Unveiling the role of Mn-interstitial defect and particle size on the Jahn-Teller distortion of the LiMn2O4 cathode material

Renier Arabolla Rodríguez, Nelcy Della Santina Mohallem, Manuel Avila Santos, Demetrio A. Sena Costa, Luciano Andrey Montoro, Yodalgis Mosqueda Laffita, Luis A. Tavera Carrasco, Eduardo L. Perez-Cappe

Research output: Contribution to journalArticlepeer-review

Abstract

This work proposes to unveil the underlying effect of Mn-interstitial defect as well as the particle size on the Jahn Teller distortion. Mn-interstitial defects and nanometric particles were characterized by HRTEM, Rietveld fitting and microstrain XRD analysis. The research was conducted by measuring the changes of the Fermi level, entropy, enthalpy and the redox potential due to the JT transition. Other dynamic electrochemical measurements were also carried out. The structural and microstructural measurements led to propose the presence of Mn ions in distorted tetrahedral 48f positions after using irradiation to induce Mn-interstitial defects. By using the proposed methodology it was possible to experimentally observe that this defect vanishes the JT effect and diminishes the shifting of the Fermi level during the phase transition. Subtle correlations between the capacity of the 3V region and the redox potential drop of these materials were revealed and explained. The surface pressure and bonding effects were set as important factors underlying stunning electrochemical and structural changes that characterise nanometric particles below 15 nm.

Original languageEnglish
Article number229519
JournalJournal of Power Sources
Volume490
DOIs
StatePublished - 1 Apr 2021

Keywords

  • Defects
  • Fermi level
  • Jahn-Teller effect
  • LiMnO
  • Nano-size effect
  • Surface pressure

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