Abstract
State-of-the-art automotive fuel cells that operate at about 80 °C require large radiators and air intakes to avoid overheating. High-temperature fuel cells that operate above 100 °C under anhydrous conditions provide an ideal solution for heat rejection in heavy-duty vehicle applications. Here we report protonated phosphonic acid electrodes that remarkably improve the performance of high-temperature polymer electrolyte membrane fuel cells. The protonated phosphonic acids comprise tetrafluorostyrene-phosphonic acid and perfluorosulfonic acid polymers, where a perfluorosulfonic acid proton is transferred to the phosphonic acid to enhance the anhydrous proton conduction of fuel cell electrodes. By using this material in fuel cell electrodes, we obtained a fuel cell exhibiting a rated power density of 780 mW cm–2 at 160 °C, with minimal degradation during 2,500 h of operation and 700 thermal cycles from 40 to 160 °C under load.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Recent Advances on PEM Fuel Cells: From Key Materials to Membrane Electrode Assembly
Electrochemical Energy Reviews Open Access 17 August 2023
-
Low Pt loading for high-performance fuel cell electrodes enabled by hydrogen-bonding microporous polymer binders
Nature Communications Open Access 08 December 2022
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout






Data availability
The data supporting the findings of this study are available within the paper, Extended Data and Supplementary Information. Source data are provided with this paper.
References
Cano, Z. P. et al. Batteries and fuel cells for emerging electric vehicle markets. Nat. Energy 3, 279–289 (2018).
Cullen, D. A. et al. New roads and challenges for fuel cells in heavy-duty transportation. Nat. Energy 6, 462–474 (2021).
Forrest, K., Kinnon, M. M., Tarroja, B. & Samuelsen, S. Estimating the technical feasibility of fuel cell and battery electric vehicles for the medium and heavy duty sectors in California. Appl. Energy 276, 115439 (2020).
Hong, B. K., Kim, S. H. & Kim, C. M. Powering the future through hydrogen and polymer electrolyte membrane fuel cells. Current commercialisation and key challenges with focus on work at Hyundai. Johnson Matthey Technol. Rev. 64, 236–251 (2020).
Gittleman, C. S., Jia, H., De Castro, E. S., Chisholm, C. & Kim, Y. S. Proton conductors for heavy-duty vehicle fuel cells. Joule 5, 1660–1677 (2021).
US Drive Partnership Fuel Cell Technical Team Roadmap (US Department of Energy, 2017); https://www.energy.gov/sites/default/files/2017/11/f46/FCTT_Roadmap_Nov_2017_FINAL.pdf
Dicks, A. L. & Rand, D. A. J. Proton-Exchange Membrane Fuel Cells in Fuel Cell Systems Explained 3rd edn, 69–133 (John Wiley, 2018).
Valdés-López, V. F., Mason, T., Shearing, P. R. & Brett, D. J. L. Carbon monoxide poisoning and mitigation strategies for polymer electrolyte membrane fuel cells—a review. Prog. Energy Combust. Sci. 79, 100942 (2020).
Chan T. Methanol Fuel Cells: Powering the Future (Methanol Institute, 2020); https://www.methanol.org/wp-content/uploads/2020/04/Methanol-Fuel-Cell-Powering-the-Future-webinar-presentation.pdf
Park, C. H. et al. Nanocrack-regulated self-humidifying membranes. Nature 532, 480–483 (2016).
Yang, J. S. et al. High molecular weight polybenzimidazole membranes for high temperature PEMFC. Fuel Cells 14, 7–15 (2014).
Pingitore, A. T., Huang, F., Qian, G. Q. & Benicewicz, B. C. Durable high polymer content m/p-polybenzimidazole membranes for extended lifetime electrochemical devices. ACS Appl. Energy Mater. 2, 1720–1726 (2019).
Søndergaard, T. et al. Long-term durability of PBI-based HT-PEM fuel cells: effect of operating parameters. J. Electrochem. Soc. 165, F3053–F3062 (2018).
Jakobsen, M. T. D., Jensen, J. O., Cleemann, L. N. & Li, Q. in High Temperature Polymer Electrolyte Membrane Fuel Cells: Approaches, Status, and Perspectives (eds Li, Q. et al.) 487–509 (Springer, 2016).
Lee, K. S., Spendelow, J. S., Choe, Y. K., Fujimoto, C. & Kim, Y. S. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs. Nat. Energy 1, 16120 (2016).
Lee, A. S., Choe, Y. K., Matanovic, I. & Kim, Y. S. The energetics of phosphoric acid interactions reveals a new acid loss mechanism. J. Mater. Chem. A 7, 9867–9876 (2019).
Atanasov, V. et al. Synergistically integrated phosphonated poly(pentafluorostyrene)s for fuel cells. Nat. Mater. 20, 370–377 (2021).
Kongkanand, A. & Mathias, M. F. The priority and challenge of high-power performance of low-platinum proton-exchange membrane fuel cells. J. Phys. Chem. Lett. 7, 1127–1137 (2016).
Kotz, R., Clouser, S., Sarangapani, S. & Yeager, E. Ionization of trifluoromethane sulfonic acid in phosphoric acid: Raman studies. J. Electrochem. Soc. 131, 1097–1100 (1984).
Parvole, J. & Jannasch, P. Polysulfones grafted with poly(vinylphosphonic acid) for highly proton conducting fuel cell membranes in the hydrated and nominally dry state. Macromolecules 41, 3893–3903 (2008).
Aili, D. et al. Phosphoric acid dynamics in high temperature polymer electrolyte membranes. J. Electrochem. Soc. 167, 134507 (2020).
Haouas, M., Taulelle, F., Prudhomme, N. & Cambon, O. NMR analysis of GaPO4 crystal growth in mixtures of phosphoric and sulfuric acids. J. Cryst. Growth 296, 197–206 (2006).
Melchior, J.-P., Majer, G. & Kreuer, K.-D. Why do proton conducting benzimidazole phosphoric acid membranes perform well in high-temperature PEM fuel cells? Phys. Chem. Chem. Phys. 19, 601–612 (2017).
Frisch, M. J., Head-Gordon, M. & Pople, J. A. Direct MP2 gradient method. Chem. Phys. Lett. 166, 275–280 (1990).
Zhang, S. M., Baker, J. & Pulay, P. A reliable and efficient first principles-based method for predicting pKa values. 1. Methodology. J. Phys. Chem. A 114, 425–431 (2010).
Matanovic, I., Chung, H. T. & Kim, Y. S. Benzene adsorption: a significant inhibitor for the hydrogen oxidation reaction in alkaline conditions. J. Phys. Chem. Lett. 8, 4918–4924 (2017).
Li, D., Chung, H. T., Maurya, S., Matanovic, I. & Kim, Y. S. Impact of ionomer adsorption on alkaline hydrogen oxidation activity and fuel cell performance. Curr. Opin. Electrochem. 12, 189–195 (2018).
He, Q. G., Shyam, B., Nishijima, M. & Ramaker, D. Mitigating phosphate anion poisoning of cathodic Pt/C catalysts in phosphoric acid fuel cells. J. Phys. Chem. C. 117, 4877–4887 (2013).
Li, Q. et al. Phosphate-tolerant oxygen reduction catalysts. ACS Catal. 4, 3193–3200 (2014).
Lee, K.-S. et al. Intermediate temperature fuel cells via an ion-pair coordinated polymer electrolyte. Energy Environ. Sci. 11, 979–987 (2018).
Eberhardt, S. H. et al. Dynamic operation of HT-PEFC: in-operando imaging of phosphoric acid profiles and (re)distribution. J. Electrochem. Soc. 162, F310–F316 (2015).
Matanovic, I., Lee, A. S. & Kim, Y. S. Energetics of base–acid pairs for the design of high-temperature fuel cell polymer electrolytes. J. Phys. Chem. B 124, 7725–7734 (2020).
Maurya, S. et al. Rational design of polyaromatic ionomers for alkaline membrane fuel cells with >1 W cm–2 power density. Energy Environ. Sci. 11, 3283–3291 (2018).
Ott, S. et al. Ionomer distribution control in porous carbon-supported catalyst layers for high-power and low Pt-loaded proton exchange membrane fuel cells. Nat. Energy 19, 77–85 (2020).
Cleve, T. V. et al. Tailoring electrode microstructure via ink content to enable improved rated power performance for platinum cobalt/high surface area carbon based polymer electrolyte fuel cells. J. Power Sources 482, 228889 (2021).
Lai, Y.-H. et al. Accelerated stress testing of fuel cell membranes subjected to combined mechanical/chemical stressors and cerium migration. J. Electrochem. Soc. 165, F3100–F3103 (2018).
Noh, S., Jeon, J. Y., Adhikari, S., Kim, Y. S. & Bae, C. Molecular engineering of hydroxide conducting polymers for anion exchange membranes in electrochemical energy conversion technology. Acc. Chem. Res. 52, 2745–2755 (2019).
Wang, J. et al. Poly(aryl piperidinium) membranes and ionomers for hydroxide exchange membrane fuel cells. Nat. Energy 4, 392–398 (2019).
Mader, J., Xiao, L., Schmidt, T. J. & Benicewicz, B. C. Polybenzimidazole/acid complexes as high-temperature membranes. Adv. Polym. Sci. 216, 63–124 (2008).
Li, X. et al. Highly conductive and mechanically stable imidazole-rich cross-linked networks for high-temperature proton exchange membrane fuel cells. Chem. Mater. 32, 1182–1191 (2020).
Krishnan, N. N. et al. Phosphoric acid doped crosslinked polybenzimidazole (PBI-OO) blend membranes for high temperature polymer electrolyte fuel cells. J. Membr. Sci. 544, 416–424 (2017).
Wang, L., Liu, Z., Liu, Y. & Wang, L. Crosslinked polybenzimidazole containing branching structure with no sacrifice of effective N-H sites: Towards high-performance high-temperature proton exchange membranes for fuel cells. J. Membr. Sci. 583, 110–117 (2019).
Ghosh, P. et al. Enhanced power generation, faster transient response and longer durability of HT-PEMFC using composite benzimidazole electrolyte membrane with optimum rGO loading. Int. J. Hydrogen Energy 45, 16708–16723 (2020).
Xie, J., Wood, D. L., More, K. L., Atanassov, P. & Borup, R. L. Microstructural changes of membrane electrode assemblies during PEFC durability testing at high humidity conditions. J. Electrochem. Soc. 152, A1011–A1020 (2005).
Yu, J. R., Matsuura, T., Yoshikawa, Y., Islam, M. N. & Hori, M. In situ analysis of performance degradation of a PEMFC under nonsaturated humidification. Electrochem. Solid State Lett. 8, A156–A158 (2005).
Schmidt, T. J. & Baurmeister, J. Properties of high-temperature PEFC Celtec®-P 1000 MEAs in start/stop operation mode. J. Power Sources 176, 428–434 (2008).
Borup, R. et al. Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chem. Rev. 107, 3904–3951 (2007).
Marcinkoski, J. et al. Hydrogen Class 8 Long Haul Truck Targets (US DOE, 2019); https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf
Hibbs, M. R. Alkaline stability of poly(phenylene)-based anion exchange membranes with various cations. J. Polym. Sci. B 51, 1736–1742 (2013).
Maurya, S., Fujimoto, C., Hibbs, M. R., Villarrubia, C. N. & Kim, Y. S. Toward improved alkaline membrane fuel cell performance using quaternized aryl-ether free polyaromatics. Chem. Mater. 30, 2188–2192 (2018).
Atanasov, V. & Kerres, J. Highly phosphonated polypentafluorostyrene. Macromolecules 44, 6416–6423 (2011).
Marenich, A. V., Cramer, C. J. & Truhlar, D. G. Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions. J. Phys. Chem. B 113, 6378–6396 (2009).
Zhao, Y. & Truhlar, D. G. The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals. Theor. Chem. Acc. 120, 215–241 (2008).
Frisch, M. J. et al. Gaussian 09 Revision C.01 (Gaussian, 2010).
Zhao, Y. & Truhlar, D. G. A new local density functional for main-group thermochemistry, transition metal bonding, thermochemical kinetics, and noncovalent interactions. J. Chem. Phys. 125, 194101 (2006).
Kim, Y. S. et al. Origin of toughness in dispersion-cast Nafion membranes. Macromolecules 48, 2161–2172 (2015).
Asghari, S., Mokmeli, A. & Samavati, M. Study of PEM fuel cell performance by electrochemical impedance spectroscopy. Int. J. Hydrogen Energy 35, 9283–9290 (2010).
Stampino, P. G. et al. Investigation of hydrophobic treatments with perfluoropolyether derivatives of gas diffusion layers by electrochemical impedance spectroscopy in PEM-FC. Solid State Ion. 216, 100–104 (2012).
Liang, H., Su, H., Pollet, B. G., Linkov, V. & Pasupathi, S. Membrane electrode assembly with enhanced platinum utilization for high temperature proton exchange membrane fuel cell prepared by catalyst coating membrane method. J. Power Sources 266, 107–113 (2014).
Acknowledgements
PA-PBI samples were provided by E. S. De Castro (Advent Technologies). We thank A. Muenchinger (MPI) and K. D. Kreuer (MPI) for the conductivity data on PWN. This work was supported by the US Department of Energy, Energy Efficiency and Renewable Energy, Fuel Cell Technology Office (L’Innovator program) and Advanced Research Projects Agency-Energy (award number DE-AR0001003). The synthesis of the PWN polymer was developed and supported by the following German National Projects: DFG KE 673/10-1 no. 576968, BMBF 03SF0432B and 03SF0531C. A.S.L. acknowledges support from the KIST internal research program and the National R&D Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2020M3H4A3106354 and 2020M3H4A3106403). Los Alamos National Laboratory is operated by Triad National Security under US Department of Energy Contract Number 89233218CNA000001. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, a wholly owned subsidiary of Honeywell International, for the US Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. I.M. acknowledges access to the computational resources of LANL Institutional Computing Program, which is supported by the US Department of Energy National Nuclear Security Administration under contract 89233218CNA000001, NERSC, a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under contract DE-AC02-05CH11231, and CARC, UNM Center for Advanced Research Computing.
Author information
Authors and Affiliations
Contributions
A.S.L. and Y.S.K. developed the intellectual concept and designed all the experiments of this research. V.A., J.K., S.A. and C.F. prepared the polymeric materials. E.J.P., S.M., L.D.M., J. Jung, Z.H. and H.J. synthesized the model compounds and performed the electrochemical experiments. J. Jankovic performed the TEM and image analyses. K.H.L., S.M. and A.S.L. tested the fuel cells. I.M. performed the DFT calculations. K.H.L., A.S.L. and Y.S.K. analysed all the experimental data and wrote the paper.
Corresponding author
Ethics declarations
Competing interests
A.S.L. and Y.S.K. filed a US patent application (application no. 17/196283) on 9 March 2021 related to the ionomer composition described in this article. Z.H. and H.J. are employed by Toyota Research Institute of North America. The remaining authors declare no competing interests.
Peer review
Peer review information
Nature Energy thanks Søren Andreasen, Jiujun Zhang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data
Extended Data Fig. 1 DFT calculations on protonation of PFPA.
(a) Linear regression fit to deprotonation energies using the difference in DFT calculated electronic energy (ΔE) of A−and HA. The ΔE values are calculated using SMD solvation model with water as solvent at the M062X/6-311 + +G(d,p) level. Equation of line is determined as \(pK_a = 0.108 \ast {\Delta}E - 28.2\) with R2 of 0.90 and rms error of 0.2 pKa units. (b) DFT structures that correspond to calculated 31P NMR shifts; M06L/6-311 + G(2d,p) level of theory and (c) Optimized structure of one perfluoroethanesulfonic acid in interaction with three PFPAs.
Extended Data Fig. 2 EIS characterization of MEA using the Nafion/PWN composite ionomer as a function of IEC of PWN at 0.6 V.
Composite ionomers: Nafion/PWN-0.9, Nafion/PWN-1.8 and Nafion/PWN-3.0 (Nafion content = 0.5). The impedance with frequency range from 1 MHz to 0.1 Hz was measured under H2/O2 conditions at 160 °C and 170 kPa backpressure.
Extended Data Fig. 3 Proton conductivity of Nafion, PWN, and Nafion/PWN mixture in DMSO (solid content: 5 wt%).
PWN-0, 0.9, 1.3, 1.8 and 3.0. The Nafion content of the ionomer = 0.5. Mean ± s.d. (n = 3) are shown. Compared to the conductivity in NMP, the conductivity of Nafion, PWN, and Nafion/PWN increased in DMSO.
Extended Data Fig. 4 H2/O2 fuel cell performance of MEAs employing Nafion/PWN-1.8 as a function of Nafion content.
MEA component: QAPOH-PA ion-pair membrane, anode (Pt-Ru/C, 0.5 mgPt cm-2), and cathode (Pt/C, 0.7 mgPt cm-2).
Extended Data Fig. 5 EIS characterization of MEA using the Nafion, (1:0), protonated phosphonic acid and non-protonated phosphonic acid ionomers.
(a) 0.8 V (b) 0.6 V and (c) 2 A cm-2. Ionomers: Nafion (Nafion content = 1), protonated phosphonic acid ionomer (Nafion content = 0.4), non-protonated phosphonic acid ionomer (Nafion content = 0). The impedance was measured with frequency range from 1 MHz to 0.1 Hz under H2/O2 condition at 160 °C and 170 kPa backpressure.
Extended Data Fig. 6 Impact of phosphoric acid and phenyl adsorption on ECSA and HOR, ORR activity.
(a) CV scan of MEAs with protonated or non-protonated ionomer. (b) CV scan of Pt/C as a function of the concentration of phosphoric acid. Each electrode (Pt/C) was conditioned in O2 saturated 0.1 M HClO4 solution before transferred into HClO4-H3PO4 mixture solution for ECSA measurement. (c) Effect of phosphoric acid on ECSA. Total concentration of HClO4-H3PO4 was kept the same as 0.5 M for the tests. (d) Effect of pentafluorophenyl phosphonic acid (PPA) on ECSA. Electrolyte for PPA: 0.1 M HClO4 + PPA. (e) HOR mass activity retention of catalysts in presence of phosphoric acid or PPA. Total used for PPA test. Red square: equivalent phenyl concentration of the protonated PtRu/C anode. Blue diamond: equivalent phenyl concentration of the non-protonated PtRu/C anode. (f) ORR mass activity retention of catalysts in presence of phosphoric acid or FPA. Total concentration of HClO4-H3PO4 was kept the same as 0.5 M for the phosphoric acid tests. 0.1 M HClO4 + FPA was used for FPA test. Red square: equivalent phenyl concentration of the protonated Pt/C cathode. Blue diamond: equivalent phenyl concentration of the non-protonated Pt/C cathode.
Extended Data Fig. 7 H2/air fuel cell performance of Nafion-based LT-PEMFCs at 100 °C as a function of RH.
i-V curve, power density and HFR of Nafion LT-PEMFC at 100 °C and 148 kPa (absolute) backpressure and high H2/air flows (500/500 sccm). Nafion MEA component: Nafion 211 membrane (25 µm thickness), Nafion ionomer, anode and cathode (TEC10E40E, Pt/C, 0.1 mgPt cm-2).
Extended Data Fig. 8 Effect of cathode catalyst loading on H2/air fuel cell performance.
Cathode catalyst: (a) HiSPEC 9100: Pt 60% on high surface area carbon (Johnson Matthey). (b) TEC10E40E: Pt 40% on high surface area carbon. (c) TEC10E20E: Pt 20% on high surface area carbon. The other MEA components: QAPOH-PA membrane (35 µm thick), anode catalyst (Pt-Ru/C, 0.5 mgPt cm-2), cathode catalyst (Pt/C, 0.1, 0.3, and 0.6 mgPt cm-2), and Nafion/PWN-1.8 ionomer (Nafion content: 0.5). The performance was measured at 160 °C under anhydrous conditions.
Extended Data Fig. 9 Comparison of H2/air fuel cell performance of different MEAs at 120 °C.
Protonated ionomer-bonded MEA: QAPOH-PA membrane (35 µm thickness), Nafion/ PWN-1.8 ionomer (Nafion content: 0.5), anode (Pt-Ru/C, 0.5 mgPt cm-2), and cathode (Pt/C, 0.3 mgPt cm-2). Commercial PA−PBI: PA-PBI membrane (50 µm thickness), PTFE binder, anode (Pt/C, 1.0 mgPt cm-2), and cathode (Pt-alloy, 0.75 mgPt cm-2). Nafion MEA: Nafion 211 membrane (25 µm thickness), Nafion ionomer, anode (Pt/C, 0.2 mgPt cm-2) and cathode (Pt/C, 0.3 mgPt cm-2).
Extended Data Fig. 10 Fuel cell performance of the protonated HT-PEMFC at 80 °C.
MEA components: QAPOH-PA membrane, anode catalyst (Pt-Ru/C, 0.5 mgPt cm–2), cathode catalyst (Pt/C, 0.6 mgPt cm–2), and Nafion/PWN-1.8 ionomer (Nafion content: 0.5). The performance was measured under anhydrous conditions.
Supplementary information
Supplementary Information
Supplementary Figs. 1–9 and Table 1.
Supplementary Data 1
Numerical data for Supplementary Figs. 2–8.
Source data
Source Data Fig. 1
Numerical source data for main Fig. 1.
Source Data Fig. 2
Numerical source data for main Fig. 2.
Source Data Fig. 3
Numerical source data for main Fig. 3.
Source Data Fig. 4
Numerical source data for main Fig. 4.
Source Data Fig. 5
Numerical source data for main Fig. 5.
Source Data Fig. 6
Numerical source data for main Fig. 6.
Source Data Extended Data Fig. 1
Numerical source data for Extended Data Fig. 1.
Source Data Extended Data Fig. 2
Numerical source data for Extended Data Fig. 2.
Source Data Extended Data Fig. 3
Numerical source data for Extended Data Fig. 3.
Source Data Extended Data Fig. 4
Numerical source data for Extended Data Fig. 4.
Source Data Extended Data Fig. 5
Numerical source data for Extended Data Fig. 5.
Source Data Extended Data Fig. 6
Numerical source data for Extended Data Fig. 6.
Source Data Extended Data Fig. 7
Numerical source data for Extended Data Fig. 7.
Source Data Extended Data Fig. 8
Numerical source data for Extended Data Fig. 8.
Source Data Extended Data Fig. 9
Numerical source data for Extended Data Fig. 9.
Source Data Extended Data Fig. 10
Numerical source data for Extended Data Fig. 10.
Rights and permissions
About this article
Cite this article
Lim, K.H., Lee, A.S., Atanasov, V. et al. Protonated phosphonic acid electrodes for high power heavy-duty vehicle fuel cells. Nat Energy 7, 248–259 (2022). https://doi.org/10.1038/s41560-021-00971-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41560-021-00971-x
This article is cited by
-
Recent Advances on PEM Fuel Cells: From Key Materials to Membrane Electrode Assembly
Electrochemical Energy Reviews (2023)
-
Low Pt loading for high-performance fuel cell electrodes enabled by hydrogen-bonding microporous polymer binders
Nature Communications (2022)