Dataset Information

Identifying the Structure of the Intermediate, Li2/3CoPO4, Formed during Electrochemical Cycling of LiCoPO4.

ABSTRACT: In situ synchrotron diffraction measurements and subsequent Rietveld refinements are used to show that the high energy density cathode material LiCoPO4 (space group Pnma) undergoes two distinct two-phase reactions upon charge and discharge, both occurring via an intermediate Li2/3(Co(2+))2/3(Co(3+))1/3PO4 phase. Two resonances are observed for Li2/3CoPO4 with intensity ratios of 2:1 and 1:1 in the (31)P and (7)Li NMR spectra, respectively. An ordering of Co(2+)/Co(3+) oxidation states is proposed within a (a × 3b × c) supercell, and Li(+)/vacancy ordering is investigated using experimental NMR data in combination with first-principles solid-state DFT calculations. In the lowest energy configuration, both the Co(3+) ions and Li vacancies are found to order along the b-axis. Two other low energy Li(+)/vacancy ordering schemes are found only 5 meV per formula unit higher in energy. All three configurations lie below the LiCoPO4-CoPO4 convex hull and they may be readily interconverted by Li(+) hops along the b-direction.

SUBMITTER: Strobridge FC

PROVIDER: S-EPMC4419286 | biostudies-other | 2014 Nov

REPOSITORIES: biostudies-other

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Identifying the Structure of the Intermediate, Li2/3CoPO4, Formed during Electrochemical Cycling of LiCoPO4.

Strobridge Fiona C FC Clément Raphaële J RJ Leskes Michal M Middlemiss Derek S DS Borkiewicz Olaf J OJ Wiaderek Kamila M KM Chapman Karena W KW Chupas Peter J PJ Grey Clare P CP

Chemistry of materials : a publication of the American Chemical Society 20141009 21

In situ synchrotron diffraction measurements and subsequent Rietveld refinements are used to show that the high energy density cathode material LiCoPO4 (space group Pnma) undergoes two distinct two-phase reactions upon charge and discharge, both occurring via an intermediate Li2/3(Co2+)2/3(Co3+)1/3PO4 phase. Two resonances are observed for Li2/3CoPO4 with intensity ratios of 2:1 and 1:1 in t ...[more]

PMID: 25960604

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Dataset Information

Identifying the Structure of the Intermediate, Li2/3CoPO4, Formed during Electrochemical Cycling of LiCoPO4.

Publications

Identifying the Structure of the Intermediate, Li<sub>2/3</sub>CoPO<sub>4</sub>, Formed during Electrochemical Cycling of LiCoPO<sub>4</sub>.

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