Nonstoichiometry and defect structure of spinel LiMn2O4 − δ

Sugiyama, Jun; Atsumi, Taroh; Hioki, Tatsumi; Noda, Shoji; Kamegashira, Naoki

doi:10.1016/s0378-7753(96)02595-5

Cited by 42 publications

(23 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8,9,14 The structure of Mn 3 O 4 can be obtained by repeated substitution of Li by Mn at the 8a positions of LiMn 2 O 4 if we neglect a distortion of the Mn 3 O 4 structure due to the cooperative Jahn-Teller distortion of Mn 3ϩ ions. This suggests that the defect structure shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

First Principles Calculations of Formation Energies and Electronic Structures of Defects in Oxygen-Deficient LiMn[sub 2]O[sub 4]

Koyama

Tanaka

Adachi

et al. 2003

J. Electrochem. Soc.

View full text Add to dashboard Cite

The formation energies of many kinds of defects for oxygen-deficient LiMn 2 O 4 , including both oxygen-vacancy types and metalinterstitial types, have been determined by first principles plane-wave pseudopotential calculations. Two kinds of metal-excess defects show the lowest formation energies. They were found to be more stable than the simple oxygen vacancy that exhibits the lowest formation energy among oxygen-vacancy-type defects. In both of the metal-excess defects with the lowest formation energies, excess Li occupies an empty 16c position of spinel. Excess Mn is present either at the 8a position, substituting for Li, or at the empty 16c position, moving one neighboring Li into the next 16c position. The results are consistent with experimental results of density measurements, diffusion experiments, and decomposition reactions at high temperatures. Detailed examination of the electronic structures revealed that formal charges of both interstitial and substituted Mn are ϩ2.

show abstract

Section: Discussionmentioning

confidence: 99%

First Principles Calculations of Formation Energies and Electronic Structures of Defects in Oxygen-Deficient LiMn[sub 2]O[sub 4]

Koyama

Tanaka

Adachi

et al. 2003

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…The effects of oxygen non-stoichiometry in the traditional LiMn 2 O 4 spinel have been well studied before [38][39][40][41][42]. In case of LiMn 2 O 4 , oxygen deficiency is considered as a trigger of structural degradation and capacity fading due to the dominating Mn 3+ and its damaging Jahn- [45].…”

Section: Oxygen Non-stoichiometry In Spinel Cathodesmentioning

confidence: 99%

The roles of oxygen non-stoichiometry on the electrochemical properties of oxide-based cathode materials

2016

View full text Add to dashboard Cite

Cathode materials with both high energy density and high power capability are in great demand to improve the performance of lithium ion batteries and expand the driving range of electric vehicles. Of particular interest are transition metal oxide-based cathodes. However, electrochemical performance of these cathode materials is very sensitive to the synthetic conditions and, particularly, the oxygen non-stoichiometry that is induced during high temperature synthesis and post-treatment. This review highlights the critical roles of oxygen nonstoichiometry in high-energy-density cathode materials including high voltage spinel LiNi 0.5 Mn 1.5 O 4 , Ni-rich layered LiNi x Mn y Co z O 2 (NMC, x > 0.5), and the Li-rich, Mn-rich layered cathode, with the aim to provide a fundamental understanding on the effects of the (J.-G. Zhang).Abbreviations: ALMO annealed Li 2 MnO 3 EELS electron energy loss spectroscopy EV electric vehicle LIB lithium ion battery LMR Li-rich Mn-rich MLMO quenched Li 2 MnO 3 milled with Super P NMC LiNi x Mn y Co z O 2 QLMO quenched Li 2 MnO 3 TG thermogravimetric TM transition metal © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/oxygen non-stoichiometry governing the crystalline structure, electrochemical performance, and thermal stability of different cathode materials. This review also offers perspectives and directions on how to best utilize oxygen non-stoichiometry in the future development of highenergy-density cathode materials for lithium ion batteries. KeywordsOxygen non-stoichiometry; Cathode materials; Ni-rich material; High voltage spinel; Li-rich Mn-rich; Lithium ion battery. Highlights Oxygen non-stoichiometry, which is sensitive to the synthesis conditions, plays a critical role in manipulating the material crystal structure. Oxygen non-stoichiometry fundamentally affects the reaction pathway, electrochemical performances and thermal stability of cathode materials. The effects of oxygen non-stoichiometry should be carefully considered in the future development of high-energy-density cathode materials for lithium-ion batteries.

show abstract

“…The oxygen vacancy was indicated first by the thermogravimetry measurements. 3,12,13) Two structure models were proposed for the ''oxygen vacancy'' phase: vacancy at the oxygen site corresponding to the formula LiMn 2 O 4À , and excess cations at the interstitial site with the formula, Li 1þx Mn 2þy O 4 . These models were, in fact, claimed by experimental results; the oxygen deficient spinel LiMn 2 O 4À with vacancy clustering based on the NMR data, 13) oxygen vacancy indicated by chemical analysis, 14) and interstitial cations at the 16c octahedral site in Fd 3 3m space group determined by density measurement.…”

Section: )mentioning

confidence: 99%

Phase Transitions and Low-temperature Structure of Lithium Manganese Oxide Spinel

et al. 2004

View full text Add to dashboard Cite

Low-temperature structures of the lithium manganese spinels were determined using TOF neutron Rietveld analysis. The spinels LiMn 2 O 4À with different values, (0.016, 0.040, and 0.132) showed the cubic-orthorhombic phase transitions, and the lattice distortion decreased with decreasing . Although no anomaly corresponding to the cubic-orthorhombic phase transition was observed in the DSC curve for the spinel with $ 0:016, the transition was observed by the structure analysis, which is consistent with the broad Cp anomaly at 250 K. The cubic-orthorhombic phase transition is closely correlated to the existence of the vacancy. The charge disproportionation into trivalent and tetravalent state proceeds gradually with decreasing temperature, and the extent of the disproportionation is dependent on the vacancy. Based on the structure analysis, the phase transitions in the spinel are discussed.

show abstract

Nonstoichiometry and defect structure of spinel LiMn2O4 − δ

Cited by 42 publications

References 8 publications

First Principles Calculations of Formation Energies and Electronic Structures of Defects in Oxygen-Deficient LiMn[sub 2]O[sub 4]

First Principles Calculations of Formation Energies and Electronic Structures of Defects in Oxygen-Deficient LiMn[sub 2]O[sub 4]

The roles of oxygen non-stoichiometry on the electrochemical properties of oxide-based cathode materials

Phase Transitions and Low-temperature Structure of Lithium Manganese Oxide Spinel

Contact Info

Product

Resources

About