Abstract
Electrochemical (de)intercalation is a delicate method to precisely control the alkaline ion composition in alkaline transition metal oxides. Because of complicated interactions, metal charge ordering patterns can form spontaneously at special fractional alkaline compositions and orderings. Here, we show that this elegant electrochemical process can create dynamically preferred structures in an anharmonic energy landscape that conventional syntheses and computations can rarely visit. Specifically, electrochemically prepared Na1/2MnO2 ordering exhibits abnormal structure distortions, charge orderings, and dynamical activities. Strong magnetic fluctuations and lattice dynamics are observed in an unusually wide temperature range in Na1/2MnO2, which distinguishes it from all other NaxMnO2 at higher or lower Na compositions. The results emphasize the unique opportunity of using electrochemical processes to design and create novel quantum states with strongly coupled and mutually enhanced electronic and lattice fluctuations, likely through a special dynamic charge flux functional, as suggested by our computational investigations.
Original language | English |
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Pages (from-to) | 735-750 |
Number of pages | 16 |
Journal | Matter |
Volume | 5 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2 2022 |
Funding
This work was supported by the Dean's competitive fund of promising scholarship at FAS at Harvard University and a Harvard Data Science Initiative Competitive Research Award. Y.W. and K.B. acknowledge primary support from the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under award DE-SC0018675. Computations were supported by computational resources from the Texas Advanced Computing Center (TACC) and the Odyssey cluster supported by the FAS Division of Science, Research Computing Group at Harvard University. This work also made use of the Shared Experimental Facilities supported in part by the Materials Research Science and Engineering Centers (MRSEC) Program of the National Science Foundation under award DMR-1419807. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the DOE, Office of Science, Office of Basic Energy Sciences, under contract DE-AC02-06CH11357. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. The work done at BNL is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the DOE through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704. This research used beamline 28-ID-2 of the NSLS II, a DOE Office of Science user facility operated for the DOE Office of Science by BNL under contract DE-SC0012704. The neutron diffraction studies at NOMAD used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by ORNL. X.L. conceived the project and planned the research. X.C. performed the DFT calculations. Yichao Wang synthesized NaMnO2, NaCoO2, and NaNiO2 powder samples for in situ SXRD and prepared the chemically desodiated Na1/2MnO2 for neutron and Raman measurements. Yiping Wang and K.B performed Raman setup and measurements, and Yichao Wang and X.C. assisted with remote monitoring during the measurements. R.L.D. and J.W.L. performed the temperature-dependent neutron diffraction and inelastic neutron scattering measurements, analyzed inelastic neutron scattering data, and performed the magnetic structure refinement. X.L. and K.W performed the in situ synchrotron XRD measurements. T.Q. obtained the phonon modes, DOS, and temperature-dependent oscillation amplitudes from DFT calculations. J.L. performed the neutron diffraction and neutron PDF measurements at room temperature and the structural refinements. E.H. performed the ex situ synchrotron XRD measurements. X.C. and X.L. analyzed the experimental data with the help of discussions with all authors. X.C. and X.L. analyzed the computational and experimental results and wrote the manuscript. X.L. conceived the physical picture of entangled magnetic and lattice dynamics through charge flux functionals. The authors declare no competing interests. This work was supported by the Dean’s competitive fund of promising scholarship at FAS at Harvard University and a Harvard Data Science Initiative Competitive Research Award. Y.W. and K.B. acknowledge primary support from the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under award DE-SC0018675 . Computations were supported by computational resources from the Texas Advanced Computing Center ( TACC ) and the Odyssey cluster supported by the FAS Division of Science, Research Computing Group at Harvard University . This work also made use of the Shared Experimental Facilities supported in part by the Materials Research Science and Engineering Centers ( MRSEC ) Program of the National Science Foundation under award DMR-1419807 . Use of the Advanced Photon Source at Argonne National Laboratory was supported by the DOE, Office of Science, Office of Basic Energy Sciences, under contract DE-AC02-06CH11357 . The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. The work done at BNL is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the DOE through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704 . This research used beamline 28-ID-2 of the NSLS II, a DOE Office of Science user facility operated for the DOE Office of Science by BNL under contract DE-SC0012704 . The neutron diffraction studies at NOMAD used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by ORNL.
Keywords
- MAP3: Understandings
- NaMnO
- anharmonic phonon coupling
- charge flux fluctuations
- charge flux functional
- charge ordering
- lattice and electron dynamics
- magnetic ordering
- sodium manganates
- sodium ordering
- strong magnetic fluctuations