The role of LiO2 solubility in O2 reduction in aprotic solvents and its consequences for Li–O2 batteries


An Erratum to this article was published on 17 December 2014

This article has been updated


When lithium–oxygen batteries discharge, O2 is reduced at the cathode to form solid Li2O2. Understanding the fundamental mechanism of O2 reduction in aprotic solvents is therefore essential to realizing their technological potential. Two different models have been proposed for Li2O2 formation, involving either solution or electrode surface routes. Here, we describe a single unified mechanism, which, unlike previous models, can explain O2 reduction across the whole range of solvents and for which the two previous models are limiting cases. We observe that the solvent influences O2 reduction through its effect on the solubility of LiO2, or, more precisely, the free energy of the reaction LiO2* Li(sol)+ + O2(sol) + ion pairs + higher aggregates (clusters). The unified mechanism shows that low-donor-number solvents are likely to lead to premature cell death, and that the future direction of research for lithium–oxygen batteries should focus on the search for new, stable, high-donor-number electrolytes, because they can support higher capacities and can better sustain discharge.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: CVs demonstrating the significant effect that solvent DN and cation type have on O2 reduction.
Figure 2: CVs showing the first step of O2 reduction and plots of shifts of E°1 (O2/O2) with In[Li+] concentration for Me-Im and DMSO.
Figure 3: SER spectra demonstrating that at high voltages (low overpotentials) O2 and LiO2 species are observed on the electrode surface at short times in high- and low-DN solvents, respectively, to be replaced by Li2O2 over time.
Figure 4: Evidence from RRDE experiments showing the presence of O2 in solution in high-DN solvents (Me-Im and DMSO), some in intermediate-DN solvent (DME) and essentially none in low-DN CH3CN.
Figure 5: Schematic of the O2 reduction mechanism and plot showing how it is affected by DN and potential.
Figure 6: Potential versus time at a planar Au electrode in various O2-saturated aprotic solvents and 100 mM LiClO4.
Figure 7: SEM images showing the Li2O2 morphologies obtained in different solvents and at different potentials.

Change history

  • 20 November 2014

    In the version of this Article originally published, the author list was incorrectly ordered. Jean-Marie Tarascon should have appeared as the penultimate name. This has now been corrected in all online versions of the Article.


  1. 1

    Black, R., Adams, B. & Nazar, L. F. Non-aqueous and hybrid Li–O2 batteries. Adv. Energy Mater. 2, 801–815 (2012).

    CAS  Article  Google Scholar 

  2. 2

    Bruce, P. G., Freunberger, S. A., Hardwick, L. J. & Tarascon, J-M. Li–O2 and Li–S batteries with high energy storage. Nature Mater. 11, 19–29 (2012).

    CAS  Google Scholar 

  3. 3

    Choi, N-S. et al. Challenges facing lithium batteries and electrical double-layer capacitors. Angew. Chem. Int. Ed. 51, 9994–10024 (2012).

    CAS  Article  Google Scholar 

  4. 4

    Shao, Y. Y. et al. Electrocatalysts for nonaqueous lithium–air batteries: status, challenges, and perspective. ACS Catal. 2, 844–857 (2012).

    CAS  Google Scholar 

  5. 5

    Thackeray, M. M., Chan, M. K. Y., Trahey, L., Kirklin, S. & Wolverton, C. A vision for designing high energy, hybrid Li-ion/Li–O2 cells. J. Phys. Chem. Lett. 4, 3607–3611 (2013).

    CAS  Article  Google Scholar 

  6. 6

    Girishkumar, G., McCloskey, B., Luntz, A. C., Swanson, S. & Wilcke, W. Lithium–air battery: promise and challenges. J. Phys. Chem. Lett. 1, 2193–2203 (2010).

    CAS  Article  Google Scholar 

  7. 7

    Lu, Y-C. et al. Lithium–oxygen batteries: bridging mechanistic understanding and battery performance. Energy Environ. Sci. 6, 750–768 (2013).

    CAS  Article  Google Scholar 

  8. 8

    Garcia-Araez, N. & Novák, P. Critical aspects in the development of lithium–air batteries. J. Solid State Electrochem. 17, 1793–1807 (2013).

    CAS  Article  Google Scholar 

  9. 9

    Li, F., Zhang, T. & Zhou, H. Challenges of non-aqueous Li–O2 batteries: electrolytes, catalysts, and anodes. Energy Environ. Sci. 6, 1125–1141 (2013).

    CAS  Article  Google Scholar 

  10. 10

    Wang, Z-L., Xu, D., Xu, J-J. & Zhang, X-B. Oxygen electrocatalysts in metal–air batteries: from aqueous to nonaqueous electrolytes. Chem. Soc. Rev. (2014).

  11. 11

    McCloskey, B. D., Scheffler, R., Speidel, A., Girishkumar, G. & Luntz, A. C. On the mechanism of nonaqueous Li–O2 electrochemistry on C and its kinetic overpotentials: some implications for Li–air batteries. J. Phys. Chem. C 116, 23897–23905 (2012).

    CAS  Article  Google Scholar 

  12. 12

    Viswanathan, V. et al. Li–O2 kinetic overpotentials: Tafel plots from experiment and first-principles theory. J. Phys. Chem. Lett. 4, 556–560 (2013).

    CAS  Article  Google Scholar 

  13. 13

    Lu, J. et al. A nanostructured cathode architecture for low charge overpotential in lithium–oxygen batteries. Nature Commun. 4, 2383 (2013).

    Article  Google Scholar 

  14. 14

    Laoire, C. O., Mukerjee, S., Abraham, K. M., Plichta, E. J. & Hendrickson, M. A. Influence of nonaqueous solvents on the electrochemistry of oxygen in the rechargeable lithium–air battery. J. Phys. Chem. C 114, 9178–9186 (2010).

    CAS  Article  Google Scholar 

  15. 15

    Allen, C. J. et al. Oxygen reduction reactions in ionic liquids and the formulation of a general ORR mechanism for Li–air batteries. J. Phys. Chem. C 116, 20755–20764 (2012).

    CAS  Article  Google Scholar 

  16. 16

    Trahan, M. J., Mukerjee, S., Plichta, E. J., Hendrickson, M. A. & Abraham, K. M. Studies of Li–air cells utilizing dimethyl sulfoxide-based electrolyte. J. Electrochem. Soc. 160, A259–A267 (2013).

    CAS  Article  Google Scholar 

  17. 17

    Sharon, D. et al. Oxidation of dimethyl sulfoxide solutions by electrochemical reduction of oxygen. J. Phys. Chem. Lett. 4, 3115–3119 (2013).

    CAS  Article  Google Scholar 

  18. 18

    Herranz, J., Garsuch, A. & Gasteiger, H. A. Using rotating ring disc electrode voltammetry to quantify the superoxide radical stability of aprotic Li–air battery electrolytes. J. Phys. Chem. C 116, 19084–19094 (2012).

    CAS  Article  Google Scholar 

  19. 19

    Zhang, T. & Zhou, H. A reversible long-life lithium–air battery in ambient air. Nature Commun. 4, 1817 (2013).

    Article  Google Scholar 

  20. 20

    Walker, W. et al. A rechargeable Li–O2 battery using a lithium nitrate/N,N-dimethylactamide electrolyte. J. Am. Chem. Soc. 135, 2076–2079 (2013).

    CAS  Article  Google Scholar 

  21. 21

    Adams, B. D. et al. Current density dependence of peroxide formation in the Li–O2 battery and its effect on charge. Energy Environ. Sci. 6, 1772–1778 (2013).

    CAS  Google Scholar 

  22. 22

    Hummelshoj, J. S., Luntz, A. C. & Norskov, J. K. Theoretical evidence for low kinetic overpotentials in Li–O2 electrochemistry. J. Chem. Phys. 138, 034703–034712 (2013).

    CAS  Article  Google Scholar 

  23. 23

    Jung, H. G., Hassoun, J., Park, J. B., Sun, Y. K. & Scrosati, B. An improved high-performance lithium–air battery. Nature Chem. 4, 579–585 (2012).

    CAS  Article  Google Scholar 

  24. 24

    Mitchell, R. R., Gallant, B. M., Shao-Horn, Y. & Thompson, C. V. Mechanisms of morphological evolution of Li2O2 particles during electrochemical growth. J. Phys. Chem. Lett. 4, 1060–1064 (2013).

    CAS  Article  Google Scholar 

  25. 25

    Nasybulin, E. et al. Effects of electrolyte salts on the performance of Li–O2 batteries. J. Phys. Chem. C 117, 2635–2645 (2013).

    CAS  Article  Google Scholar 

  26. 26

    Nasybulin, E. et al. Electrocatalytic properties of poly(3,4-ethylenedioxythiophene) (PEDOT) in Li–O2 battery. Electrochem. Commun. 29, 63–66 (2013).

    CAS  Article  Google Scholar 

  27. 27

    Kang, S., Mo, Y., Ong, S. P. & Ceder, G. A facile mechanism for recharging Li2O2 in Li–O2 batteries. Chem. Mater. 25, 3328–3336 (2013).

    CAS  Article  Google Scholar 

  28. 28

    Suntivich, J. et al. Design principles for oxygen–reduction activity on perovskite oxide catalysts for fuel cells and metal–air batteries. Nature Chem. 3, 546–550 (2011).

    CAS  Article  Google Scholar 

  29. 29

    Younesi, R., Hahlin, M., Björefors, F., Johansson, P. & Edström, K. Li–O2 battery degradation by lithium peroxide (Li2O2): a model study. Chem. Mater. 25, 77–84 (2013).

    CAS  Article  Google Scholar 

  30. 30

    Trahey, L. et al. Synthesis, characterization, and structural modeling of high-capacity, dual functioning MnO2 electrode/electrocatalysts for Li–O2 cells. Adv. Energy Mater. 3, 75–84 (2013).

    CAS  Article  Google Scholar 

  31. 31

    Guo, Z. et al. Ordered hierarchical mesoporous/macroporous carbon: a high performance catalyst for rechargeable Li–O2 batteries. Adv. Mater. 25, 5668–5672 (2013).

    CAS  Article  Google Scholar 

  32. 32

    Li, L. & Manthiram, A. Dual-electrolyte lithium–air batteries: influence of catalyst, temperature, and solid-electrolyte conductivity on the efficiency and power density. J. Mater. Chem. A 1, 5121–5127 (2013).

    CAS  Article  Google Scholar 

  33. 33

    Zhang, T. et al. A novel high energy density rechargeable lithium/air battery. Chem. Commun. 46, 1661–1663 (2010).

    CAS  Article  Google Scholar 

  34. 34

    Xu, J-J., Wang, Z-L., Xu, D., Zhang, L-L. & Zhang, X-B. Tailoring deposition and morphology of discharge products towards high-rate and long-life lithium–oxygen batteries. Nature Commun. 4, 2438 (2013).

    Article  Google Scholar 

  35. 35

    Younesi, R. et al. Ether based electrolyte, LiB(CN)4 salt and binder degradation in the Li–O2 battery studied by hard X-ray photoelectron spectroscopy (HAXPES). J. Phys. Chem. C 116, 18597–18604 (2012).

    CAS  Article  Google Scholar 

  36. 36

    Yang, J. et al. Evidence for lithium superoxide-like species in the discharge product of a Li–O2 battery. Phys. Chem. Chem. Phys. 15, 3764–3771 (2013).

    CAS  Article  Google Scholar 

  37. 37

    Lu, J. et al. Synthesis and characterization of uniformly dispersed Fe3O4/Fe nanocomposite on porous carbon: application for rechargeable Li–O2 batteries. RSC Adv. 3, 8276–8285 (2013).

    CAS  Article  Google Scholar 

  38. 38

    Veith, G. M., Nanda, J., Delmau, L. H. & Dudney, N. J. Influence of lithium salts on the discharge chemistry of Li–air cells. J. Phys. Chem. Lett. 3, 1242–1247 (2012).

    CAS  Article  Google Scholar 

  39. 39

    Pearson, R. G. Hard and soft acids and bases. J. Am. Chem. Soc. 85, 3533–3539 (1963).

    CAS  Article  Google Scholar 

  40. 40

    Sawyer, D. T., Chlericato, G., Angelis, C. T., Nanni, E. J. & Tsuchiya, T. Effects of media and electrode materials on the electrochemical reduction of dioxygen. Anal. Chem. 54, 1720–1724 (1982).

    CAS  Article  Google Scholar 

  41. 41

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

    Article  Google Scholar 

  42. 42

    Nissim, R., Batchelor-McAuley, C., Li, Q. & Compton, R. G. The anthraquinone mediated one-electron reduction of oxygen in acetonitrile. J. Electroanal. Chem. 681, 44–48 (2012).

    CAS  Article  Google Scholar 

  43. 43

    Laoire, C. O., Mukerjee, S., Abraham, K. M., Plichta, E. J. & Hendrickson, M. A. Elucidating the mechanism of oxygen reduction for lithium–air battery applications. J. Phys. Chem. C 113, 20127–20134 (2009).

    CAS  Article  Google Scholar 

  44. 44

    Lu, Y. C., Gasteiger, H. A., Parent, M. C., Chiloyan, V. & Shao-Horn, Y. The influence of catalysts on discharge and charge voltages of rechargeable Li–oxygen batteries. Electrochem. Solid-State Lett. 13, A69–A72 (2010).

    CAS  Article  Google Scholar 

  45. 45

    Bard, A. J. & Faulkner, L. R. Electrochemical Methods: Fundamentals and Applications 2nd edn (Wiley, 2001).

    Google Scholar 

  46. 46

    Peng, Z. et al. Oxygen reactions in a non-aqueous Li+ electrolyte. Angew. Chem. Int. Ed. 50, 6351–6355 (2011).

    CAS  Article  Google Scholar 

  47. 47

    Pasgreta, E. et al. Ligand-exchange processes on solvated lithium cations: DMSO and water/DMSO mixtures. ChemPhysChem 8, 1315–1320 (2007).

    CAS  Article  Google Scholar 

  48. 48

    Bryantsev, V. Calculation of solvation free energies of Li+ and O2 ions and neutral lithium–oxygen compounds in acetonitrile using mixed cluster/continuum models. Theor. Chem. Acc. 131, 1–11 (2012).

    CAS  Article  Google Scholar 

  49. 49

    Das, U., Lau, K. C., Redfern, P. C. & Curtiss, L. A. Structure and stability of lithium superoxide clusters and relevance to Li–O2 batteries. J. Phys. Chem. Lett. 5, 813–819 (2014).

    CAS  Article  Google Scholar 

  50. 50

    Bryantsev, V. S. et al. Predicting solvent stability in aprotic electrolyte Li–air batteries: nucleophilic substitution by the superoxide anion radical (O2). J. Phys. Chem. A 115, 12399–12409 (2011).

    CAS  Article  Google Scholar 

  51. 51

    Bryantsev, V. S., Blanco, M. & Faglioni, F. Stability of lithium superoxide LiO2 in the gas phase: computational study of dimerization and disproportionation reactions. J. Phys. Chem. A 114, 8165–8169 (2010).

    CAS  Article  Google Scholar 

  52. 52

    Horstmann, B. et al. Rate-dependent morphology of Li2O2 growth in Li–O2 batteries. J. Phys. Chem. Lett. 4, 4217–4222 (2013).

    CAS  Article  Google Scholar 

  53. 53

    Luntz, A. C. et al. Tunneling and polaron charge transport through Li2O2 in Li–O2 batteries. J. Phys. Chem. Lett. 4, 3494–3499 (2013).

    CAS  Article  Google Scholar 

Download references


P.G.B. acknowledges financial support from the Engineering and Physical Sciences Research Council (including the SUPERGEN programme). S.A.F. acknowledges financial support from the Austrian Federal Ministry of Economy, Family and Youth and the Austrian National Foundation for Research, Technology and Development as well as the Austrian Science Fund (FWF): P26870-N19. K.D. thanks the UK EPSRC for funding and the European Union project FAMOS (FP7 ICT, contract no. 317744). The authors thank D. Larcher for discussions.

Author information




L.J. and C.L. designed and performed electrochemical and Raman spectroscopy experiments and analysed the data. Z.L. discharged and performed microscopy of Li2O2 on high-surface-area cathodes. P.C.A. and B.B.P. built and maintained the Raman microscope and contributed to the Raman measurements and analysis. Y.C. performed the UV–vis spectroscopy experiments and analysed the data. P.G.B., L.J., Y.C. and S.F. interpreted the data. P.G.B. wrote the paper with contributions from L.J. The project was supervised by P.G.B., J-M.T. and K.D.

Corresponding author

Correspondence to Peter G. Bruce.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 1674 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Johnson, L., Li, C., Liu, Z. et al. The role of LiO2 solubility in O2 reduction in aprotic solvents and its consequences for Li–O2 batteries. Nature Chem 6, 1091–1099 (2014).

Download citation

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing