Temperature-Dependent Structural Changes of Na2Mn3(P2O7)2 Phase in NaLiMnP2O7 Mixed Phase Compound

Saulius Daugėla; Tomas Šalkus; Algimantas Kežionis; Antonija Dindune; Dagnija Valdniece; Tomasz Karol Pietrzak; Artūras Žalga; Antanas Feliksas Orliukas

doi:10.1080/10584587.2021.1921539

Temperature-Dependent Structural Changes of Na₂Mn₃(P₂O₇)₂ Phase in NaLiMnP₂O₇ Mixed Phase Compound

Saulius Daugėla^*
, Tomas Šalkus
, Algimantas Kežionis
, Antonija Dindune
, Dagnija Valdniece
, Tomasz Karol Pietrzak
, Artūras Žalga
, Antanas Feliksas Orliukas

^*Corresponding author for this work

Vilnius University
Riga Technical University
Warsaw University of Technology

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

Abstract

XRD measurements revealed that the investigated NaLiMnP₂O₇ compound consists of two phases: Na₂Mn₃(P₂O₇)₂ and LiMnPO₄. We found by XRD measurements that at 313 K Na₂Mn₃(P₂O₇)₂ shows the triclinic symmetry of the compound (space group P-1), while LiMnPO₄ phase showed the orthorhombic crystal symmetry (space group Pnma). The phase change between 773 K and 813 K was proved by thermal XRD, impedance spectroscopy and DTA analysis. No evident changes of peak intensities in thermal XRD were observed for LiMnPO₄ phase. The impedance of NaLiMnP₂O₇ ceramics was measured at different temperatures and the total ionic conductivity of the compound was found to be of 5.3 × 10⁻⁹ S/m at 400 K on heating stage and only slightly higher on cooling stage. However, the conductivity value at 800 K was much higher–about 1.45 S/m on both stages. The step-like phase transition resulted in the conductivity increase of about 3 orders of magnitude in a narrow range of temperature. The ionic transference number was found to be 0.91 at room temperature. The XRD spectra and conductivity analysis of synthesised two separate phases showed that the phase transition takes place only in Na₂Mn₃(P₂O₇)₂ ceramics.

Original language	English
Pages (from-to)	100-109
Number of pages	10
Journal	Integrated Ferroelectrics
Volume	220
Issue number	1
DOIs	https://doi.org/10.1080/10584587.2021.1921539
Publication status	Published - 2021
Externally published	Yes

Keywords

Ceramics
impedance spectroscopy
sodium pyrophosphates
solid electrolytes

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10.1080/10584587.2021.1921539

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@article{dd13a48dbdd9478389bf0868b6b4108b,

title = "Temperature-Dependent Structural Changes of Na2Mn3(P2O7)2 Phase in NaLiMnP2O7 Mixed Phase Compound",

abstract = "XRD measurements revealed that the investigated NaLiMnP2O7 compound consists of two phases: Na2Mn3(P2O7)2 and LiMnPO4. We found by XRD measurements that at 313 K Na2Mn3(P2O7)2 shows the triclinic symmetry of the compound (space group P-1), while LiMnPO4 phase showed the orthorhombic crystal symmetry (space group Pnma). The phase change between 773 K and 813 K was proved by thermal XRD, impedance spectroscopy and DTA analysis. No evident changes of peak intensities in thermal XRD were observed for LiMnPO4 phase. The impedance of NaLiMnP2O7 ceramics was measured at different temperatures and the total ionic conductivity of the compound was found to be of 5.3 × 10−9 S/m at 400 K on heating stage and only slightly higher on cooling stage. However, the conductivity value at 800 K was much higher–about 1.45 S/m on both stages. The step-like phase transition resulted in the conductivity increase of about 3 orders of magnitude in a narrow range of temperature. The ionic transference number was found to be 0.91 at room temperature. The XRD spectra and conductivity analysis of synthesised two separate phases showed that the phase transition takes place only in Na2Mn3(P2O7)2 ceramics.",

keywords = "Ceramics, impedance spectroscopy, sodium pyrophosphates, solid electrolytes",

author = "Saulius Daugėla and Tomas {\v S}alkus and Algimantas Ke{\v z}ionis and Antonija Dindune and Dagnija Valdniece and Pietrzak, \{Tomasz Karol\} and Artūras {\v Z}alga and Orliukas, \{Antanas Feliksas\}",

note = "Publisher Copyright: {\textcopyright} 2021 Taylor \& Francis Group, LLC.",

year = "2021",

doi = "10.1080/10584587.2021.1921539",

language = "English",

volume = "220",

pages = "100--109",

journal = "Integrated Ferroelectrics",

issn = "1058-4587",

publisher = "Taylor and Francis Ltd.",

number = "1",

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TY - JOUR

T1 - Temperature-Dependent Structural Changes of Na2Mn3(P2O7)2 Phase in NaLiMnP2O7 Mixed Phase Compound

AU - Daugėla, Saulius

AU - Šalkus, Tomas

AU - Kežionis, Algimantas

AU - Dindune, Antonija

AU - Valdniece, Dagnija

AU - Pietrzak, Tomasz Karol

AU - Žalga, Artūras

AU - Orliukas, Antanas Feliksas

PY - 2021

Y1 - 2021

N2 - XRD measurements revealed that the investigated NaLiMnP2O7 compound consists of two phases: Na2Mn3(P2O7)2 and LiMnPO4. We found by XRD measurements that at 313 K Na2Mn3(P2O7)2 shows the triclinic symmetry of the compound (space group P-1), while LiMnPO4 phase showed the orthorhombic crystal symmetry (space group Pnma). The phase change between 773 K and 813 K was proved by thermal XRD, impedance spectroscopy and DTA analysis. No evident changes of peak intensities in thermal XRD were observed for LiMnPO4 phase. The impedance of NaLiMnP2O7 ceramics was measured at different temperatures and the total ionic conductivity of the compound was found to be of 5.3 × 10−9 S/m at 400 K on heating stage and only slightly higher on cooling stage. However, the conductivity value at 800 K was much higher–about 1.45 S/m on both stages. The step-like phase transition resulted in the conductivity increase of about 3 orders of magnitude in a narrow range of temperature. The ionic transference number was found to be 0.91 at room temperature. The XRD spectra and conductivity analysis of synthesised two separate phases showed that the phase transition takes place only in Na2Mn3(P2O7)2 ceramics.

AB - XRD measurements revealed that the investigated NaLiMnP2O7 compound consists of two phases: Na2Mn3(P2O7)2 and LiMnPO4. We found by XRD measurements that at 313 K Na2Mn3(P2O7)2 shows the triclinic symmetry of the compound (space group P-1), while LiMnPO4 phase showed the orthorhombic crystal symmetry (space group Pnma). The phase change between 773 K and 813 K was proved by thermal XRD, impedance spectroscopy and DTA analysis. No evident changes of peak intensities in thermal XRD were observed for LiMnPO4 phase. The impedance of NaLiMnP2O7 ceramics was measured at different temperatures and the total ionic conductivity of the compound was found to be of 5.3 × 10−9 S/m at 400 K on heating stage and only slightly higher on cooling stage. However, the conductivity value at 800 K was much higher–about 1.45 S/m on both stages. The step-like phase transition resulted in the conductivity increase of about 3 orders of magnitude in a narrow range of temperature. The ionic transference number was found to be 0.91 at room temperature. The XRD spectra and conductivity analysis of synthesised two separate phases showed that the phase transition takes place only in Na2Mn3(P2O7)2 ceramics.

KW - Ceramics

KW - impedance spectroscopy

KW - sodium pyrophosphates

KW - solid electrolytes

UR - https://www.scopus.com/pages/publications/85120641550

U2 - 10.1080/10584587.2021.1921539

DO - 10.1080/10584587.2021.1921539

M3 - Article

AN - SCOPUS:85120641550

SN - 1058-4587

VL - 220

SP - 100

EP - 109

JO - Integrated Ferroelectrics

JF - Integrated Ferroelectrics

IS - 1

ER -

Temperature-Dependent Structural Changes of Na₂Mn₃(P₂O₇)₂ Phase in NaLiMnP₂O₇ Mixed Phase Compound

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Keywords

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