Abstract
Oxygen activity in highly delithiated LiCoO2 is critical to fully utilizing the energy density of this high-tap-density cathode but still lacks a clear understanding. In this work, we combined the results of several experimental techniques, especially resonant inelastic X-ray scattering (RIXS) and neutron pair distribution function (NPDF) analysis, together with theoretical calculations to study this topic. Our results conclude that oxygen redox takes place globally in the lattice, rather than forming localized dimerization as previously thought. RIXS results directly reveal the reversible oxygen redox, and NPDF results show that the O–O pair distance is considerably shortened in the highly delithiated LiCoO2. Theoretical calculations indicate that no O–O bonding is formed in LiCoO2, in sharp contrast to the lithium-rich system in which O–O bonding does form. These results provide the rationale for achieving a reversible deep delithiation and high energy density for LiCoO2-based electrodes.
| Original language | English |
|---|---|
| Pages (from-to) | 720-736 |
| Number of pages | 17 |
| Journal | Joule |
| Volume | 5 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 17 2021 |
Funding
The authors thank Professor John. B. Goodenough for the insightful discussions. The work done at Institute of Physics, Chinese Academy of Sciences was supported by funding from National Key R&D Program of China (grant no. 2016YFB0100100). The work done at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704. Neutron powder diffraction measurements used resources at the Spallation Neutron Source (POWGEN and NOMAD beamlines), a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. J.L. and K.P are partially supported by U.S. DOE, Office of Science, Office of Basic Energy Sciences, Early Career Research Program award KC040602, under contract number DE-AC05-00OR22725. This research used beamline 7-BM and 28-ID-2 of the National Synchrotron Light Source II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. This research used beamline 17BM of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. Technique supports from beamline BL14W1 at Shanghai Synchrotron Radiation Facility (SSRF, China) are acknowledged. The authors acknowledge Prof. Wen Liu from Beijing University of Chemical Technology for the help of EPR measurement. Soft X-ray characterization was carried out at the Advanced Light Source (ALS). ALS is a U.S. DOE, Office of Science User Facility under contract no. DE-AC02-05CH11231. E.H. X.Y. W.Y. and X.-Q.Y. conceived the idea. E.H. J.L. X.Y. and K.P. performed neutron total scattering experiment and data analysis; E.H. and X.Y. performed XAS measurements and analysis; Q.L. and W.Y. performed the RIXS experiment and carried out the data analysis. E.H. J.L. and W.X. performed the neutron and XRD measurements and data analysis; X.W. R.X. and H.L. performed DFT analysis. All the authors participated in the discussions of the results as well as the preparation of the manuscript. The authors declare no competing interests. The authors thank Professor John. B. Goodenough for the insightful discussions. The work done at Institute of Physics, Chinese Academy of Sciences was supported by funding from National Key R&D Program of China (grant no. 2016YFB0100100 ). The work done at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704 . Neutron powder diffraction measurements used resources at the Spallation Neutron Source (POWGEN and NOMAD beamlines), a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory . J.L. and K.P are partially supported by U.S. DOE , Office of Science, Office of Basic Energy Sciences, Early Career Research Program award KC040602, under contract number DE-AC05-00OR22725 . This research used beamline 7-BM and 28-ID-2 of the National Synchrotron Light Source II , a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. This research used beamline 17BM of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. Technique supports from beamline BL14W1 at Shanghai Synchrotron Radiation Facility (SSRF, China) are acknowledged. The authors acknowledge Prof. Wen Liu from Beijing University of Chemical Technology for the help of EPR measurement. Soft X-ray characterization was carried out at the Advanced Light Source (ALS). ALS is a U.S. DOE, Office of Science User Facility under contract no. DE-AC02-05CH11231.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-SC0012704 |
| Office of Science | |
| Office of Energy Efficiency and Renewable Energy | |
| Basic Energy Sciences | DE-AC05-00OR22725, KC040602, 28-ID-2 |
| Argonne National Laboratory | DE-AC02-05CH11231, DE-AC02-06CH11357 |
| Oak Ridge National Laboratory | |
| Brookhaven National Laboratory | |
| Beijing University of Chemical Technology | |
| National Key Research and Development Program of China | 2016YFB0100100 |
Keywords
- DFT
- RIXS
- XAS
- high-voltage LiCoO
- neutron PDF
- oxygen-redox reaction
