Structural  evolution of layered LixMnyO2: Combined neutron, NMR, and electrochemical study

A R Armstrong; A J Paterson; N Dupre; C P Gray; Peter George Bruce

doi:10.1021/cm0621747

Structural evolution of layered LixMnyO₂: Combined neutron, NMR, and electrochemical study

A R Armstrong, A J Paterson, N Dupre, C P Gray, Peter George Bruce

Research output: Contribution to journal › Article › peer-review

Abstract

The conversion upon electrochemical cycling from a layered structure to a spinel in nonstoichiometric LixMnyO2 has been studied by neutron diffraction and NMR. This process occurs in all layered lithium manganate materials, irrespective of the ion-exchange route. The high temperature of the ion exchange under reflux in n-hexanol is sufficient to promote formation of some spinel within the as-synthesized material. Upon cycling, all the different layered LixMnyO2 compounds begin to transform to a spinel. In the first 50 or so cycles, the various layered LixMnyO2 compounds behave rather differently, with a higher spinel fraction being observed for materials ion-exchanged under more extreme conditions. However, the rate of this transformation is significantly slower than was observed in stoichiometric layered LiMnO2, with only 25% spinel observed after 100 cycles. Ultimately, upon extended cycling, the entire structure will form a well-ordered spinel phase.

Original language	English
Pages (from-to)	1016-1023
Number of pages	8
Journal	Chemistry of Materials
Volume	19
Issue number	5
DOIs	https://doi.org/10.1021/cm0621747
Publication status	Published - 6 Mar 2007

Keywords

RECHARGEABLE LITHIUM BATTERIES
INTERCALATION COMPOUNDS
POSITIVE ELECTRODE
CATHODE MATERIALS
ION-EXCHANGE
LIMNO2
DIFFRACTION
PERFORMANCE
LI-6

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@article{3773250b18504fadbf8566642efc7777,

title = "Structural evolution of layered LixMnyO2: Combined neutron, NMR, and electrochemical study",

abstract = "The conversion upon electrochemical cycling from a layered structure to a spinel in nonstoichiometric LixMnyO2 has been studied by neutron diffraction and NMR. This process occurs in all layered lithium manganate materials, irrespective of the ion-exchange route. The high temperature of the ion exchange under reflux in n-hexanol is sufficient to promote formation of some spinel within the as-synthesized material. Upon cycling, all the different layered LixMnyO2 compounds begin to transform to a spinel. In the first 50 or so cycles, the various layered LixMnyO2 compounds behave rather differently, with a higher spinel fraction being observed for materials ion-exchanged under more extreme conditions. However, the rate of this transformation is significantly slower than was observed in stoichiometric layered LiMnO2, with only 25% spinel observed after 100 cycles. Ultimately, upon extended cycling, the entire structure will form a well-ordered spinel phase.",

keywords = "RECHARGEABLE LITHIUM BATTERIES, INTERCALATION COMPOUNDS, POSITIVE ELECTRODE, CATHODE MATERIALS, ION-EXCHANGE, LIMNO2, DIFFRACTION, PERFORMANCE, LI-6",

author = "Armstrong, {A R} and Paterson, {A J} and N Dupre and Gray, {C P} and Bruce, {Peter George}",

year = "2007",

month = mar,

day = "6",

doi = "10.1021/cm0621747",

language = "English",

volume = "19",

pages = "1016--1023",

journal = "Chemistry of Materials",

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TY - JOUR

T1 - Structural evolution of layered LixMnyO2: Combined neutron, NMR, and electrochemical study

AU - Armstrong, A R

AU - Paterson, A J

AU - Dupre, N

AU - Gray, C P

AU - Bruce, Peter George

PY - 2007/3/6

Y1 - 2007/3/6

N2 - The conversion upon electrochemical cycling from a layered structure to a spinel in nonstoichiometric LixMnyO2 has been studied by neutron diffraction and NMR. This process occurs in all layered lithium manganate materials, irrespective of the ion-exchange route. The high temperature of the ion exchange under reflux in n-hexanol is sufficient to promote formation of some spinel within the as-synthesized material. Upon cycling, all the different layered LixMnyO2 compounds begin to transform to a spinel. In the first 50 or so cycles, the various layered LixMnyO2 compounds behave rather differently, with a higher spinel fraction being observed for materials ion-exchanged under more extreme conditions. However, the rate of this transformation is significantly slower than was observed in stoichiometric layered LiMnO2, with only 25% spinel observed after 100 cycles. Ultimately, upon extended cycling, the entire structure will form a well-ordered spinel phase.

AB - The conversion upon electrochemical cycling from a layered structure to a spinel in nonstoichiometric LixMnyO2 has been studied by neutron diffraction and NMR. This process occurs in all layered lithium manganate materials, irrespective of the ion-exchange route. The high temperature of the ion exchange under reflux in n-hexanol is sufficient to promote formation of some spinel within the as-synthesized material. Upon cycling, all the different layered LixMnyO2 compounds begin to transform to a spinel. In the first 50 or so cycles, the various layered LixMnyO2 compounds behave rather differently, with a higher spinel fraction being observed for materials ion-exchanged under more extreme conditions. However, the rate of this transformation is significantly slower than was observed in stoichiometric layered LiMnO2, with only 25% spinel observed after 100 cycles. Ultimately, upon extended cycling, the entire structure will form a well-ordered spinel phase.

KW - RECHARGEABLE LITHIUM BATTERIES

KW - INTERCALATION COMPOUNDS

KW - POSITIVE ELECTRODE

KW - CATHODE MATERIALS

KW - ION-EXCHANGE

KW - LIMNO2

KW - DIFFRACTION

KW - PERFORMANCE

KW - LI-6

UR - http://www.scopus.com/inward/record.url?scp=33947193539&partnerID=8YFLogxK

U2 - 10.1021/cm0621747

DO - 10.1021/cm0621747

M3 - Article

SN - 0897-4756

VL - 19

SP - 1016

EP - 1023

JO - Chemistry of Materials

JF - Chemistry of Materials

IS - 5

ER -

Structural evolution of layered LixMnyO₂: Combined neutron, NMR, and electrochemical study

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Keywords

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