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Title: Correlations between Transition Metal Chemistry, Local Structure and Global Structure in Li 2Ru 0.5Mn 0.5O 3 Investigated in a Wide Voltage Window

Li 2Ru 0.5Mn 0.5O 3, a high capacity lithium rich layered cathode material for lithium-ion batteries, was subject to comprehen-sive diagnostic studies including in situ/ex situ X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), pair distribu-tion function (PDF) and high resolution scanning transmission electron microscopy (STEM) analysis, to understand the cor-relations between transition metal chemistry, structure and lithium storage electrochemical behavior. Ru-Ru dimers have been identified in the as-prepared sample and found to be preserved upon prolonged cycling. Presence of these dimers, which are likely caused by the delocalized nature of 4d electrons, is found to favor the stabilization of the structure in a lay-ered phase. The in situ XAS results confirm the participation of oxygen redox into the charge compensation at high charge voltage, and the great flexibility of the covalent bond between Ru and O may provide great reversibility of the global struc-ture despite of the significant local distortion around Ru. In contrast, the local distortion around Mn occurs at low discharge voltage and is accompanied by a “layered to 1T” phase transformation, which is found to be detrimental to the cycle per-formances. It is clear that the changes of local structure around individual transition metal cations respond separatelymore » and differently to lithium intercalation/deintercalation. Here, cations with the capability to tolerate the lattice distortion will benefit for maintaining the integrality of the crystal structure and therefore is able to enhance the long-term cycling performance of the electrode materials.« less
ORCiD logo [1] ;  [2] ;  [3] ;  [3] ; ORCiD logo [3] ;  [4] ;  [2] ; ORCiD logo [4] ; ORCiD logo [5] ;  [2] ; ORCiD logo [3]
  1. Chinese Academy of Sciences (CAS), Beijing (China); Shanghai Univ., Shanghai (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Chinese Academy of Sciences (CAS), Beijing (China)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
Publication Date:
Report Number(s):
Journal ID: ISSN 0897-4756; R&D Project: MA453MAEA; VT1201000; TRN: US1702902
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 21; Journal ID: ISSN 0897-4756
American Chemical Society (ACS)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
25 ENERGY STORAGE; National Synchrotron Light Source; lithium-ion batteries; cathode; lithium rich layered oxides
OSTI Identifier: