “Solid-State Protonic Conductors: Principles, Properties, Progress and Prospects,” Solid State Ionics 125, no. 1–4 (1999): 1–11.

[73] K. Tasaki, “Carbonaceous Materials as Proton Conductors,” Journal of the Electrochemical Society 153, no. 5 (2006): A941.

[74] M. Šala, M. Hodošček, S. Arulmozhiraja, and T. Fujii, “Complete Set of Critical Points on the C₆₀H⁺ Potential Energy Surface,” Journal of Physical Chemistry A 113, no. 13 (2009): 3223–3226.

[75] A. P. Saab, G. D. Stucky, S. Passerini, and W. H. Smyrl, “Ionic Conductivity of C₆₀-Based Solid Electrolyte,” Fullerene Science and Technology 6, no. 2 (1998): 227–242.

[76] K. Tasaki, J. Gasa, H. Wang, and R. DeSousa, “Fabrication and Characterization of Fullerene–Nafion Composite Membranes,” Polymer 48, no. 15 (2007): 4438–4448.

[77] S. J. Peighambardoust, S. Rowshanzamir, and M. Amjadi, “Review of the Proton Exchange Membranes for Fuel Cell Applications,” International Journal of Hydrogen Energy 35, no. 17 (2010): 9349–9384.

[78] K. Jiao, J. Xuan, Q. Du, et al., “Designing the Next Generation of Proton-Exchange Membrane Fuel Cells,” Nature 595, no. 7867 (2021): 361–369.

[79] M. M. Tellez-Cruz, J. Escorihuela, O. Solorza-Feria, and V. Compañ, “Proton Exchange Membrane Fuel Cells (PEMFCs): Advances and Challenges,” Polymers 13, no. 18 (2021): 3064.

[80] E. Qu, X. Hao, M. Xiao, et al., “Proton Exchange Membranes for High Temperature Proton Exchange Membrane Fuel Cells: Challenges and Perspectives,” Journal of Power Sources 533 (2022): 231386.

[81] R. Haider, Y. Wen, Z.-F. Ma, et al., “High Temperature Proton Exchange Membrane Fuel Cells: Progress in Advanced Materials and Key Technologies,” Chemical Society Reviews 50, no. 2 (2021): 1138–1187.

[82] M. Vinothkannan, A. R. Kim, and D. J. Yoo, “Potential Carbon Nanomaterials as Additives for State-of-The-Art Nafion Electrolyte in Proton-Exchange Membrane Fuel Cells: A Concise Review,” RSC Advances 11, no. 30 (2021): 18351–18370.

[83] J. Coro, M. Suárez, L. S. R. Silva, K. I. B. Eguiluz, and G. R. Salazar-Banda, “Fullerene Applications in Fuel Cells: A Review,” International Journal of Hydrogen Energy 41, no. 40 (2016): 17944–17959.

[84] A. L. Dicks, “The Role of Carbon in Fuel Cells,” Journal of Power Sources 156, no. 2 (2006): 128–141.

[85] P. Schiebel, K. Wulf, W. Prandl, G. Heger, R. Papoular, and W. Paulus, “Orientationa Disorder, the Orientational Density Distribution and the Rotational Potential in C₆₀,” Acta Crystallographica. Section A: Foundations of Crystallography 52, no. 2 (1996): 176–188.

[86] J. Gasa, H. Wang, R. DeSousa, and K. Tasaki, “Fundamental Characterization of Fullerenes and Their Applications for Proton-Conducting Materials in PEMFC,” ECS Transactions 11, no. 1 (2007): 131–141.

[87] C. A. Reed, K.-C. Kim, R. D. Bolskar, and L. J. Mueller, “Taming Superacids: Stabilization of the Fullerene Cations HC₆₀⁺ and C₆₀⁺,” Science 289, no. 5476 (2000): 101–104.

[88] Y. Wang and F. Liu, “Fullerene Rotation Dictated by Benzene–Fullerene Interactions,” Inorganic Chemistry Frontiers 11, no. 12 (2024): 3458–3464.

[89] M. M. Olmstead, D. A. Costa, K. Maitra, et al., “Interaction of Curved and Flat Molecular Surfaces the Structures of Crystalline Compounds Composed of Fullerene (C₆₀, C₆₀O, C₇₀, and C₁₂₀O) and Metal Octaethylporphyrin Units,” Journal of the American Chemical Society 121, no. 30 (1999): 7090–7097.

[90] Y. Hao, Y. Wang, L. Spree, and F. Liu, “Rotation of Fullerene Molecules in the Crystal Lattice of Fullerene/Porphyrin: C₆₀ and Sc₃N@C₈₀,” Inorganic Chemistry Frontiers 8, no. 1 (2021): 122–126.

[91] Y. Hao, Y. Wang, C. G. Feiler, M. S. Weiss, A. A. Popov, and F. Liu, “The Hidden Features of Fullerene Rotation in the Crystal Lattice,” Inorganic Chemistry Frontiers 11, no. 19 (2024): 6343–6349.

[92] S. C. Pal, D. Mukherjee, R. Sahoo, S. Mondal, and M. C. Das, “Proton-Conducting Hydrogen-Bonded Organic Frameworks,” ACS Energy Letters 6, no. 12 (2021): 4431–4453.

[93] K. A. Mauritz and R. B. Moore, “State of Understanding of Nafion,” Chemical Reviews 104, no. 10 (2004): 4535–4586.

[94] K. N. S. D. V. Postnov, N. A. Melnikova, and V. N. Postnov, “Nafion-Based Nanocomposites With Light Fullerenes and Their Functionalized Derivatives,” Reviews on Advanced Materials Science 39, no. 1 (2014): 20–24.

[95] D. V. Postnov, V. N. Postnov, I. V. Murin, N. A. Mel'nikova, and K. N. Semenov, “Nafion-Based Composite Solid Electrolytes Containing Water-Soluble Fullerene C₆₀ Derivatives,” Russian Journal of General Chemistry 86, no. 4 (2016): 894–896.

[96] S. Saga, H. Matsumoto, K. Saito, M. Minagawa, and A. Tanioka, “Polyelectrolyte Membranes Based on Hydrocarbon Polymer Containing Fullerene,” Journal of Power Sources 176, no. 1 (2008): 16–22.

[97] K. Tasaki, R. Desousa, H. Wang, et al., “Fullerene Composite Proton Conducting Membranes for Polymer Electrolyte Fuel Cells Operating Under Low Humidity Conditions,” Journal of Membrane Science 281, no. 1–2 (2006): 570–580.

[98] K. Tasaki, “Fullerene Additives for Proton Exchange Membranes in Dry and High Temperature Operation of PEFC,” ECS Proceedings Volumes 2004–21, no. 1 (2004): 259–266.

[99] Z. Chen and W. Thiel, “Performance of Semiempirical Methods in Fullerene Chemistry: Relative Energies and Nucleus-Independent Chemical Shifts,” Chemical Physics Letters 367, no. 1–2 (2003): 15–25.

[100] G. V. Andrievsky, V. K. Klochkov, A. B. Bordyuh, and G. I. Dovbeshko, “Comparative Analysis of Two Aqueous-Colloidal Solutions of C₆₀ Fullerene With Help of FTIR Reflectance and UV–Vis Spectroscopy,” Chemical Physics Letters 364, no. 1–2 (2002): 8–17.

[101] L. Fomina, A. Reyes, P. Guadarrama, and S. Fomine, “Oniom (MP2:PM3) Study of C₆₀ –Water Complex,” International Journal of Quantum Chemistry 97, no. 1 (2004): 679–687.

[102] Y. Hashikawa, S. Sadai, Y. Ikemoto, and Y. Murata, “Open-[60]Fullerenols With Water Adsorbed Both Inside and Outside,” Chemical Communications 60, no. 10 (2024): 1261–1264.

[103] J. L. Atwood, F. Hamada, K. D. Robinson, G. W. Orr, and R. L. Vincent, “X-Ray Diffraction Evidence for Aromatic π Hydrogen Bonding to Water,” Nature 349, no. 6311 (1991): 683–684.

[104] S. Sweetnam, K. Vandewal, E. Cho, et al., “Characterizing the Polymer:Fullerene Intermolecular Interactions,” Chemistry of Materials 28, no. 5 (2016): 1446–1452.

[105] A. Guerrero, L. F. Marchesi, P. P. Boix, et al., “How the Charge-Neutrality Level of Interface States Controls Energy Level Alignment in Cathode Contacts of Organic Bulk-Heterojunction Solar Cells,” ACS Nano 6, no. 4 (2012): 3453–3460.

[106] R. I. Gearba, T. Mills, J. Morris, R. Pindak, C. T. Black, and X. Zhu, “Quantifying Interfacial Electric Fields and Local Crystallinity in Polymer–Fullerene Bulk-Heterojunction Solar Cells,” Advanced Functional Materials 21, no. 14 (2011): 2666–2673.

[107] J. Gao, A. K. Thomas, R. Johnson, H. Guo, and J. K. Grey, “Spatially Resolving Ordered and Disordered Conformers and Photocurrent Generation in Intercalated Conjugated Polymer/Fullerene Blend Solar Cells,” Chemistry of Materials 26, no. 15 (2014): 4395–4404.

[108] A. V. Penkova, M. E. Dmitrenko, M. P. Sokolova, et al., “Impact of Fullerene Loading on the Structure and Transport Properties of Polysulfone Mixed-Matrix Membranes,” Journal of Materials Science 51, no. 16 (2016): 7652–7659.

[109] B. D. Naab, S. Guo, S. Olthof, et al., “Mechanistic Study on the Solution-Phase N-Doping of 1,3-Dimethyl-2-Aryl-2,3-Dihydro-1H-Benzoimidazole Derivatives,” Journal of the American Chemical Society 135, no. 40 (2013): 15018–15025.

[110] T. V. Tropin, M. V. Avdeev, N. Jargalan, M. O. Kuzmenko, and V. L. Aksenov, “Kinetics of Cluster Growth in Fullerene Solutions of Different Polarity,” in Modern Problems of the Physics of Liquid Systems. Springer, 2019), 249–272.

[111] T. V. Tropin, N. Jargalan, M. V. Avdeev, and V. L. Aksenov, “Investigations of the Kinetics of Cluster Growth in Fullerene C₆₀ Solutions,” Ukrainian Journal of Physics 65, no. 8 (2020): 701.

[112] G. V. Andrievsky, V. K. Klochkov, E. L. Karyakina, and N. O. Mchedlov-Petrossyan, “Studies of Aqueous Colloidal Solutions of Fullerene C₆₀ by Electron Microscopy,” Chemical Physics Letters 300, no. 3–4 (1999): 392–396.

[113] M. V. Avdeev, V. L. Aksenov, and T. V. Tropin, “Models of Cluster Formation in Solutions of Fullerenes,” Russian Journal of Physical Chemistry A 84, no. 8 (2010): 1273–1283.

[114] S. Nath, H. Pal, and A. V. Sapre, “Effect of Solvent Polarity on the Aggregation of C₆₀,” Chemical Physics Letters 327, no. 3–4 (2000): 143–148.

[115] R. G. Alargova, S. Deguchi, and K. Tsujii, “Stable Colloidal Dispersions of Fullerenes in Polar Organic Solvents,” Journal of the American Chemical Society 123, no. 43 (2001): 10460–10467.

[116] C. M. Hansen and A. L. Smith, “Using Hansen Solubility Parameters to Correlate Solubility of C₆₀ Fullerene in Organic Solvents and In Polymers,” Carbon 42, no. 8–9 (2004): 1591–1597.

[117] A. Anis, M. Alam, A. Alhamidi, R. K. Gupta, M. Tariq, and S. M. Al-Zahrani, “Studies on Polybenzimidazole and Methanesulfonate Protic-Ionic-Liquids-Based Composite Polymer Electrolyte Membranes,” Polymers 15, no. 13 (2023): 2821.

[118] H. Luo, F. Yang, C. Li, et al., “Polybenzimidazole-Based Polymers of Intrinsic Microporosity Membrane for High-Temperature Proton Conduction,” Chemical Engineering Journal 476 (2023): 146611.

[119] J. Song, W. Zhao, L. Zhou, et al., “Rational Materials and Structure Design for Improving the Performance and Durability of High Temperature Proton Exchange Membranes (HT-PEMs),” Advanced Science 10, no. 30 (2023): 2303969.

[120] M. Yamada and A. Goto, “Proton Conduction of DNA–Imidazole Composite Material Under Anhydrous Condition,” Polymer Journal 44, no. 5 (2012): 415–420.

[121] F. Diederich and C. Thilgen, “Covalent Fullerene Chemistry,” Science 271, no. 5247 (1996): 317–324.

[122] F. Diederich and M. Gómez-López, “Supramolecular Fullerene Chemistry,” Chemical Society Reviews 28, no. 5 (1999): 263–277.

[123] K. Balasubramanian and M. Burghard, “Chemie des Graphens,” Chemie in Unserer Zeit 45, no. 4 (2011): 240–249.

[124] P.-C. Ma, N. A. Siddiqui, G. Marom, and J.-K. Kim, “Dispersion and Functionalization of Carbon Nanotubes for Polymer-Based Nanocomposites: A Review,” Composites, Part A: Applied Science and Manufacturing 41, no. 10 (2010): 1345–1367.

[125] S. Banerjee, M. G. C. Kahn, and S. S. Wong, “Rational Chemical Strategies for Carbon Nanotube Functionalization,” Chemistry—A European Journal 9, no. 9 (2003): 1898–1908.

[126] J. Li, A. Takeuchi, M. Ozawa, X. Li, K. Saigo, and K. Kitazawa, “C₆₀ Fullerol Formation Catalysed by Quaternary Ammonium Hydroxides,” Journal of the Chemical Society, Chemical Communications no. 23 (1993): 1784, https://doi.org/10.1039/c39930001784.

[127] L. Y. Chiang, L.-Y. Wang, J. W. Swirczewski, S. Soled, and S. Cameron, “Efficient Synthesis of Polyhydroxylated Fullerene Derivatives via Hydrolysis of Polycyclosulfated Precursors,” Journal of Organic Chemistry 59, no. 14 (1994): 3960–3968.

[128] A. A. Yurkova, E. A. Khakina, S. I. Troyanov, et al., “Arbuzov Chemistry With Chlorofullerene C₆₀Cl₆: A Powerful Method for Selective Synthesis of Highly Functionalized [60]Fullerene Derivatives,” Chemical Communications 48, no. 71 (2012): 8916.

[129] K. Hinokuma and M. Ata, “Fullerene Proton Conductors,” Chemical Physics Letters 341, no. 5–6 (2001): 442–446.

[130] T. A. Zawodzinski, C. Derouin, S. Radzinski, et al., “Water Uptake by and Transport Through Nafion® 117 Membranes,” Journal of the Electrochemical Society 140, no. 4 (1993): 1041–1047.

[131] A. I. Baranov, V. V. Sinitsyn, V. Y. Vinnichenko, D. J. Jones, and B. Bonnet, “Stabilisation of Disordered Superprotonic Phases in Crystals of the M₅H₃(AO₄)₄·xH₂O Family,” Solid State Ionics 97, no. 1–4 (1997): 153–160.

[132] Y. Li, “Proton Conductivity of Tungsten Trioxide Hydrates at Intermediate Temperature,” Solid State Ionics 134, no. 3–4 (2000): 271–279.

[133] H. Iwahara, “Proton Conducting Ceramics and Their Applications,” Solid State Ionics 86–88 (1996): 9–15.

[134] M. Sakaino, Y. Sun, and F. Morimoto, “Electrical Properties of Fullerenol C₆₀(OH)₁₀/Au Interface,” Journal of Applied Physics 115, no. 2 (2014): 23701.

[135] N. N. Rabin, M. R. Karim, M. S. Islam, et al., “Oxidation Route Dependent Proton Conductivities of Oxidized Fullerenes,” New Journal of Chemistry 41, no. 23 (2017): 14708–14712.

[136] E. E. Fileti, R. Rivelino, F. Brito Mota, and T. Malaspina, “Effects of Hydroxyl Group Distribution on the Reactivity, Stability and Optical Properties of Fullerenols,” Nanotechnology 19, no. 36 (2008): 365703.

[137] K. N. Semenov, D. G. Letenko, N. A. Charykov, et al., “Synthesis and Identification of Fullerenol Prepared by the Direct Oxidation Route,” Russian Journal of Applied Chemistry 83, no. 12 (2010): 2076–2080.

[138] J. M. Zhang, W. Yang, P. He, and S. Z. Zhu, “Efficient and Convenient Preparation of Water-Soluble Fullerenol,” Chinese Journal of Chemistry 22, no. 9 (2004): 1008–1011.

[139] S. Keshri and B. L. Tembe, “Thermodynamics of Hydration of Fullerols [C60(OH)n] and Hydrogen Bond Dynamics in Their Hydration Shells,” Journal of Chemical Physics 146, no. 7 (2017): 74501.

[140] Y. Tajima and K. Takeuchi, “Discovery of C60O3 Isomer Having C3ν Symmetry,” Journal of Organic Chemistry 67, no. 5 (2002): 1696–1698.

[141] J. P. Guthrie, “Hydrolysis of Esters of Oxy Acids: PK_A Values for Strong Acids; Brønsted Relationship for Attack of Water at Methyl; Free Energies of Hydrolysis of Esters of Oxy Acids; and a Linear Relationship Between Free Energy of Hydrolysis and pK_a Holding Over a Range of 20 pK Units,” Canadian Journal of Chemistry 56, no. 17 (1978): 2342–2354.

[142] V. V. Ignatev, S. G. Muller, S. G. Pasynkov, A. M. Petunin, and K. A. Bardina, “Classification of Methods for the Synthesis of Polyhydroxylated Fullerenes Part 1 One‑Step Reactions,” Chemistry and Technology of Fuels and Oils 60, no. 1 (2024): 52–58.

[143] V. V. Ignatev, R. Muller, S. G. Pasynkov, A. M. Petunin, and K. A. Bardina, “Classification of the Methods for the Synthesis of Polyhydroxylated Fullerenes Part 2 One‑Step and Multi‑Step Procedures,” Chemistry and Technology of Fuels and Oils 60, no. 2 (2024): 263–266.

[144] K. Kokubo, S. Shirakawa, N. Kobayashi, H. Aoshima, and T. Oshima, “Facile and Scalable Synthesis of a Highly Hydroxylated Water-Soluble Fullerenol as a Single Nanoparticle,” Nano Research 4, no. 2 (2011): 204–215.

[145] S. Afreen, K. Kokubo, K. Muthoosamy, and S. Manickam, “Hydration or Hydroxylation: Direct Synthesis of Fullerenol From Pristine Fullerene [C₆₀] via Acoustic Cavitation in the Presence of Hydrogen Peroxide,” RSC Advances 7, no. 51 (2017): 31930–31939.

[146] B. Mecheri, A. D'Epifanio, M. L. Di Vona, E. Traversa, S. Licoccia, and M. Miyayama, “Sulfonated Polyether Ether Ketone-Based Composite Membranes Doped With a Tungsten-Based Inorganic Proton Conductor for Fuel Cell Applications,” Journal of the Electrochemical Society 153, no. 3 (2006): A463.

[147] K. Hinokuma and M. Ata, “Proton Conduction in Polyhydroxy Hydrogensulfated Fullerenes,” Journal of the Electrochemical Society 150, no. 1 (2003): A112.

[148] E. T. Hoke, I. T. Sachs-Quintana, M. T. Lloyd, et al., “The Role of Electron Affinity in Determining Whether Fullerenes Catalyze or Inhibit Photooxidation of Polymers for Solar Cells,” Advanced Energy Materials 2, no. 11 (2012): 1351–1357.

[149] L. N. Inasaridze, A. I. Shames, I. V. Martynov, et al., “Light-Induced Generation of Free Radicals by Fullerene Derivatives: An Important Degradation Pathway in Organic Photovoltaics?,” Journal of Materials Chemistry A 5, no. 17 (2017): 8044–8050.

[150] A. Levitsky, S. A. Schneider, E. Rabkin, M. F. Toney, and G. L. Frey, “Bridging the Thermodynamics and Kinetics of Temperature-Induced Morphology Evolution in Polymer/Fullerene Organic Solar Cell Bulk Heterojunction,” Materials Horizons 8, no. 4 (2021): 1272–1285.

[151] S. Aghili, M. Panjepour, and M. Ghiaci, “Degradation Mechanism and Oxidation Kinetics of C₆₀ Fullerene,” Diamond and Related Materials 124 (2022): 108943.

[152] G. Lisa, C. I. Cleminte, and T. Michinobu, “Thermal Stability and Degradation Mechanism of C₆₀ Fullerene-Based Polymers,” Journal of Applied Polymer Science 141, no. 11 (2024): e55079.

[153] R. Maruyama, M. Shiraishi, K. Hinokuma, A. Yamada, and M. Ata, “Electrolysis of Water Vapor Using a Fullerene-Based Electrolyte,” Electrochemical and Solid-State Letters 5, no. 4 (2002): A74.

[154] L. Dai, J. Lu, B. Matthews, and A. W. H. Mau, “Doping of Conducting Polymers by Sulfonated Fullerene Derivatives and Dendrimers,” Journal of Physical Chemistry B 102, no. 21 (1998): 4049–4053.

[155] R. S. Kohlman, D. B. Tanner, G. G. Ihas, Y. G. Min, A. G. MacDiarmid, and A. J. Epstein, “Inhomogeneous Insulator-Metal Transition in Conducting Polymers,” Synthetic Metals 84, no. 1–3 (1997): 709–714.

[156] Y. Kanbur and Z. Küçükyavuz, “Synthesis and Characterization of Surface Modified Fullerene,” Fullerenes, Nanotubes and Carbon Nanostructures 20, no. 2 (2012): 119–126.

[157] B. G. Choi, Y. S. Huh, Y. C. Park, D. H. Jung, W. H. Hong, and H. Park, “Enhanced Transport Properties in Polymer Electrolyte Composite Membranes With Graphene Oxide Sheets,” Carbon 50, no. 15 (2012): 5395–5402.

[158] K. Feng, B. Tang, and P. Wu, “Sulfonated Graphene Oxide–Silica for Highly Selective Nafion-Based Proton Exchange Membranes,” Journal of Materials Chemistry A: Materials for Energy and Sustainability 2, no. 38 (2014): 16083–16092.

[159] J. Ji, G. Zhang, H. Chen, et al., “Sulfonated Graphene as Water-Tolerant Solid Acid Catalyst,” Chemical Science 2, no. 3 (2011): 484–487.

[160] Y. Sedesheva, V. Ivanov, A. Wozniak, and A. Yegorov, “Proton-Exchange Membranes Based on Sulfonated Polymers,” Oriental Journal of Chemistry 32, no. 5 (2016): 2283–2296.

[161] G. Rambabu and S. D. Bhat, “Sulfonated Fullerene in SPEEK Matrix and Its Impact on the Membrane Electrolyte Properties in Direct Methanol Fuel Cells,” Electrochimica Acta 176 (2015): 657–669.

[162] G. Rambabu, N. Nagaraju, and S. D. Bhat, “Functionalized Fullerene Embedded in Nafion Matrix: A Modified Composite Membrane Electrolyte for Direct Methanol Fuel Cells,” Chemical Engineering Journal 306 (2016): 43–52.

[163] B. M. Ginzburg, S. Tuichiev, S. K. Tabarov, A. A. Shepelevskii, and L. A. Shibaev, “X-Ray Diffraction Analysis of C₆₀ Fullerene Powder and Fullerene Soot,” Technical Physics 50, no. 11 (2005): 1458–1461.

[164] W. Zhu, D. E. Miser, W. Geoffrey Chan, and M. R. Hajaligol, “Characterization of Combustion Fullerene Soot, C₆₀, and Mixed Fullerene,” Carbon 42, no. 8–9 (2004): 1463–1471.

[165] J. H. Bae, A. M. Shanmugharaj, W. H. Noh, W. S. Choi, and S. H. Ryu, “Surface Chemical Functionalized Single-Walled Carbon Nanotube With Anchored Phenol Structures: Physical and Chemical Characterization,” Applied Surface Science 253, no. 9 (2007): 4150–4155.

[166] Z. Jiang, X. Zhao, Y. Fu, and A. Manthiram, “Composite Membranes Based on Sulfonated Poly(Ether Ether Ketone) and SDBS-Adsorbed Graphene Oxide for Direct Methanol Fuel Cells,” Journal of Materials Chemistry 22, no. 47 (2012): 24862.

[167] Y. Heo, H. Im, and J. Kim, “The Effect of Sulfonated Graphene Oxide on Sulfonated Poly (Ether Ether Ketone) Membrane for Direct Methanol Fuel Cells,” Journal of Membrane Science 425–426 (2013): 11–22.

[168] Z. Jiang, X. Zhao, and A. Manthiram, “Sulfonated Poly(Ether Ether Ketone) Membranes With Sulfonated Graphene Oxide Fillers for Direct Methanol Fuel Cells,” International Journal of Hydrogen Energy 38, no. 14 (2013): 5875–5884.

[169] G. Rambabu and S. D. Bhat, “Simultaneous Tuning of Methanol Crossover and Ionic Conductivity of sPEEK Membrane Electrolyte by Incorporation of PSSA Functionalized MWCNTs: A Comparative Study in DMFCs,” Chemical Engineering Journal 243 (2014): 517–525.

[170] S. Gahlot and V. Kulshrestha, “Dramatic Improvement in Water Retention and Proton Conductivity in Electrically Aligned Functionalized CNT/SPEEK Nanohybrid PEM,” ACS Applied Materials & Interfaces 7, no. 1 (2015): 264–272.

[171] M. Vinothkannan, A. R. Kim, G. Gnana kumar, and D. J. Yoo, “Sulfonated Graphene Oxide/Nafion Composite Membranes for High Temperature and Low Humidity Proton Exchange Membrane Fuel Cells,” RSC Advances 8, no. 14 (2018): 7494–7508.

[172] H.-C. Chien, L.-D. Tsai, C.-P. Huang, Cy Kang, J. N. Lin, and F. C. Chang, “Sulfonated Graphene Oxide/Nafion Composite Membranes for High-Performance Direct Methanol Fuel Cells,” International Journal of Hydrogen Energy 38, no. 31 (2013): 13792–13801.

[173] S. Neelakandan, D. Liu, L. Wang, M. Hu, and L. Wang, “Highly Branched Poly(Arylene Ether)/Surface Functionalized Fullerene-Based Composite Membrane Electrolyte for DMFC Applications,” International Journal of Energy Research 43, no. 8 (2019): 3756–3767.

[174] T. Hirakimoto, K. Fukushima, Y. Li, S. Takizawa, K. Hinokuma, and T. Senoo, “Fullerene-Based Proton-Conductive Material for the Electrolyte Membrane and Electrode of a Direct Methanol Fuel Cell,” ECS Transactions 16, no. 2 (2008): 2067–2072.

[175] U. Chakraborty, “Fuel Crossover and Internal Current in Proton Exchange Membrane Fuel Cell Modeling,” Applied Energy 163 (2016): 60–62.

[176] J. Walkowiak-Kulikowska, J. Wolska, and H. Koroniak, “Polymers Application in Proton Exchange Membranes for Fuel Cells (PEMFCs).” Polymer Engineering (Walter de Gruyter GmbH, 2017).

[177] M. Keshavarz-K, B. Knight, G. Srdanov, and F. Wudl, “Cyanodihydrofullerenes and Dicyanodihydrofullerene: The First Polar Solid Based on C₆₀,” Journal of the American Chemical Society 117, no. 45 (1995): 11371–11372.

[178] B. Jousselme, G. Sonmez, and F. Wudl, “Acidity and Electronegativity Enhancement of C₆₀ Derivatives Through Cyano Groups,” Journal of Materials Chemistry 16, no. 34 (2006): 3478.

[179] H. Wang, A. Venkatesan, K. Tasaki, et al., “Fullerene Composite Membranes for Low Humidity Operation of Polymer Electrolyte Fuel Cells: Part III,” ECS Transactions 1, no. 6 (2006): 183–188.

[180] H. Wang, R. DeSousa, J. Gasa, et al., “Fabrication of New Fullerene Composite Membranes and Their Application in Proton Exchange Membrane Fuel Cells,” Journal of Membrane Science 289, no. 1–2 (2007): 277–283.

[181] K. Tasaki, A. Venkatesan, H. Wang, B. Jousselme, G. Stucky, and F. Wudl, “Hydrogen Cyano Fullerene Derivatives as Acid for Proton Conducting Membranes,” Journal of the Electrochemical Society 155, no. 10 (2008): B1077.

[182] K. Miyatake, K. Fukushima, S. Takeoka, and E. Tsuchida, “Nonaqueous Proton Conduction in Poly(Thiophenylenesulfonic Acid)/Poly(Oxyethylene) Composite,” Chemistry of Materials 11, no. 5 (1999): 1171–1173.

[183] J. Ennari, I. Neelov, and F. Sundholm, “Simulation of a PEO Based Solid Polyelectrolyte, Comparison of the CMM and the Ewald Summation Method,” Polymer 41, no. 6 (2000): 2149–2155.

[184] M. F. H. Schuster, W. H. Meyer, M. Schuster, and K. D. Kreuer, “Toward a New Type of Anhydrous Organic Proton Conductor Based on Immobilized Imidazole,” Chemistry of Materials 16, no. 2 (2004): 329–337.

[185] H. Steininger, M. Schuster, K. D. Kreuer, et al., “Intermediate Temperature Proton Conductors for PEM Fuel Cells Based on Phosphonic Acid as Protogenic Group: A Progress Report,” Physical Chemistry Chemical Physics 9, no. 15 (2007): 1764–1773.

[186] H. Steininger, M. Schuster, K. Kreuer, and J. Maier, “Intermediate Temperature Proton Conductors Based on Phosphonic Acid Functionalized Oligosiloxanes,” Solid State Ionics 177, no. 26–32 (2006): 2457–2462.

[187] B. Lafitte and P. Jannasch, “Phosphonation of Polysulfones via Lithiation and Reaction With Chlorophosphonic Acid Esters,” Journal of Polymer Science, Part A: Polymer Chemistry 43, no. 2 (2005): 273–286.

[188] C. Hartmann-Thompson, A. Merrington, P. I. Carver, et al., “Proton-Conducting Polyhedral Oligosilsesquioxane Nanoadditives for Sulfonated Polyphenylsulfone Hydrogen Fuel Cell Proton Exchange Membranes,” Journal of Applied Polymer Science 110, no. 2 (2008): 958–974.

[189] V. A. Kuimov, E. A. Matveeva, S. F. Malysheva, et al., “Microwave-Assisted Catalyst-Free Addition of Secondary Phosphines to Fullerene C₆₀,” Mendeleev Communications 27, no. 2 (2017): 198–200.

[190] Y. Li, “Proton Conductivity of Phosphoric Acid Derivative of Fullerene,” Solid State Ionics 150, no. 3–4 (2002): 309–315.

[191] F. Cheng, X. Yang, H. Zhu, and Y. Song, “Synthesis and Optical Properties of Tetraethyl Methano[60]Fullerenediphosphonate,” Tetrahedron Letters 41, no. 20 (2000): 3947–3950.

[192] G. Alberti and M. Casciola, “Phosphates and Phosphonates of Tetravalent Metals as Protonic Conductors.” Proton Conductors (Cambridge University Press, 1992).

[193] Y. M. Li, K. Noda, and K. Hinokuma, “Nano-Composite of Phosphoric Acid Derivative of Fullerene With SiO₂ and Its Proton Conductivity,” Electrochemistry 75, no. 2 (2007): 243–247.

[194] M. Amjadi, S. Rowshanzamir, S. J. Peighambardoust, M. G. Hosseini, and M. H. Eikani, “Investigation of Physical Properties and Cell Performance of Nafion/TiO₂ Nanocomposite Membranes for High Temperature PEM Fuel Cells,” International Journal of Hydrogen Energy 35, no. 17 (2010): 9252–9260.

[195] M. Amjadi, S. Rowshanzamir, S. J. Peighambardoust, and S. Sedghi, “Preparation, Characterization and Cell Performance of Durable Nafion/SiO₂ Hybrid Membrane for High-Temperature Polymeric Fuel Cells,” Journal of Power Sources 210 (2012): 350–357.

[196] S. S. Rikame, A. A. Mungray, and A. K. Mungray, “Synthesis, Characterization and Application of Phosphorylated Fullerene/Sulfonated Polyvinyl Alcohol (PFSP) Composite Cation Exchange Membrane for Copper Removal,” Separation and Purification Technology 177 (2017): 29–39.

[197] A. Hirsch, I. Lamparth, T. Groesser, and H. R. Karfunkel, “Regiochemistry of Multiple Additions to the Fullerene Core: Synthesis of a Th-Symmetric Hexakis Adduct of C₆₀ With Bis(Ethoxycarbonyl)Methylene,” Journal of the American Chemical Society 116, no. 20 (1994): 9385–9386.

[198] I. Lamparth and A. Hirsch, “Water-Soluble Malonic Acid Derivatives of C₆₀ With a Defined Three-Dimensional Structure,” Journal of the Chemical Society, Chemical Communications no. 14 (1994): 1727, https://doi.org/10.1039/c39940001727.

[199] I. V. Kuvychko, N. B. Shustova, S. M. Avdoshenko, A. A. Popov, S. H. Strauss, and O. V. Boltalina, “In Search of Fullerene-Based Superacids: Synthesis, X-Ray Structure, and DFT Study of C₆₀(C₂F₅)₅H,” Chemistry—A European Journal 17, no. 32 (2011): 8799–8802.

[200] E. Grądzka, M. Wysocka-Żołopa, and K. Winkler, “Fullerene-Based Conducting Polymers: n-Dopable Materials for Charge Storage Application,” Advanced Energy Materials 10, no. 40 (2020): 2001443.

[201] P. J. F. Harris, “Fullerene Polymers: A Brief Review,” C 6, no. 4 (2020): 71.

RIGHTS & PERMISSIONS

2025 The Author(s). Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.