Evolution of microstructure and its relation to ionic conductivity in Li1+xAlxTi2−x(PO4)3

Hupfer, Thomas; Bucharsky, Ethel C.; Schell, Karl G.; Senyshyn, Anatoliy; Monchak, Mykhailo; Hoffmann, Michael J.; Ehrenberg, Helmut

doi:10.1016/j.ssi.2016.01.036

Cited by 74 publications

(50 citation statements)

References 21 publications

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“…Individual crystals show well developed faces and idiomorphic cube-like habitus. In a recent investigation (Hupfer et al, 2016) noted rapid grain growth of individual LATP crystals at 1100°C in a matrix of fine grained sample material already after 30 minutes of sintering up to a size of 100 m, however with distinct formation of cracks due to the stress induced by highly anisotropic thermal expansion, after 8 h of sintering these authors almost exclusively observed large grains > 100 m in their samples with multiple cracks. It should be noted that the crystals in this study were free of any crack.…”

Section: Synthesis and Mineral Chemistrymentioning

confidence: 95%

A single crystal X-ray and powder neutron diffraction study on NASICON-type Li1+Al Ti2−(PO4)3 (0 ≤ x ≤ 0.5) crystals: Implications on ionic conductivity

Redhammer

Rettenwander

Pristat

et al. 2016

Solid State Sciences

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Single crystals of NASICON-type material Li 1+x Ti 2-x Al x (PO 4) 3 (LATP) with 0 ≤ x ≤ 0.5 were successfully grown using long-term sintering techniques. Sample material was studied by chemical analysis, single crystal X-ray and neutron diffraction. The Ti 4+ replacement scales very well with the Al 3+ and Li + incorporation. The additional Li + thereby enters the M3 cavity of the NASICON framework at x, y, z ~ (0.07, 0.34, 0.09) and is regarded to be responsible for the enhanced Li + conduction of LATP as compared to Al-free LTP. Variations in structural parameters, associated with the Ti 4+ substitution with Al 3+ + Li + will be discussed in detail in this paper.

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Section: Synthesis and Mineral Chemistrymentioning

confidence: 95%

A single crystal X-ray and powder neutron diffraction study on NASICON-type Li1+Al Ti2−(PO4)3 (0 ≤ x ≤ 0.5) crystals: Implications on ionic conductivity

Redhammer

Rettenwander

Pristat

et al. 2016

Solid State Sciences

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“…7(c), it seems still well connected to the surrounding grains, so it might aid in the densification of the material as discussed in Refs. [15,18,20]. Cracks within LATP grains are also observed in grains that are not directly connected to AlPO 4 .…”

Section: Combined Clsm and Sem Of Latpmentioning

confidence: 99%

“…Aono et al [6,16] demonstrated that partially substituting Ti with trivalent metal ions, Li 1+x M x Ti 2-x (PO 4 ) 3 (M = Al, Sc, Y, La, Ga, Fe, In, Lu, or Cr) enhances the conductivity for x around 0.3 for all M 3+ ions except for Cr. Such a substitution affects both on the ionic conductivity within the crystal structure [19] and the microstructure of the ceramic pellet [7,16,20,21]. The conduction pathways in the NASICON structure was elucidated with neutron scattering [19].…”

Section: Introduction mentioning

confidence: 99%

“…The influence of processing parameters and secondary phases on the ionic conductivity was studied by many groups [7,20,21,25,26]. Crack formation in LATP grains was mainly observed in larger grains and at higher sintering temperatures by Hupfer et al [20]. Cracks were found to originate at the interface of LATP grains and AlPO 4 secondary phase by Waetzig et al [26].…”

Section: Introduction mentioning

confidence: 99%

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Combined quantitative microscopy on the microstructure and phase evolution in Li1.3Al0.3Ti1.7(PO4)3 ceramics

Gunduz

Schierholz

et al. 2020

J Adv Ceram

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Lithium aluminum titanium phosphate (LATP) is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries. In ceramic processing, the presence of secondary phases and porosity play an important role. In a presence of more than one secondary phase and pores, image analysis must tackle the difficulties about distinguishing between these microstructural features. In this study, we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100 ℃ by image segmentation based on energy-dispersive X-ray spectroscopy (EDS) elemental maps combined with quantitative analysis of LATP grains. We found aluminum phosphate (AlPO 4) and another phosphate phase ((Li x)P y O z). The amount of these phases changes with sintering temperature. First, since the grains act as an aluminum source for AlPO 4 formation, the aluminum content in the LATP grains decreases. Second, the amount of secondary phase changes from more (Li x)P y O z at 950 ℃ to mainly AlPO 4 at 1100 ℃ sintering temperature. We also used scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) to study the evolution of the LATP grains and AlPO 4 , and LATP grain size increases with sintering temperature. In addition, transmission electron microscopy (TEM) was used for the determination of grain boundary width and to identify the amorphous structure of AlPO 4 .

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“…The latter, with an optimized composition of Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , is water stable and exhibits a conductivity of 7 x 10 4 S.cm -1 at ambient temperature and a theoretical Ohmic resistance of 14 .cm² for a 100 mthick electrolyte [11]. The ionic conductivity of LATP ceramic electrolytes is strongly influenced by their microstructures (porosity, grain size, secondary phases…), which are controlled by the processing step [14]. For instance, because of the strong thermal expansion anisotropy of LATP, numerous microcracks are generated when the grain size is higher than a critical value, estimated to be around 1.6 m [15].…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

Hallopeau

Brégiroux

Rousse

et al. 2018

Journal of Power Sources

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Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) materials are made of a threedimensional framework of TiO 6 octahedra and PO 4 tetrahedra, which provides several positions for Li + ions. The resulting high ionic conductivity is promising to yield electrolytes for all-solid-state Li-ion batteries. In order to elaborate dense ceramics, conventional sintering methods often use high temperature ( 1000°C) with long dwelling times (several hours) to achieve high relative density ( 90%).In this work, an innovative synthesis and processing approach is proposed. A fast and easy processing technique called microwave-assisted reactive sintering is used to both synthesize and sinter LATP ceramics with suitable properties in one single step. Pure and crystalline LATP ceramics can be achieved in only 10 min at 890 °C starting from amorphous, compacted LATP's precursors powders. Despite a relative density of 88%, the ionic conductivity measured at ambient temperature (3.15 x 10 -4 S.cm -1 ) is among the best reported so far. The study of the activation energy for Li + conduction confirms the high quality of the ceramic (purity and crystallinity) achieved by using this new approach, thus emphasizing its interest for making ion-conducting ceramics in a simple and fast way.

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Evolution of microstructure and its relation to ionic conductivity in Li1+xAlxTi2−x(PO4)3

Cited by 74 publications

References 21 publications

A single crystal X-ray and powder neutron diffraction study on NASICON-type Li1+Al Ti2−(PO4)3 (0 ≤ x ≤ 0.5) crystals: Implications on ionic conductivity

A single crystal X-ray and powder neutron diffraction study on NASICON-type Li1+Al Ti2−(PO4)3 (0 ≤ x ≤ 0.5) crystals: Implications on ionic conductivity

Combined quantitative microscopy on the microstructure and phase evolution in Li1.3Al0.3Ti1.7(PO4)3 ceramics

Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

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