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Triarylmethyl cation redox mediators enhance Li–O2 battery discharge capacities

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Abstract

A major impediment to Li–O2 battery commercialization is the low discharge capacities resulting from electronically insulating Li2O2 film growth on carbon electrodes. Redox mediation offers an effective strategy to drive oxygen chemistry into solution, avoiding surface-mediated Li2O2 film growth and extending discharge lifetimes. As such, the exploration of diverse redox mediator classes can aid the development of molecular design criteria. Here we report a class of triarylmethyl cations that are effective at enhancing discharge capacities up to 35-fold. Surprisingly, we observe that redox mediators with more positive reduction potentials lead to larger discharge capacities because of their improved ability to suppress the surface-mediated reduction pathway. This result provides important structure–property relationships for future improvements in redox-mediated O2/Li2O2 discharge capacities. Furthermore, we applied a chronopotentiometry model to investigate the zones of redox mediator standard reduction potentials and the concentrations needed to achieve efficient redox mediation at a given current density. We expect this analysis to guide future redox mediator exploration.

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Fig. 1: Chemical structures and proposed mechanistic overview of triarylmethy cation redox mediation.
Fig. 2: Computational screening of redox mediators.
Fig. 3: Cyclic voltammograms of various redox mediators.
Fig. 4: Battery discharge curves for Li–O2 cells prepared with 1 M LiOTF in TEGDME and an LFP anode.
Fig. 5: Correspondence of \(E_{{\mathrm{R}}^+/{\mathrm{R}}^{\bullet}}\) and effective outer-sphere redox mediation.

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Data availability

Source data for figures in the main text have been uploaded to the Figshare public data repository and can be accessed at https://doi.org/10.6084/m9.figshare.21719882 (ref. 61). Source data are provided with this paper.

Code availability

All computer codes used in this manuscript are available from the cited references.

References

  1. Kwak, W.-J. et al. Lithium-oxygen batteries and related systems: potential, status and future. Chem. Rev. 120, 6626–6683 (2020).

    CAS  PubMed  Google Scholar 

  2. Aurbach, D., McCloskey, B. D., Nazar, L. F. & Bruce, P. G. Advances in understanding mechanisms underpinning lithium–air batteries. Nat. Energy 1, 16128 (2016).

    CAS  Google Scholar 

  3. Viswanathan, V. et al. Electrical conductivity in Li2O2 and its role in determining capacity limitations in non-aqueous Li-O2 batteries. J. Chem. Phys. 135, 214704 (2011).

    CAS  PubMed  Google Scholar 

  4. Aetukuri, N. B. et al. Solvating additives drive solution-mediated electrochemistry and enhance toroid growth in non-aqueous Li–O2 batteries. Nat. Chem. 7, 50–56 (2015).

    CAS  PubMed  Google Scholar 

  5. Burke, C. M., Pande, V., Khetan, A., Viswanathan, V. & McCloskey, B. D. Enhancing electrochemical intermediate solvation through electrolyte anion selection to increase nonaqueous Li-O2 battery capacity. Proc. Natl Acad. Sci. USA 112, 9293–9298 (2015).

    CAS  PubMed  PubMed Central  Google Scholar 

  6. Zhang, Y. et al. Potential-dependent generation of O2 and LiO2 and their critical roles in O2 reduction to Li2O2 in aprotic Li-O2 batteries. J. Phys. Chem. C 120, 3690–3698 (2016).

    CAS  Google Scholar 

  7. Dai, A., Li, Q., Liu, T., Amine, K. & Lu, J. Fundamental understanding of water-induced mechanisms in Li-O2 batteries: recent developments and perspectives. Adv. Mater. 31, 1805602 (2019).

    Google Scholar 

  8. Han, X.-B. & Ye, S. Structural design of oxygen reduction redox mediators (ORRMs) based on anthraquinone (AQ) for the Li-O2 battery. ACS Catal. 10, 9790–9803 (2020).

    CAS  Google Scholar 

  9. Gao, X., Chen, Y., Johnson, L. & Bruce, P. G. Erratum: promoting solution phase discharge in Li–O2 batteries containing weakly solvating electrolyte solutions. Nat. Mater. 15, 918 (2016).

    CAS  PubMed  Google Scholar 

  10. Matsuda, S., Hashimoto, K. & Nakanishi, S. Efficient Li2O2 formation via aprotic oxygen reduction reaction mediated by quinone derivatives. J. Phys. Chem. C 118, 18397–18400 (2014).

    CAS  Google Scholar 

  11. Sun, D. et al. A solution-phase bifunctional catalyst for lithium-oxygen batteries. J. Am. Chem. Soc. 136, 8941–8946 (2014).

    CAS  PubMed  Google Scholar 

  12. Zhang, Y. et al. High-capacity and high-rate discharging of a coenzyme Q10-catalyzed Li-O2 battery. Adv. Mater. 30, 1705571 (2018).

    Google Scholar 

  13. Ko, Y. et al. Biological redox mediation in electron transport chain of bacteria for oxygen reduction reaction catalysts in lithium-oxygen batteries. Adv. Funct. Mater. 29, 1805623 (2019).

    Google Scholar 

  14. Lacey, M. J., Frith, J. T. & Owen, J. R. A redox shuttle to facilitate oxygen reduction in the lithium air battery. Electrochem. Commun. 26, 74–76 (2013).

    CAS  Google Scholar 

  15. Yang, L., Frith, J. T., Garcia-Araez, N. & Owen, J. R. A new method to prevent degradation of lithium-oxygen batteries: reduction of superoxide by viologen. Chem. Commun. 51, 1705–1708 (2015).

    CAS  Google Scholar 

  16. Hwang, C. et al. Biomimetic superoxide disproportionation catalyst for anti-aging lithium-oxygen batteries. ACS Nano 13, 9190–9197 (2019).

    CAS  PubMed  Google Scholar 

  17. Lee, D. et al. Direct observation of redox mediator-assisted solution-phase discharging of Li-O2 battery by liquid-phase transmission electron microscopy. J. Am. Chem. Soc. 141, 8047–8052 (2019).

    CAS  PubMed  Google Scholar 

  18. Kwak, W.-J. et al. Understanding the behavior of Li-oxygen cells containing LiI. J. Mater. Chem. A 3, 8855–8864 (2015).

    CAS  Google Scholar 

  19. Kwak, W.-J. et al. Li-O2 cells with LiBr as an electrolyte and a redox mediator. Energy Environ. Sci. 9, 2334–2345 (2016).

    CAS  Google Scholar 

  20. Sharon, D. et al. Catalytic behavior of lithium nitrate in Li-O2 cells. ACS Appl. Mater. Interfaces 7, 16590–16600 (2015).

    CAS  PubMed  Google Scholar 

  21. Liu, T. et al. Cycling Li-O2 batteries via LiOH formation and decomposition. Science 350, 530–533 (2015).

    CAS  PubMed  Google Scholar 

  22. Yang, H., Wang, Q., Zhang, R., Trimm, B. D. & Whittingham, M. S. The electrochemical behaviour of TTF in Li-O2 batteries using a TEGDME-based electrolyte. Chem. Commun. 52, 7580–7583 (2016).

    CAS  Google Scholar 

  23. Bergner, B. J., Schürmann, A., Peppler, K., Garsuch, A. & Janek, J. TEMPO: a mobile catalyst for rechargeable Li-O2 batteries. J. Am. Chem. Soc. 136, 15054–15064 (2014).

    CAS  PubMed  Google Scholar 

  24. Lim, H.-D. et al. Rational design of redox mediators for advanced Li–O2 batteries. Nat. Energy 1, 16066 (2016).

    CAS  Google Scholar 

  25. Zhang, C. et al. A comparative study of redox mediators for improved performance of Li-oxygen batteries. Adv. Energy Mater. 10, 2000201 (2020).

    CAS  Google Scholar 

  26. Gao, X., Chen, Y., Johnson, L. R., Jovanov, Z. P. & Bruce, P. G. A rechargeable lithium–oxygen battery with dual mediators stabilizing the carbon cathode. Nat. Energy 2, 17118 (2017).

    CAS  Google Scholar 

  27. Weerasooriya, R. B. et al. Kinetics of hydride transfer from catalytic metal-free hydride donors to CO2. J. Phys. Chem. Lett. 12, 2306–2311 (2021).

    CAS  PubMed  Google Scholar 

  28. Lim, C.-H. et al. Benzimidazoles as metal-free and recyclable hydrides for CO2 reduction to formate. J. Am. Chem. Soc. 141, 272–280 (2019).

    CAS  PubMed  Google Scholar 

  29. Zoric, M. R., Kadel, U. P. & Glusac, K. D. Cocatalysis: role of organic cations in oxygen evolution reaction on oxide electrodes. ACS Appl. Mater. Interfaces 10, 26825–26829 (2018).

    CAS  PubMed  Google Scholar 

  30. Ilic, S., Pandey Kadel, U., Basdogan, Y., Keith, J. A. & Glusac, K. D. Thermodynamic hydricities of biomimetic organic hydride donors. J. Am. Chem. Soc. 140, 4569–4579 (2018).

    CAS  PubMed  Google Scholar 

  31. Ilic, S., Alherz, A., Musgrave, C. B. & Glusac, K. D. Thermodynamic and kinetic hydricities of metal-free hydrides. Chem. Soc. Rev. 47, 2809–2836 (2018).

    CAS  PubMed  Google Scholar 

  32. Yang, X. et al. Mechanistic studies of electrode-assisted catalytic oxidation by flavinium and acridinium cations. ACS Catal. 4, 2635–2644 (2014).

    CAS  Google Scholar 

  33. Zoric, M. R. et al. Conformational flexibility of xanthene-based covalently linked dimers. J. Phys. Org. Chem. 29, 505–513 (2016).

    CAS  Google Scholar 

  34. Mirzakulova, E. et al. Electrode-assisted catalytic water oxidation by a flavin derivative. Nat. Chem. 4, 794–801 (2012).

    PubMed  Google Scholar 

  35. Ilic, S., Alherz, A., Musgrave, C. B. & Glusac, K. D. Importance of proton-coupled electron transfer in cathodic regeneration of organic hydrides. Chem. Commun. 55, 5583–5586 (2019).

    CAS  Google Scholar 

  36. Hogan, D. T. & Sutherland, T. C. Modern spin on the electrochemical persistence of heteroatom-bridged triphenylmethyl-type radicals. J. Phys. Chem. Lett. 9, 2825–2829 (2018).

    CAS  PubMed  Google Scholar 

  37. Erabi, T., Asahara, M., Miyamoto, M., Goto, K. & Wada, M. 9-Phenylxanthen-9-ylium and 9-phenylthioxanthen-9-ylium ions: comparison of o- and p-substitutions in the 9-phenyl group by cyclic voltammetry and visible spectra. Bull. Chem. Soc. Jpn 75, 1325–1332 (2002).

    CAS  Google Scholar 

  38. Ilic, S., Brown, E. S., **e, Y., Maldonado, S. & Glusac, K. D. Sensitization of p-GaP with monocationic dyes: the effect of dye excited-state lifetime on hole injection efficiencies. J. Phys. Chem. C 120, 3145–3155 (2016).

    CAS  Google Scholar 

  39. Hapiot, P., Moiroux, J. & Saveant, J. M. Electrochemistry of NADH/NAD+ analogs. A detailed mechanistic kinetic and thermodynamic analysis of the 10-methylacridan/10-methylacridinium couple in acetonitrile. J. Am. Chem. Soc. 112, 1337–1343 (1990).

    CAS  Google Scholar 

  40. Gostowski, R. C., Bailey, T., Bonner, S. D., Emrich, E. E. & Steelman, S. L. Steric hindrance effects on bimolecular coupling rate constants of carbon-centered radicals. J. Phys. Org. Chem. 13, 735–739 (2000).

    CAS  Google Scholar 

  41. Chase, M. W. NIST-JANAF thermochemical tables. J. Phys. Chem. Ref. Data 9, 1510 (1998).

    Google Scholar 

  42. Vasudevan, D. & Wendt, H. Electroreduction of oxygen in aprotic media. J. Electroanal. Chem. 392, 69–74 (1995).

    Google Scholar 

  43. Andrieux, C. P., Dumas-Bouchiat, J. M. & Saveant, J. M. Homogeneous redox catalysis of electrochemical reactions: Part I. Introduction. J. Electroanal. Chem. Interfacial Electrochem. 87, 39–53 (1978).

    CAS  Google Scholar 

  44. Andrieux, C. P., Blocman, C., Dumas-Bouchiat, J. M. & Saveant, J. M. Heterogeneous and homogeneous electron transfers to aromatic halides. An electrochemical redox catalysis study in the halobenzene and halopyridine series. J. Am. Chem. Soc. 101, 3431–3441 (1979).

    CAS  Google Scholar 

  45. Andrieux, C. P., Hapiot, P. & Sa Véant, J. M. Electron transfer coupling of diffusional pathways. Homogeneous redox catalysis of dioxygen reduction by the methylviologen cation radical in acidic dimethylsulfoxide. J. Electroanal. Chem. Interfacial Electrochem. 189, 121–133 (1985).

    CAS  Google Scholar 

  46. Bawol, P. P., Thimm, J. H. & Baltruschat, H. Unraveling the mechanism of the solution-mediated oxygen reduction in metal-O2 batteries: the importance of ion association. ChemElectroChem 6, 6038–6049 (2019).

    CAS  Google Scholar 

  47. Lu, J. et al. A lithium–oxygen battery based on lithium superoxide. Nature 529, 377–382 (2016).

    CAS  PubMed  Google Scholar 

  48. Wu, S. et al. Revealing the catalytic pathway of a quinone-mediated oxygen reduction reaction in aprotic Li-O2 batteries. Chem. Commun. 58, 1025–1028 (2022).

    CAS  Google Scholar 

  49. Zhu, Y. G. et al. Synergistic oxygen reduction of dual redox catalysts boosting the power of lithium-air battery. Phys. Chem. Chem. Phys. 20, 27930–27936 (2018).

    CAS  PubMed  Google Scholar 

  50. Kwabi, D. G. et al. Controlling solution-mediated reaction mechanisms of oxygen reduction using potential and solvent for aprotic lithium-oxygen batteries. J. Phys. Chem. Lett. 7, 1204–1212 (2016).

    CAS  PubMed  Google Scholar 

  51. Laursen, B. W. & Krebs, F. C. Synthesis of a triazatriangulenium salt. Angew. Chem. Int. Ed. 39, 3432–3434 (2000).

    CAS  Google Scholar 

  52. Padhi, A. K., Nanjundaswamy, K. S. & Goodenough, J. B. Phospho‐olivines as positive‐electrode materials for rechargeable lithium batteries. J. Electrochem. Soc. 144, 1188 (1997).

    CAS  Google Scholar 

  53. McCloskey, B. D., Bethune, D. S., Shelby, R. M., Girishkumar, G. & Luntz, A. C. Solvents’ critical role in nonaqueous lithium-oxygen battery electrochemistry. J. Phys. Chem. Lett. 2, 1161–1166 (2011).

    CAS  PubMed  Google Scholar 

  54. Hartmann, P. et al. A comprehensive study on the cell chemistry of the sodium superoxide (NaO2) battery. Phys. Chem. Chem. Phys. 15, 11661–11672 (2013).

    CAS  PubMed  Google Scholar 

  55. Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E. & Robb, M. A. Gaussian 09, Revision A.02 (Gaussian, 2016).

  56. Becke, A. D. Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A 38, 3098–3100 (1988).

    CAS  Google Scholar 

  57. Lee, C., Yang, W. & Parr, R. G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 37, 785–789 (1988).

    CAS  Google Scholar 

  58. McLean, A. D. & Chandler, G. S. Contracted Gaussian basis sets for molecular calculations. I. Second row atoms, Z = 11–18. J. Chem. Phys. 72, 5639–5648 (1980).

    CAS  Google Scholar 

  59. Tomasi, J. & Persico, M. Molecular interactions in solution: an overview of methods based on continuous distributions of the solvent. Chem. Rev. 94, 2027–2094 (1994).

    CAS  Google Scholar 

  60. Delahay, P., Mattax, C. C. & Berzins, T. Theory of voltammetry at constant current. IV. Electron transfer followed by chemical reaction. J. Am. Chem. Soc. 76, 5319–5324 (1954).

    CAS  Google Scholar 

  61. Askins, E. J. et al. Triarylmethyl cation redox mediators enhance Li-O2 battery discharge capacities. figshare https://doi.org/10.6084/m9.figshare.21719882 (2023).

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Acknowledgements

K.D.G. acknowledges the support of the National Science Foundation and grant NSF 1954298. K.A. and L.A.C. thank the US Department of Energy for support under contract no. DE-AC02-06CH11357 from the Vehicle Technologies Office, which helped support the work done at ANL. We gratefully acknowledge the computing resources provided on Bebop, a high-performance computing cluster operated by the Laboratory Computing Resource Center (LCRC) at ANL. We also acknowledge the Electron Microscopy Core (EMC) at UIC’s Research Resource’s Center (RRC), where a substantial amount of post-discharge characterization was performed.

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Authors

Contributions

E.J.A., M.R.Z., R.A., K.A. and K.D.G. helped with the conception of this manuscript. E.J.A., M.R.Z. and L.A.C. performed the DFT evaluations and analysis of redox mediators. E.J.A. performed the CV experiments and analysis. E.J.A. performed the battery discharge experiments and analysis. E.J.A. and R.A. performed the post-discharge product characterization. E.J.A. and M.L. performed the DEMS experiments and analysis. E.J.A. and K.D.G. analysed crucial data and wrote the manuscript.

Corresponding author

Correspondence to Ksenija D. Glusac.

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Nature Chemistry thanks Javier Carrasco, Kisuk Kang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary discussion, Figs. 1–17, scheme 1 and Tables 1–6.

Supplementary Data 1

Additional redox mediator CV data.

Supplementary Data 2

CV and UV–vis titration data for chemically and electrochemically derived RO–OR species.

Supplementary Data 3

CV data for outer-sphere redox mediation experiments.

Supplementary Data 4

CV data for the Li+-coupling of outer-sphere redox mediation.

Supplementary Data 5

Scan rate-dependent peak CV current data.

Supplementary Data 6

CV data fitting in Ar-purged solutions.

Supplementary Data 7

CV data fitting in O2-saturated solutions.

Supplementary Data 8

Battery discharge data for Li anodes.

Supplementary Data 9

R+ concentration-dependent battery discharge data with LFP anodes.

Supplementary Data 10

R+ concentration-dependent battery discharge data with Li anodes.

Supplementary Data 11

Baseline and redox-mediated DEMS data.

Supplementary Data 12

Post discharge Raman data.

Supplementary Data 13

Data for comparison between extracted bimolecular rate constants and redox-mediated battery discharge capacity.

Supplementary Data 14

Unprocessed SEM image from pristine electrode.

Supplementary Data 15

Unprocessed SEM image from discharged electrode.

Supplementary Data 16

Unprocessed SEM image from discharged electrode.

Supplementary Data 17

Unprocessed SEM image from discharged electrode.

Supplementary Data 18

Unprocessed SEM image from discharged electrode.

Supplementary Data 19

Unprocessed SEM image from discharged electrode.

Supplementary Data 20

Unprocessed SEM image from discharged electrode.

Supplementary Data 21

Unprocessed SEM image from discharged electrode.

Source data

Source Data Fig. 2

Output energies (Ha) from DFT calculations of R+, R and RO–OR.

Source Data Fig. 3

CVs presented in Fig. 3.

Source Data Fig. 4

Battery discharge curves presented in Fig. 4.

Source Data Fig. 5

Extracted kinetic rate constants and battery discharge values compared in Fig. 5.

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Askins, E.J., Zoric, M.R., Li, M. et al. Triarylmethyl cation redox mediators enhance Li–O2 battery discharge capacities. Nat. Chem. 15, 1247–1254 (2023). https://doi.org/10.1038/s41557-023-01268-0

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