A microcontact impedance study on NASICON-type Li1+xAlxTi2-x(PO4)3 (0 ≤ x ≤ 0.5) single crystals

D. Rettenwander; A. Welzl; S. Pristat; F. Tietz; S. Taibl; G. J. Redhammer; J. Fleig

doi:10.1039/c5ta08545d

A microcontact impedance study on NASICON-type Li_1+xAl_xTi_2-x(PO₄)₃ (0 ≤ x ≤ 0.5) single crystals

D. Rettenwander^*, A. Welzl, S. Pristat, F. Tietz, S. Taibl, G. J. Redhammer, J. Fleig

^*Corresponding author for this work

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

Abstract

We successfully demonstrated the applicability of microcontact impedance spectroscopy (MC IS) on Li⁺ conducting solid electrolytes and measured the Li⁺ bulk conductivity (σ_b) of LiTi₂(PO₄)₃ (LTP) and Li_1+xAl_xTi_2-x(PO₄)₃ (LATP) single crystals independent of microstructural effects (e.g., grain boundaries, pores, and density). The crystals had a size of about 100 μm in each direction and crystallized with NASICON-type structure (R3¯c). Finite element calculations were performed to validate the impedance data analysis. A strong increase in σ_b in the order of three magnitudes (3.16 × 10^-6 to 1.73 × 10^-3 S cm^-1) was found after incorporating 0.1 mol Al³⁺ per formula unit into LTP. Moreover, since the crystal structural changes are almost linear in the LATP system up to x = 0.5, the increase of σ_b is most probably related to additional Li⁺ sites at the M₃ (36f) position. The additional Li⁺ leads to a displacement of Li⁺ occupying the M₁ (6b) sites towards the nearest-neighboring M₃ position, and therefore opens the fast-conducting pathway within the NASICON structure. A significant change in σ_b was also observed as the Al³⁺ content further increased (x = 0.1 to 0.5). The highest σ_b value of 5.63 × 10^-3 S cm^-1 was obtained for samples with x = 0.4.

Original language	English
Pages (from-to)	1506-1513
Number of pages	8
Journal	Journal of Materials Chemistry A
Volume	4
Issue number	4
DOIs	https://doi.org/10.1039/c5ta08545d
Publication status	Published - 17 Dec 2015
Externally published	Yes

ASJC Scopus subject areas

General Chemistry
Renewable Energy, Sustainability and the Environment
General Materials Science

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This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1039/c5ta08545d

Cite this

@article{c2d592b8600a43f4971878edf7ea7d0b,

title = "A microcontact impedance study on NASICON-type Li1+xAlxTi2-x(PO4)3 (0 ≤ x ≤ 0.5) single crystals",

abstract = "We successfully demonstrated the applicability of microcontact impedance spectroscopy (MC IS) on Li+ conducting solid electrolytes and measured the Li+ bulk conductivity (σb) of LiTi2(PO4)3 (LTP) and Li1+xAlxTi2-x(PO4)3 (LATP) single crystals independent of microstructural effects (e.g., grain boundaries, pores, and density). The crystals had a size of about 100 μm in each direction and crystallized with NASICON-type structure (R3¯c). Finite element calculations were performed to validate the impedance data analysis. A strong increase in σb in the order of three magnitudes (3.16 × 10-6 to 1.73 × 10-3 S cm-1) was found after incorporating 0.1 mol Al3+ per formula unit into LTP. Moreover, since the crystal structural changes are almost linear in the LATP system up to x = 0.5, the increase of σb is most probably related to additional Li+ sites at the M3 (36f) position. The additional Li+ leads to a displacement of Li+ occupying the M1 (6b) sites towards the nearest-neighboring M3 position, and therefore opens the fast-conducting pathway within the NASICON structure. A significant change in σb was also observed as the Al3+ content further increased (x = 0.1 to 0.5). The highest σb value of 5.63 × 10-3 S cm-1 was obtained for samples with x = 0.4.",

author = "D. Rettenwander and A. Welzl and S. Pristat and F. Tietz and S. Taibl and Redhammer, {G. J.} and J. Fleig",

year = "2015",

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doi = "10.1039/c5ta08545d",

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T1 - A microcontact impedance study on NASICON-type Li1+xAlxTi2-x(PO4)3 (0 ≤ x ≤ 0.5) single crystals

AU - Rettenwander, D.

AU - Welzl, A.

AU - Pristat, S.

AU - Tietz, F.

AU - Taibl, S.

AU - Redhammer, G. J.

AU - Fleig, J.

PY - 2015/12/17

Y1 - 2015/12/17

N2 - We successfully demonstrated the applicability of microcontact impedance spectroscopy (MC IS) on Li+ conducting solid electrolytes and measured the Li+ bulk conductivity (σb) of LiTi2(PO4)3 (LTP) and Li1+xAlxTi2-x(PO4)3 (LATP) single crystals independent of microstructural effects (e.g., grain boundaries, pores, and density). The crystals had a size of about 100 μm in each direction and crystallized with NASICON-type structure (R3¯c). Finite element calculations were performed to validate the impedance data analysis. A strong increase in σb in the order of three magnitudes (3.16 × 10-6 to 1.73 × 10-3 S cm-1) was found after incorporating 0.1 mol Al3+ per formula unit into LTP. Moreover, since the crystal structural changes are almost linear in the LATP system up to x = 0.5, the increase of σb is most probably related to additional Li+ sites at the M3 (36f) position. The additional Li+ leads to a displacement of Li+ occupying the M1 (6b) sites towards the nearest-neighboring M3 position, and therefore opens the fast-conducting pathway within the NASICON structure. A significant change in σb was also observed as the Al3+ content further increased (x = 0.1 to 0.5). The highest σb value of 5.63 × 10-3 S cm-1 was obtained for samples with x = 0.4.

AB - We successfully demonstrated the applicability of microcontact impedance spectroscopy (MC IS) on Li+ conducting solid electrolytes and measured the Li+ bulk conductivity (σb) of LiTi2(PO4)3 (LTP) and Li1+xAlxTi2-x(PO4)3 (LATP) single crystals independent of microstructural effects (e.g., grain boundaries, pores, and density). The crystals had a size of about 100 μm in each direction and crystallized with NASICON-type structure (R3¯c). Finite element calculations were performed to validate the impedance data analysis. A strong increase in σb in the order of three magnitudes (3.16 × 10-6 to 1.73 × 10-3 S cm-1) was found after incorporating 0.1 mol Al3+ per formula unit into LTP. Moreover, since the crystal structural changes are almost linear in the LATP system up to x = 0.5, the increase of σb is most probably related to additional Li+ sites at the M3 (36f) position. The additional Li+ leads to a displacement of Li+ occupying the M1 (6b) sites towards the nearest-neighboring M3 position, and therefore opens the fast-conducting pathway within the NASICON structure. A significant change in σb was also observed as the Al3+ content further increased (x = 0.1 to 0.5). The highest σb value of 5.63 × 10-3 S cm-1 was obtained for samples with x = 0.4.

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