Synthesis and high Li-ion conductivity of Ga-stabilized cubic Li7La3Zr2O12

Wolfenstine, J.; Ratchford, Joshua B.; Rangasamy, Ezhiyl; Sakamoto, Jeffrey; Allen, J. S.

doi:10.1016/j.matchemphys.2012.03.054

Cited by 186 publications

(115 citation statements)

References 21 publications

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“…Geiger et al [17] have suggested that Al substitutes for Li and thereby stabilizes the cubic phase. A similar stabilization of cubic phase is observed with Ga substitution, where Ga substitutes for Li [20,21]. One hypothesis is that super-valent cation substitution reduces the Li content and/or increases Li vacancy concentration, while maintaining oxygen stoichiometry, and hence stabilizes the cubic phase [16,17,19].…”

Section: Introductionmentioning

confidence: 76%

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The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

Rangasamy¹,

Wolfenstine²,

Allen³

et al. 2012

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Section: Introductionmentioning

confidence: 76%

“…One hypothesis is that super-valent cation substitution reduces the Li content and/or increases Li vacancy concentration, while maintaining oxygen stoichiometry, and hence stabilizes the cubic phase [16,17,19]. In KrogereVink notation [24], the relationship for Al and Ga substitution for Li are as follows [17,19,21]:…”

Section: Introductionmentioning

confidence: 99%

The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

Rangasamy¹,

Wolfenstine²,

Allen³

et al. 2012

Self Cite

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“…Also, Ga 3+ doping appears not to cause any severe lattice constant change; several experimental studies related to Li pathway blocking dopants for LLZrO have arrived at the same conclusion. 13,38,42,44,54 We also checked whether Ga can promote a more open local Li pathway by analyzing the void space when Li atoms are completely removed in the model cells. The Zeo++ software was used to perform geometry-based analysis of structure and topology of the void space inside the LLZrO framework; it can determine the bottleneck size by calculating the largest pore diameter along the Li pathway.…”

Section: +mentioning

confidence: 99%

“…58 A further example of this variability are the results of Wolfenstine et al in which they achieved ∼91% dense samples with 0.25 mol p.f.u of Ga 3+ , resulting in a total conductivity of 3.5 × 10 −4 S/cm, much lower than the 10 −3 S/cm range. 54 El Shinawi et al 45 substituted up to 1.0 mol p.f.u. and achieved 92.5% density; they identified an increasing trend in the measured conductivity to about 5.4 × 10 −4 S/cm, although still <1 × 10 −3 S/cm.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

Insights into the Lithium-Ion Conduction Mechanism of Garnet-Type Cubic Li₅La₃Ta₂O₁₂ by ab-Initio Calculations

et al. 2015

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Garnet-type Li 7 La 3 Zr 2 O 12 (LLZrO) is a candidate solid electrolyte material that is now being intensively optimized for application in commercially competitive solid state Li + ion batteries. In this study we investigate, by forcefield-based simulations, the effects of Ga 3+ doping in LLZrO. We confirm the stabilizing effect of Ga 3+ on the cubic phase. We also determine that Ga 3+ addition does not lead to any appreciable structural distortion. Li site connectivity is not significantly deteriorated by the Ga 3+ addition (>90% connectivity retained up to x = 0.30 in Li 7−3x Ga x La 3 Zr 2 O 12 ). Interestingly, two compositional regions are predicted for bulk Li + ion conductivity in the cubic phase: (i) a decreasing trend for 0 ≤ x ≤ 0.10 and (ii) a relatively flat trend for 0.10 < x ≤ 0.30. This conductivity behavior is explained by combining analyses using percolation theory, van Hove space time correlation, the radial distribution function, and trajectory density. ■ INTRODUCTIONSolid electrolytes with high lithium ionic conductivity are now being actively investigated for application in commercially competitive all-solid-state rechargeable lithium-ion batteries. Among them, Li-based garnet oxides have shown promise for meeting the much needed safety and reliability requirements of today's commercial lithium ion batteries.1−7 One of the garnet compositions being considered is the cubic Li 7 La 3 Zr 2 O 12 (LLZrO), this is due to its stability with elemental lithium and a total conductivity on the order of 10 −4 S/cm. 2 Its structure is usually defined in the Ia3̅ d space group with Li cations partiallly occupying 24d tetrahedral (Td) and 48g/96h octahedral (Oh) sites, La cations fully occupying 24c dodecahedral sites, Zr cations fully occupying 16a octahedral sites, and O anions fully occupying the 96h sites (see Figure 1). However, a more stable tetragonal symmetry (I4 1 /acd) has also been reported to exist at room temperature, with Li ordering in three crystallographic sites: one at the 8a site, which forms a subset of the cubic garnet 24d site, and the other two highly distorted 16f and 32g sites which, when combined, are equivalent to the cubic garnet 48g/96h sites. 8,9 This ordering is responsible for the low bulk Li + ion conductivity measured for tetragonal LLZrO, a value on the order of 1 × 10 −6 S/cm at room tempertaure.

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“…Although several researchers reported improved lithium-ion conductivity of LLZO by Ga-doping [18][19][20][21]24 , the reported lithium-ion conductivity was only ~10 mol.% excess of Li 2 CO 3 was used to compensate the lithium loss during high temperature calcination. The powders were ball-milled for 15 h, heated in air at 900 °C for 6 h, followed by ball-milling for another 15 h. The powders were then cold isostatically pressed into pellets at 250 MPa and sintered at 1100 °C for 24 h in air.…”

Section: Introductionmentioning

confidence: 99%

Gallium-Doped Li₇La₃Zr₂O₁₂ Garnet-Type Electrolytes with High Lithium-Ion Conductivity

Chen

et al. 2017

ACS Appl. Mater. Interfaces

277

217

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Owing to their high conductivity, crystalline Li 7-3x Ga x La 3 Zr 2 O 12 garnets are promising electrolytes for allsolid-state lithium-ion batteries. Herein, the influence of Ga doping on the phase, lithium-ion distribution, and conductivity of Li 7-3x Ga x La 3 Zr 2 O 12 garnets is investigated, with the determined concentration and mobility of lithium ions shedding light on the origin of the high conductivity of Li 7-3x Ga x La 3 Zr 2 O 12 . When the Ga concentration exceeds 0.20 Ga per formula unit, the garnet-type material is found to assume a cubic structure, but lower Ga concentrations result in the coexistence of cubic and tetragonal phases. Most lithium within Li 7-3x Ga x La 3 Zr 2 O 12 is found to reside at the octahedral 96h site, away from the central octahedral 48g site, while the remaining lithium resides at the tetrahedral 24d site. Such kind of lithium distribution leads to high lithium-ion mobility, which is the origin of the high conductivity; the highest lithium-ion conductivity of 1.46 mS/cm at 25 °C is found to be achieved for Li 7-3x Ga x La 3 Zr 2 O 12 at x = 0.25. Additionally, there are two lithium-ion migration pathways in the Li 7-3x Ga x La 3 Zr 2 O 12 garnets: 96h-96h and 24d-96h-24d, but the lithium ions transporting through the 96h-96h pathway determine the overall conductivity. Disciplines Engineering | Physical Sciences and Mathematics

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Synthesis and high Li-ion conductivity of Ga-stabilized cubic Li7La3Zr2O12

Cited by 186 publications

References 21 publications

The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

Insights into the Lithium-Ion Conduction Mechanism of Garnet-Type Cubic Li₅La₃Ta₂O₁₂ by ab-Initio Calculations

Gallium-Doped Li₇La₃Zr₂O₁₂ Garnet-Type Electrolytes with High Lithium-Ion Conductivity

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Synthesis and high Li-ion conductivity of Ga-stabilized cubic Li7La3Zr2O12

Cited by 186 publications

References 21 publications

The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

The Effect of 24c-site (A) Cation Substitution on the Tetragonal-Cubic Phase Transition in Li7-xLa3-xAxZr2O12 Garnet-Based Ceramic Electrolyte

Insights into the Lithium-Ion Conduction Mechanism of Garnet-Type Cubic Li5La3Ta2O12 by ab-Initio Calculations

Gallium-Doped Li7La3Zr2O12 Garnet-Type Electrolytes with High Lithium-Ion Conductivity

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Insights into the Lithium-Ion Conduction Mechanism of Garnet-Type Cubic Li₅La₃Ta₂O₁₂ by ab-Initio Calculations

Gallium-Doped Li₇La₃Zr₂O₁₂ Garnet-Type Electrolytes with High Lithium-Ion Conductivity