Evolution of redox couples in Li- and Mn-rich cathode materials and mitigation of voltage fade by reducing oxygen release


Voltage fade is a major problem in battery applications for high-energy lithium- and manganese-rich (LMR) layered materials. As a result of the complexity of the LMR structure, the voltage fade mechanism is not well understood. Here we conduct both in situ and ex situ studies on a typical LMR material (Li1.2Ni0.15Co0.1Mn0.55O2) during charge–discharge cycling, using multi-length-scale X-ray spectroscopic and three-dimensional electron microscopic imaging techniques. Through probing from the surface to the bulk, and from individual to whole ensembles of particles, we show that the average valence state of each type of transition metal cation is continuously reduced, which is attributed to oxygen release from the LMR material. Such reductions activate the lower-voltage Mn3+/Mn4+ and Co2+/Co3+ redox couples in addition to the original redox couples including Ni2+/Ni3+, Ni3+/Ni4+ and O2−/O, directly leading to the voltage fade. We also show that the oxygen release causes microstructural defects such as the formation of large pores within particles, which also contributes to the voltage fade. Surface coating and modification methods are suggested to be effective in suppressing the voltage fade through reducing the oxygen release.

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Fig. 1: Electrochemical characterization of Li1.2Ni0.15Co0.1Mn0.55O2.
Fig. 2: XAS results of various elements in Li1.2Ni0.15Co0.1Mn0.55O2 at different cycles.
Fig. 3: Redox couple evolution of Li1.2Ni0.15Co0.1Mn0.55O2 during cycling.
Fig. 4: Surface degradation of Li1.2Ni0.15Co0.1Mn0.55O2 leading to larger overpotential.
Fig. 5: 3D electron tomography reconstruction of Li1.2Ni0.15Co0.1Mn0.55O2 materials.
Fig. 6: Spatially resolved EELS mapping of concealed and exposed pores.
Fig. 7: Thermal stability comparison between uncoated and AlF3-coated Li1.2Ni0.15Co0.1Mn0.55O2.


  1. 1.

    Lu, Z. & Dahn, J. R. Understanding the anomalous capacity of Li/Li[NixLi(1/3-2x/3)Mn(2/3-x/3)]O2 cells using in situ X-ray diffraction and electrochemical studies. J. Electrochem. Soc. 149, A815–A822 (2002).

    Article  Google Scholar 

  2. 2.

    Thackeray, M. M. et al. Li2MnO3-stabilized LiMO2 (M= Mn, Ni, Co) electrodes for lithium-ion batteries. J. Mater. Chem. 17, 3112–3125 (2007).

    Article  Google Scholar 

  3. 3.

    Sathiya, M. et al. Reversible anionic redox chemistry in high-capacity layered-oxide electrodes. Nat. Mater. 12, 827–835 (2013).

    Article  Google Scholar 

  4. 4.

    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).

    Article  Google Scholar 

  5. 5.

    Mizushima, K., Jones, P., Wiseman, P. & Goodenough, J. B. LixCoO2 (0<x≤1): A new cathode material for batteries of high energy density. Mater. Res. Bull. 15, 783–789 (1980).

    Article  Google Scholar 

  6. 6.

    Padhi, A. K., Nanjundaswamy, K. & Goodenough, J. Phospho-olivines as positive electrode materials for rechargeable lithium batteries. J. Electrochem. Soc. 144, 1188–1194 (1997).

    Article  Google Scholar 

  7. 7.

    Sathiya, M. et al. Origin of voltage decay in high-capacity layered oxide electrodes. Nat. Mater. 14, 230–238 (2015).

    Article  Google Scholar 

  8. 8.

    Dogan, F. et al. Re-entrant lithium local environments and defect driven electrochemistry of Li-and Mn-Rich Li-ion battery cathodes. J. Am. Chem. Soc. 137, 2328–2335 (2015).

    Article  Google Scholar 

  9. 9.

    Hu, E. Y. et al. Explore the effects of microstructural defects on voltage fade of Li- and Mn-rich cathodes. Nano Lett. 16, 5999–6007 (2016).

    Article  Google Scholar 

  10. 10.

    Xu, B., Fell, C. R., Chi, M. F. & Meng, Y. S. Identifying surface structural changes in layered Li-excess nickel manganese oxides in high voltage lithium ion batteries: A joint experimental and theoretical study. Energy Environ. Sci. 4, 2223–2233 (2011).

    Article  Google Scholar 

  11. 11.

    Gu, M. et al. Formation of the spinel phase in the layered composite cathode used in Li-ion batteries. ACS Nano 7, 760–767 (2013).

    Article  Google Scholar 

  12. 12.

    Hong, J. et al. Structural evolution of layered Li1.2Ni0.2Mn0.6O2 upon electrochemical cycling in a Li rechargeable battery. J. Mater. Chem. 20, 10179–10186 (2010).

    Article  Google Scholar 

  13. 13.

    Reed, J. & Ceder, G. Role of electronic structure in the susceptibility of metastable transition-metal oxide structures to transformation. Chem. Rev. 104, 4513–4533 (2004).

    Article  Google Scholar 

  14. 14.

    Li, H. Y., Xin, H. L., Muller, D. A. & Estroff, L. A. Visualizing the 3D internal structure of calcite single crystals grown in agarose hydrogels. Science 326, 1244–1247 (2009).

    Article  Google Scholar 

  15. 15.

    Ruckman, M. W. et al. Interpreting the near edges of O2 and O2 in alkali-metal superoxides. Phys. Rev. Lett. 67, 2533–2536 (1991).

    Article  Google Scholar 

  16. 16.

    Palina, N. et al. Electronic defect states at the LaAlO3/SrTiO3 heterointerface revealed by O K-edge X-ray absorption spectroscopy. Phys. Chem. Chem. Phys. 18, 13844–13851 (2016).

    Article  Google Scholar 

  17. 17.

    Goodenough, J. B. Evolution of strategies for modern rechargeable batteries. Acc. Chem. Res. 46, 1053–1061 (2013).

    Article  Google Scholar 

  18. 18.

    Lin, F. et al. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries. Nat. Commun. 5, 3529 (2014).

    Article  Google Scholar 

  19. 19.

    Yoon, W. S. et al. In situ soft XAS study on nickel-based layered cathode material at elevated temperatures: A novel approach to study thermal stability. Sci. Rep. 4, 6827 (2014).

    Article  Google Scholar 

  20. 20.

    Aurbach, D., Daroux, M., Faguy, P. & Yeager, E. The electrochemistry of noble metal electrodes in aprotic organic solvents containing lithium-salts. J. Electroanal. Chem. 297, 225–244 (1991).

    Article  Google Scholar 

  21. 21.

    Browning, J. F. et al. In situ determination of the liquid/solid interface thickness and composition for the Li ion cathode LiMn1.5Ni0.5O4. ACS Appl. Mater. Interface. 6, 18569–18576 (2014).

    Google Scholar 

  22. 22.

    Yamamoto, K. et al. Improved cyclic performance of lithium-ion batteries: an investigation of cathode/electrolyte interface via in situ total-reflection fluorescence X-ray absorption spectroscopy. J. Phys. Chem. C 118, 9538–9543 (2014).

    Article  Google Scholar 

  23. 23.

    Qiao, R. M. et al. Distinct solid-electrolyte-interphases on Sn (100) and (001) electrodes studied by soft X-ray spectroscopy. Adv. Mater. Interfaces 1, 1300115 (2014).

    Article  Google Scholar 

  24. 24.

    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).

    Article  Google Scholar 

  25. 25.

    Nithianandam, J., Rife, J. C. & Windischmann, H. Carbon-K edge spectroscopy of internal interface and defect states of chemical vapor-deposited diamond films. Appl. Phys. Lett. 60, 135–137 (1992).

    Article  Google Scholar 

  26. 26.

    Chiou, J. W. et al. Electronic structure of the carbon nanotube tips studied by X-ray-absorption spectroscopy and scanning photoelectron microscopy. Appl. Phys. Lett. 81, 4189–4191 (2002).

    Article  Google Scholar 

  27. 27.

    Gallant, B. M. et al. Chemical and morphological changes of Li-O2 battery electrodes upon cycling. J. Phys. Chem. C 116, 20800–20805 (2012).

    Article  Google Scholar 

  28. 28.

    Gauthier, M. et al. Electrode–electrolyte interface in Li-ion batteries: current understanding and new insights. J. Phys. Chem. Lett. 6, 4653–4672 (2015).

    Article  Google Scholar 

  29. 29.

    Seel, J. A. & Dahn, J. R. Electrochemical intercalation of PF6 into graphite. J. Electrochem. Soc. 147, 892–898 (2000).

    Article  Google Scholar 

  30. 30.

    Busche, M. R. et al. Dynamic formation of a solid–liquid electrolyte interphase and its consequences for hybrid-battery concepts. Nat. Chem. 8, 426–434 (2016).

    Article  Google Scholar 

  31. 31.

    Aurbach, D. Review of selected electrode-solution interactions which determine the performance of Li and Li ion batteries. J. Power Sources 89, 206–218 (2000).

    Article  Google Scholar 

  32. 32.

    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).

    Article  Google Scholar 

  33. 33.

    Yu, X. Q. et al. Understanding the rate capability of high-energy-density Li-rich layered Li1.2Ni0.15Co0.1Mn0.55O2 cathode materials. Adv. Energy Mater. 4, 1300950 (2014).

    Article  Google Scholar 

  34. 34.

    Rozier, P. & Tarascon, J. M. Review—Li-rich layered oxide cathodes for next-generation Li-ion batteries: chances and challenges. J. Electrochem. Soc. 162, A2490–A2499 (2015).

    Article  Google Scholar 

  35. 35.

    Lee, E. S. & Manthiram, A. Smart design of lithium-rich layered oxide cathode compositions with suppressed voltage decay. J. Mater. Chem. A 2, 3932–3939 (2014).

    Article  Google Scholar 

  36. 36.

    Saadoune, I. & Delmas, C. LiNi1−yCoyO2 positive electrode materials: relationships between the structure, physical properties and electrochemical behaviour. J. Mater. Chem. 6, 193–199 (1996).

    Article  Google Scholar 

  37. 37.

    Xu, Y. et al. Structural integrity—searching the key factor to suppress the voltage fade of Li-rich layered cathode materials through 3D X-ray imaging and spectroscopy techniques. Nano Energy 28, 164–171 (2016).

    Article  Google Scholar 

  38. 38.

    Xu, Y. et al. In situ visualization of state-of-charge heterogeneity within a LiCoO2 particle that evolves upon cycling at different rates. ACS Energy Lett. 2, 1240–1245 (2017).

    Article  Google Scholar 

  39. 39.

    Yan, P. F. et al. Intragranular cracking as a critical barrier for high-voltage usage of layer-structured cathode for lithium-ion batteries. Nat. Commun. 8, 14101 (2017).

    Article  Google Scholar 

  40. 40.

    Zheng, J. M. et al. Corrosion/fragmentation of layered composite cathode and related capacity/voltage fading during cycling process. Nano Lett. 13, 3824–3830 (2013).

    Article  Google Scholar 

  41. 41.

    Chen, C. J. et al. The origin of capacity fade in the Li2MnO3·LiMO2 (M=Li, Ni, Co, Mn) microsphere positive electrode: an operando neutron diffraction and transmission X-ray microscopy study. J. Am. Chem. Soc. 138, 8824–8833 (2016).

    Article  Google Scholar 

  42. 42.

    Kim, H., Kim, M. G., Jeong, H. Y., Nam, H., & Cho, J. A new coating method for alleviating surface degradation of LiNi0.6Co0.2Mn0.2O2 cathode material: nanoscale surface treatment of primary particles. Nano Lett. 15, 2111–2119 (2015).

    Article  Google Scholar 

  43. 43.

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

    Article  Google Scholar 

  44. 44.

    Nayak, P. K. et al. Al doping for mitigating the capacity fading and voltage decay of layered Li and Mn-rich cathodes for Li-ion batteries. Adv. Energy Mater. 6, 1502398 (2016).

    Article  Google Scholar 

  45. 45.

    Hu, E. Y. et al. Utilizing environmental friendly iron as a substitution element in spinel structured cathode materials for safer high energy lithium-ion batteries. Adv. Energy Mater. 6, 1501662 (2016).

    Article  Google Scholar 

  46. 46.

    Nam, K. W. et al. Combining in situ synchrotron X-ray diffraction and absorption techniques with transmission electron microscopy to study the origin of thermal instability in overcharged cathode materials for lithium-ion batteries. Adv. Funct. Mater. 23, 1047–1063 (2013).

    Article  Google Scholar 

  47. 47.

    Hu, E. Y. et al. Oxygen-release-related thermal stability and decomposition pathways of LixNi0.5Mn1.5O4 cathode materials. Chem. Mater. 26, 1108–1118 (2014).

    Article  Google Scholar 

  48. 48.

    Schilling, O. & Dahn, J. R. Thermodynamic stability of chemically delithiated Li(LixMn2-x)O4. J. Electrochem. Soc. 145, 569–575 (1998).

    Article  Google Scholar 

  49. 49.

    Wang, L., Maxisch, T. & Ceder, G. A first-principles approach to studying the thermal stability of oxide cathode materials. Chem. Mater. 19, 543–552 (2007).

    Article  Google Scholar 

  50. 50.

    Bak, S. M. et al. Structural changes and thermal stability of charged LiNixMnyCozO2 cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy. ACS appl. Mater. Interfaces. 2014, 22594–22601 (2014).

    Article  Google Scholar 

  51. 51.

    Kim, J. H. et al. Effect of aluminum fluoride coating on the electrochemical and thermal properties of 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 composite material. J. Alloys Compd. 517, 20–25 (2012).

    Article  Google Scholar 

  52. 52.

    Kim, H. B. et al. Electrochemical and thermal characterization of AlF3-coated Li[Ni0.8Co0.15Al0.05]O2 cathode in lithium-ion cells. J. Power Sources 179, 347–350 (2008).

    Article  Google Scholar 

  53. 53.

    Zheng, J. M. et al. Functioning mechanism of AlF3 coating on the Li- and Mn-rich cathode materials. Chem. Mater. 26, 6320–6327 (2014).

    Article  Google Scholar 

  54. 54.

    Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12, 537–541 (2005).

    Article  Google Scholar 

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We acknowledge the technical support of the beamline scientists J. Bai of X14A, NSLS and S. N. Ehrlich of X18A, NSLS. The work carried out Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the US Department of Energy through the Advanced Battery Materials Research (BMR) Program, including the Battery500 Consortium under contract DE-SC0012704. Use of STEM at the Center for Functional Nanomaterials of Brookhaven National Laboratory was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-SC0012704. The work at the Institute of Physics was supported by funding from the ‘One Hundred Talent Project’ of the Chinese Academy of Sciences, the National Key R&D Program of China (grant no. 2016YFA0202500) and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (grant no. 51421002). The work carried out at Dongguk University was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science & ICT (NRF-2017M1A2A2044502). Certain commercial names are mentioned for purposes of illustration and do not constitute an endorsement by the National Institute of Standards and Technology. J.L. and K.A. gratefully acknowledge support from the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office. Argonne National Laboratory is operated for DOE Office of Science by UChicago Argonne, LLC, under contract no. DE-AC02-06CH11357. This research used beamlines X14A, X18A and U7A of the National Synchrotron Light Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-AC02-98CH10886.

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X.Y. and X.-Q.Y. designed the work; X.Y. and J.L. performed the electrochemical measurements; X.Y. and K.-W.N. performed the hard X-ray in situ XAS experiments; X.Y., S.B., K.-W.N., C.J. and D.A.F. performed the soft XAS experiments; E.H. and X.Y. performed the XAS analysis; S.B. and K.-W.N. performed the thermal experiments. R.L. and H.L.X. performed the STEM experiments and wrote the discussion part related to the STEM experiment. X.B. and J.L. performed the DEMS measurements. E.H. wrote the manuscript with critical input from all other authors; X.-Q.Y., X.Y., H.L.X. and J.L. edited and finalized the manuscript.

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Correspondence to Xiqian Yu or Jun Lu or Huolin L. Xin.

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Hu, E., Yu, X., Lin, R. 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). https://doi.org/10.1038/s41560-018-0207-z

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