Abstract
P2-type Na2/3Ni1/3Mn2/3O2 (PNNMO) has been extensively studied because of its desirable electrochemical properties as a positive electrode for sodium-ion batteries. PNNMO exhibits intralayer transition-metal ordering of Ni and Mn and intralayer Na+/vacancy ordering. The Na+/vacancy ordering is often considered a major impediment to fast Na+ transport and can be affected by transition-metal ordering. We show by neutron/X-ray diffraction and density functional theory (DFT) calculations that Li doping (Na2/3Li0.05Ni1/3Mn2/3O2, LFN5) promotes ABC-type interplanar Ni/Mn ordering without disrupting the Na+/vacancy ordering and creates low-energy Li-Mn-coordinated diffusion pathways. A structure model is developed to quantitatively identify both the intralayer cation mixing and interlayer cationic stacking fault densities. Quasielastic neutron scattering reveals that the Na+ diffusivity in LFN5 is enhanced by an order of magnitude over PNNMO, increasing its capacity at a high current. Na2/3Ni1/4Mn3/4O2 (NM13) lacks Na+/vacancy ordering but has diffusivity comparable to that of LFN5. However, NM13 has the smallest capacity at a high current. The high site energy of Mn-Mn-coordinated Na compared to that of Ni-Mn and higher density of Mn-Mn-coordinated Na+ sites in NM13 disrupts the connectivity of low-energy Ni-Mn-coordinated diffusion pathways. These results suggest that the interlayer ordering can be tuned through the control of composition, which has an equal or greater impact on Na+ diffusion than the Na+/vacancy ordering.
| Original language | English |
|---|---|
| Pages (from-to) | 15108-15118 |
| Number of pages | 11 |
| Journal | Journal of the American Chemical Society |
| Volume | 146 |
| Issue number | 22 |
| DOIs | |
| State | Published - Jun 5 2024 |
Funding
This material was based upon work supported by the Department of the Navy, Office of Naval Research under Award Number N00014-23-1-2343. E.G. also thanks the U.S. Department of Energy, the Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) (DE-SC0014664). Z.W., V.V.S., and S.P.O. acknowledge support from the National Science Foundation (NSF) FMRG project (Grant Number 2017027-4). K.G. acknowledges the support of the U.S. NSF (Grant Number DUE- 2111549). C. K. acknowledges the support of the NASA Idaho Space Grant Consortium (ISGC) fellowship. D.H. thanks the support by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences program under Award Number DE-SC0024404. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research used resources from the Advanced Photon Source and Center for Nanoscale Materials, a DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. This research used beamline 28-ID-2 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. Work at ORNL\u2019s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for U.S. DOE under Contract No. DEAC05-00OR22725. QClimax is a part of the Integrated Computational Environment Modeling and Analysis of Neutron Data (ICE-MAN) (LDRD 8237) project, funded by the Laboratory Directed Research and Development program at ORNL. The computational portions of this work used Expanse at the San Diego Supercomputer Center through allocation DMR150014 from the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) program, which is supported by National Science Foundation grants #2138259, #2138286, #2138307, #2137603, and #2138296. Funding for the analytical infrastructure of the Boise State Isotope Geology Laboratory used in this study was provided by NSF Grants EAR-1735889 and EAR-1920336.