Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Gradient Li-rich oxide cathode particles immunized against oxygen release by a molten salt treatment


Lithium-rich transition metal oxide (Li1+XM1−XO2) cathodes have high energy density above 900 Wh kg−1 due to hybrid anion- and cation-redox (HACR) contributions, but critical issues such as oxygen release and voltage decay during cycling have prevented their application for years. Here we show that a molten molybdate-assisted LiO extraction at 700 °C creates lattice-coherent but depth (r)-dependent Li1+X(r)M1−X(r)O2 particles with a Li-rich (X ≈ 0.2) interior, a Li-poor (X ≈ −0.05) surface and a continuous gradient in between. The gradient Li-rich single crystals eliminate the oxygen release to the electrolyte and, importantly, still allow stable oxygen redox contributions within. Both the metal valence states and the crystal structure are well maintained during cycling. The gradient HACR cathode displays a specific density of 843 Wh kg−1 after 200 cycles at 0.2C and 808 Wh kg−1 after 100 cycles at 1C, with very little oxygen release and consumption of electrolyte. This high-temperature immunization treatment can be generalized to leach other elements to avoid unexpected surface reactions in batteries.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Redox behaviour and structural design of Li1+X(r)M1−X(r)O2 particles with a continuous gradient from the Li-rich bulk to the Li-poor surface.
Fig. 2: Characterizations of Li1+X(r)M1−X(r)O2 single crystals and quantification of X(r).
Fig. 3: Electrochemical behaviours of the pristine Li1.20Mn0.48Co0.16Ni0.16O2 and Li1+X(r)M1−X(r)O2.
Fig. 4: Valence profiles of oxygen and M in gradient LX(r)MO in the charge process.
Fig. 5: Mn oxidation states and structural damage after cycling.
Fig. 6: Stabilization of Li diffusivity and full-cell cycling.

Data availability

The data that support the plots in this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. 1.

    Xue, W. et al. Intercalation-conversion hybrid cathodes enabling Li–S full-cell architectures with jointly superior gravimetric and volumetric energy densities. Nat. Energy 4, 374–382 (2019).

    Google Scholar 

  2. 2.

    Zhu, Z. et al. Anion-redox nanolithia cathodes for Li-ion batteries. Nat. Energy 1, 16111 (2016).

    Google Scholar 

  3. 3.

    Qiao, Y., Jiang, K. Z., Deng, H. & Zhou, H. S. A high-energy-density and long-life lithium-ion battery via reversible oxide–peroxide conversion. Nat. Catal. 2, 1035–1044 (2019).

    Google Scholar 

  4. 4.

    Kim, S., Cho, W., Zhang, X., Oshima, Y. & Choi, J. W. A stable lithium-rich surface structure for lithium-rich layered cathode materials. Nat. Commun. 7, 13598 (2016).

    Google Scholar 

  5. 5.

    Luo, K. et al. One-pot synthesis of lithium-rich cathode material with hierarchical morphology. Nano Lett. 16, 7503–7508 (2016).

    Google Scholar 

  6. 6.

    Yu, H. J. & Zhou, H. S. High-energy cathode materials (Li2MnO3–LiMO2) for lithium-ion batteries. J. Phys. Chem. Lett. 4, 1268–1280 (2013).

    Google Scholar 

  7. 7.

    Yu, H. J. et al. High-energy ‘composite’ layered manganese-rich cathode materials via controlling Li2MnO3 phase activation for lithium-ion batteries. Phys. Chem. Chem. Phys. 14, 6584–6595 (2012).

    Google Scholar 

  8. 8.

    Ye, D. L. et al. Understanding the origin of Li2MnO3 activation in Li-rich cathode materials for lithium-ion batteries. Adv. Fun. Mater. 25, 7488–7496 (2015).

    Google Scholar 

  9. 9.

    Seo, D.-H. et al. The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials. Nat. Chem. 8, 692–697 (2016).

    Google Scholar 

  10. 10.

    Yan, P. et al. Injection of oxygen vacancies in the bulk lattice of layered cathodes. Nat. Nanotechnol. 14, 602–608 (2019).

    Google Scholar 

  11. 11.

    Lee, E. & Persson, K. A. Structural and chemical evolution of the layered Li-excess LixMnO3 as a function of Li content from first-principles calculations. Adv. Energy Mater. 4, 1400498 (2014).

    Google Scholar 

  12. 12.

    Luo, K. et al. Charge-compensation in 3d-transition-metal-oxide intercalation cathodes through the generation of localized electron holes on oxygen. Nat. Chem. 8, 684–691 (2016).

    Google Scholar 

  13. 13.

    Lee, J. Y. et al. Mitigating oxygen loss to improve the cycling performance of high capacity cation-disordered cathode materials. Nat. Commun. 8, 981 (2017).

    Google Scholar 

  14. 14.

    Chen, H. R. & Islam, M. S. Lithium extraction mechanism in Li-rich Li2MnO3 involving oxygen hole formation and dimerization. Chem. Mater. 28, 6656–6663 (2016).

    Google Scholar 

  15. 15.

    Singer, A. et al. Nucleation of dislocations and their dynamics in layered oxide cathode materials during battery charging. Nat. Energy 3, 641–647 (2018).

    Google Scholar 

  16. 16.

    Hu, E. Y. et al. Evolution of redox couples in Li- and Mn-rich cathode materials and mitigation of voltage fade by reducing oxygen release. Nat. Energy 3, 690–698 (2018).

    Google Scholar 

  17. 17.

    Hy, S., Felix, F., Rick, J., Su, W. N. & Hwang, B. J. Direct in situ observation of Li2O evolution on Li-rich high-capacity cathode material, Li[NixLi(1−2x)/3Mn(2−x)/3]O2 (0 ≤ x ≤0.5). J. Am. Chem. Soc. 136, 999–1007 (2014).

    Google Scholar 

  18. 18.

    Tran, N. et al. Mechanisms associated with the “plateau” observed at high voltage for the overlithiated Li1.12(Ni0.425Mn0.425Co0.15)0.88O2 system. Chem. Mater. 20, 4815–4825 (2008).

    Google Scholar 

  19. 19.

    Yan, P. F. et al. Probing the degradation mechanism of Li2MnO3 cathode for Li-ion batteries. Chem. Mater. 27, 975–982 (2015).

    Google Scholar 

  20. 20.

    Guo, S. H. et al. Surface coating of lithium-manganese-rich layered oxides with delaminated MnO2 nanosheets as cathode materials for Li-ion batteries. J. Mater. Chem. A 2, 4422–4428 (2014).

    Google Scholar 

  21. 21.

    Zheng, F. H. et al. Nanoscale surface modification of lithium-rich layered-oxide composite cathodes for suppressing voltage fade. Angew. Chem. Int. Ed. 54, 13058–13062 (2015).

    Google Scholar 

  22. 22.

    Kang, S. H., Johnson, C. S., Vaughey, J. T., Amine, K. & Thackeray, M. M. The effects of acid treatment on the electrochemical properties of 0.5 Li2MnO3 ∙ 0.5 LiNi0.44Co0.25Mn0.31O2 electrodes in lithium cells. J. Electrochem. Soc. 153, A1186–A1192 (2006).

    Google Scholar 

  23. 23.

    Qiu, B. et al. Gas–solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries. Nat. Commun. 7, 12108 (2016).

    Google Scholar 

  24. 24.

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

    Google Scholar 

  25. 25.

    Freunberger, S. A. et al. Reactions in the rechargeable lithium–O2 battery with alkyl carbonate electrolytes. J. Am. Chem. Soc. 133, 8040–8047 (2011).

    Google Scholar 

  26. 26.

    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).

    Google Scholar 

  27. 27.

    Sun, Y.-K. et al. Nanostructured high-energy cathode materials for advanced lithium batteries. Nat. Mater. 11, 942–947 (2012).

    Google Scholar 

  28. 28.

    Lim, B. B. et al. Advanced concentration gradient cathode material with two-slope for high-energy and safe lithium batteries. Adv. Funct. Mater. 25, 4673–4680 (2015).

    Google Scholar 

  29. 29.

    Nakamura, T. et al. Defect chemical studies on oxygen release from the Li-rich cathode material Li1.2Mn0.6Ni0.2O2−δ. J. Mater. Chem. A 7, 5009–5019 (2019).

    Google Scholar 

  30. 30.

    Cho, Y., Oh, P. & Cho, J. A new type of protective surface layer for high-capacity Ni-based cathode materials: nanoscaled surface pillaring layer. Nano Lett. 13, 1145–1152 (2013).

    Google Scholar 

  31. 31.

    Loomer, D. B., Al, T. A., Weaver, L. & Cogswell, S. Manganese valence imaging in Mn minerals at the nanoscale using STEM-EELS. Am. Mineral. 92, 72–79 (2007).

    Google Scholar 

  32. 32.

    Li, Z. P. et al. Interface and surface cation stoichiometry modified by oxygen vacancies in epitaxial manganite films. Adv. Funct. Mater. 22, 4312–4321 (2012).

    Google Scholar 

  33. 33.

    Lu, J. et al. Nanoscale coating of LiMO2 (M = Ni, Co, Mn) nanobelts with Li+-conductive Li2TiO3: toward better rate capabilities for Li-ion batteries. J. Am. Chem. Soc. 135, 1649–1652 (2013).

    Google Scholar 

  34. 34.

    Qiao, R. et al. Direct experimental probe of the Ni(II)/Ni(III)/Ni(IV) redox evolution in LiNi0.5Mn1.5O4 electrodes. J. Phys. Chem. C. 119, 27228–27233 (2015).

    Google Scholar 

  35. 35.

    Luo, K. et al. Anion redox chemistry in the cobalt free 3d transition metal oxide intercalation electrode Li[Li0.2Ni0.2Mn0.6]O2. J. Am. Chem. Soc. 138, 11211–11218 (2016).

    Google Scholar 

  36. 36.

    Oishi, M. et al. Direct observation of reversible oxygen anion redox reaction in Li-rich manganese oxide, Li2MnO3, studied by soft X-ray absorption spectroscopy. J. Mater. Chem. A 4, 9293–9302 (2016).

    Google Scholar 

  37. 37.

    Dai, K. H. et al. High reversibility of lattice oxygen redox quantified by direct bulk probes of both anionic and cationic redox reactions. Joule 3, 518–541 (2019).

    Google Scholar 

  38. 38.

    Qiao, R. M. et al. Direct evidence of gradient Mn(II) evolution at charged states in LiNi0.5Mn1.5O4 electrodes with capacity fading. J. Power Sources 273, 1120–1126 (2015).

    Google Scholar 

  39. 39.

    Risch, M. et al. Redox processes of manganese oxide in catalyzing oxygen evolution and reduction: an in situ soft X-ray absorption spectroscopy study. J. Phys. Chem. C. 121, 17682–17692 (2017).

    Google Scholar 

  40. 40.

    Li, Q. H. et al. Quantitative probe of the transition metal redox in battery electrodes through soft X-ray absorption spectroscopy. J. Phys. D. 49, 413003 (2016).

    Google Scholar 

  41. 41.

    Venkatraman, S., Shin, Y. & Manthiram, A. Phase relationships and structural and chemical stabilities of charged Li1 − xCoO2 − δ and Li1 − xNi0.85Co0.15O2 − δ cathodes. Electrochem. Solid State Lett. 6, A9–A12 (2003).

    Google Scholar 

  42. 42.

    Hatsukade, T., Schiele, A., Hartmann, P., Brezesinski, T. & Janek, J. Origin of carbon dioxide evolved during cycling of nickel-rich layered NCM cathodes. ACS Appl. Mater. Interfaces 10, 38892–38899 (2018).

    Google Scholar 

  43. 43.

    Imhof, R. & Novak, P. Oxidative electrolyte solvent degradation in lithium-ion batteries: an in situ differential electrochemical mass spectrometry investigation. J. Electrochem. Soc. 146, 1702–1706 (1999).

    Google Scholar 

  44. 44.

    Jung, R., Metzger, M., Maglia, F., Stinner, C. & Gasteiger, H. A. Oxygen release and its effect on the cycling stability of LiNixMnyCozO2 (NMC) cathode materials for Li-ion batteries. J. Electrochem. Soc. 164, A1361–A1377 (2017).

    Google Scholar 

  45. 45.

    Wang, H. et al. CO2 and O2 evolution at high voltage cathode materials of Li-ion batteries: a differential electrochemical mass spectrometry study. Anal. Chem. 86, 6197–6201 (2014).

    Google Scholar 

  46. 46.

    de Biasi, L. et al. Chemical, structural, and electronic aspects of formation and degradation behavior on different length scales of Ni-rich NCM and Li-rich HE-NCM cathode materials in Li-ion batteries. Adv. Mater. 31, 1900985 (2019).

    Google Scholar 

Download references


We acknowledge the support from NSF ECCS-1610806 and Wuxi Weifu High-Technology Group Co., Ltd. This research used resources of the Center for Functional Nanomaterials and the 23-ID-2 (IOS) beamline of the National Synchrotron Light Source II, both of which are US Department of Energy Office of Science user facilities at Brookhaven National Laboratory, under contract DE-SC0012704. Also, this work was performed in part at the Center for Nanoscale Systems, a member of the National Nanotechnology Coordinated Infrastructure Network supported by the National Science Foundation under NSF award no. 1541959.

Author information




Z.Z. and J.Li conceived and designed the experiments. Z.Z. synthesized the materials and performed the electrochemical tests. D.Y, Y.Y. and B.W. performed the HRTEM imaging, STEM-EDS mapping, EELS line scan and focused ion beam sample preparation for aberration-corrected STEM characterizations. C.S. took aberration-corrected STEM images and performed the DFT calculations. D.Y., I.W. and A.H. measured the soft X-ray absorption. Z.Z., D.Y. and X.Y. did the sXAS data analysis. Z.Z. and J.Li wrote the paper. All authors analysed the data, discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Ju Li.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–14, Tables 1–3, Note 1, Discussion 1–4 and refs. 1–8.

Supplementary Video 1

M and O redox behaviours in the charging process.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Zhu, Z., Yu, D., Yang, Y. et al. Gradient Li-rich oxide cathode particles immunized against oxygen release by a molten salt treatment. Nat Energy 4, 1049–1058 (2019).

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