Extended perturbation formulae for Jahn–Teller molecules

Hill, Christian; Brown, John M.

doi:10.1016/j.jms.2004.09.002

Cited by 4 publications

(1 citation statement)

References 28 publications

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“…21 It can be inferred that in many doped layered oxides, the fundamental working principle behind correlated with the depression of PJTE by reduced vibronic couplings. 22,23 Based on this, we introduced a single cation (Mg), an anion (F), and both (Mg, F) to the bulk structure of LiCoO 2 . By studying the atomic environments of the dopants and the relationship between the crystal structures and the corresponding electrochemical performance, the doping effects based on modulation of PJTE were proposed.…”

Section: ■ Introductionmentioning

confidence: 99%

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

Ou,

Luo,

Zhang

et al. 2023

Chem. Mater.

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Doping could effectively tune the electrochemical performance of layered oxide cathodes in Li-ion batteries, whereas the working mechanism is usually oversimplified (i.e., a “pillar” effect). Although the Jahn–Teller effect is generally regarded as the fundamental origin of structural instability in some oxides, more polyhedral distortions are associated with pseudo-JTE (PJTE), which involves vibronic couplings. In this work, the atomic structures of doped LiCoO2 by Mg cations, F anions, and both were investigated thoroughly to reveal the atomic environments of these dopants and their influence on electrochemical performance. The function of these dopants as pillars is well discussed from the view of PJTE manipulation. Briefly, the MgO4 tetrahedra in Mg-doped LiCoO2 could suppress the charge transfer from the ligand to Co in neighboring octahedra, thus depressing PJTE. Although F doping does increase the ligand-field strength, the induced octahedral distortion reduces the structural stability dramatically. Comparatively, Mg/F co-doping generates the CoO5F–MgO4F2–CoO5F medium-range orders (MROs), which could depress both structural distortion and charge transfer in Co-centered octahedra for reduced PJTE. The reduced PJTE accounts for the improved electrochemical performance, making the co-doped LiCoO2 offer the best performance: a 70% capacity retention after 200 cycles within the potential range of 2.8–4.6 V, followed by Mg-doped LiCoO2. In contrast, although F-doping could induce an extra rock salt-like surface layer for higher capacity, its cycling improvement is rather limited. These results highlight the importance of structural modulation in enhancing the material performance and propose that the manipulation of PJTE would be an effective strategy in developing novel high-performance oxide cathodes.

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Section: ■ Introductionmentioning

confidence: 99%

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

Ou,

Luo,

Zhang

et al. 2023

Chem. Mater.

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The Jahn−Teller Effect in CH₃CN⁺ (X̃²E) and CD₃CN⁺ (X̃²E) Studied by Zero Kinetic Energy Photoelectron Spectroscopy

Yang

Zhou

2005

J. Phys. Chem. A

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The Jahn-Teller effect in CH(3)CN(+) (X(2)E) and CD(3)CN(+) (X(2)E) has been found experimentally by zero kinetic energy (ZEKE) photoelectron spectroscopy using coherent extreme ultraviolet (XUV) radiation. The vibronic bands of CH(3)CN(+) (X(2)E) and CD(3)CN(+) (X(2)E) at about 4500 cm(-1) above the ground states have been recorded. The spectra consist mainly of the Jahn-Teller active C-C[triple bond]N bending (v(8)), the CN stretching (v(2)), the CH(3) (CD(3)) deforming (v(6)), and the C-C stretching (v(4)) vibronic excitations. The Jahn-Teller active vibronic bands (v(8)) have been assigned with a harmonic model including linear and quadratic Jahn-Teller coupling terms, taking into account only the single mode vibronic excitation. The ionization potentials of CH(3)CN and CD(3)CN have also been determined, and their values are 12.2040(+/-0.001) and 12.2286(+/-0.001) eV, respectively.

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Different forms of effective Hamiltonians

Watson

2005

Molecular Physics

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Extended perturbation formulae for Jahn–Teller molecules

Cited by 4 publications

References 28 publications

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

The Jahn−Teller Effect in CH₃CN⁺ (X̃²E) and CD₃CN⁺ (X̃²E) Studied by Zero Kinetic Energy Photoelectron Spectroscopy

Different forms of effective Hamiltonians

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Extended perturbation formulae for Jahn–Teller molecules

Cited by 4 publications

References 28 publications

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

Reversible Li Intercalation in Layered Cathodes Enabled by Dopant-Induced Medium-Range Orders

The Jahn−Teller Effect in CH3CN+ (X̃2E) and CD3CN+ (X̃2E) Studied by Zero Kinetic Energy Photoelectron Spectroscopy

Different forms of effective Hamiltonians

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The Jahn−Teller Effect in CH₃CN⁺ (X̃²E) and CD₃CN⁺ (X̃²E) Studied by Zero Kinetic Energy Photoelectron Spectroscopy