Lithium ion transport properties of high conductive tellurium substituted Li7La3Zr2O12 cubic lithium garnets

Deviannapoorani, C.; Dhivya, L.; Ramakumar, S.; Murugan, Ramaswamy

doi:10.1016/j.jpowsour.2013.03.166

Cited by 199 publications

(125 citation statements)

References 32 publications

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“…Optimization efforts have focused on obtaining the cubic phase by promoting disorder across the Li sublattice; dopant incorporation is typically employed, targeting the framework cation sites (i.e., La and Zr). Some notable improvements were reported for Te-doped LLZrO (1.02 × 10 −3 S/cm), 15 Tadoped LLZrO (1.0 × 10 −3 S/cm), 16−19 Nb-doped LLZrO (8.0 × 10 −4 S/cm), 20 Sb-doped LLZrO (7.7 × 10 −4 S/cm), 21 and Sr-doped LLZrO (5.0 × 10 −4 S/cm). 22 Simultaneous substitution was also explored in the series Li 7+x−y (La 3−x A x )-(Zr 2−y Nb y )O 12 (where A is an alkali earth metal) and has shown that an optimum lattice parameter at a constant lithium content of 6.5 per formula unit (p.f.u.)…”

Section: ■ Introductionmentioning

confidence: 84%

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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Section: ■ Introductionmentioning

confidence: 84%

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

et al. 2015

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“…Solid-state batteries using solid electrolytes such as polymers 6–8 , oxides 9–12 , or sulfides 13–16 are hence promising for next-generation lithium-ion batteries. The application requires solid electrolytes with good chemical compatibility, high Li-ion conductivity and a wide electrochemical stability window.…”

Section: Introductionmentioning

confidence: 99%

Advanced sulfide solid electrolyte by core-shell structural design

et al. 2018

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Solid electrolyte is critical to next-generation solid-state lithium-ion batteries with high energy density and improved safety. Sulfide solid electrolytes show some unique properties, such as the high ionic conductivity and low mechanical stiffness. Here we show that the electrochemical stability window of sulfide electrolytes can be improved by controlling synthesis parameters and the consequent core-shell microstructural compositions. This results in a stability window of 0.7–3.1 V and quasi-stability window of up to 5 V for Li-Si-P-S sulfide electrolytes with high Si composition in the shell, a window much larger than the previously predicted one of 1.7–2.1 V. Theoretical and computational work explains this improved voltage window in terms of volume constriction, which resists the decomposition accompanying expansion of the solid electrolyte. It is shown that in the limiting case of a core-shell morphology that imposes a constant volume constraint on the electrolyte, the stability window can be further opened up. Advanced strategies to design the next-generation sulfide solid electrolytes are also discussed based on our understanding.

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“…1,2 These garnet materials are also stable against reactions with metallic lithium electrodes and are stable in air at ambient and high temperatures. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The most extensively studied members of the lithium conducting garnets are the cubic Li 7 La 3 Zr 2 O 12 (LLZ) based materials due to their high ionic conductivity >10 À4 S cm À1 at RT. [1][2][3][4][5] Extensive work has been devoted to optimize the ionic conductivity of garnet materials, which could be achieved by chemical substitutions and structural modications.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the concentration and mobility of mobile Li⁺ in the cubic garnet-type Li₇La₃Zr₂O₁₂

Ahmad

2015

RSC Adv.

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LLZ) lithium ion conductors with the garnet-like structure are promising candidates for applications in all solid-state lithium ion batteries. Due to the complexity of the structure and the distribution of Li + , it was difficult to get information on the true concentration of mobile Li + , n c , and their mobility. In this report, we estimate for the first time the values of n c from the analysis of the conductivity spectra at different temperatures. We found that only a small fraction of Li + contributes to the conduction process. n c is found to be independent of temperature with an average value of 3.17 Â 10 21 cm À3 , which represents 12.3% only of the total Li + content in LLZ garnets. Comparing the conduction parameters of LLZ with Li 6 BaLa 2 Ta 2 O 12 (LBLT) and Li 5 La 3 Ta 2 O 12 (LLT) garnets indicates that the mobility of Li + plays a prominent role in the conductivity enhancement in LLZ garnet materials. The diffusion coefficient of LLZ at room temperature has a value of 1.33 Â 10 À8 cm 2 s À1 , which is comparable with other fast Li + conductors.

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Lithium ion transport properties of high conductive tellurium substituted Li7La3Zr2O12 cubic lithium garnets

Cited by 199 publications

References 32 publications

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

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

Advanced sulfide solid electrolyte by core-shell structural design

Estimation of the concentration and mobility of mobile Li⁺ in the cubic garnet-type Li₇La₃Zr₂O₁₂

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Lithium ion transport properties of high conductive tellurium substituted Li7La3Zr2O12 cubic lithium garnets

Cited by 199 publications

References 32 publications

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

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

Advanced sulfide solid electrolyte by core-shell structural design

Estimation of the concentration and mobility of mobile Li+ in the cubic garnet-type Li7La3Zr2O12

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

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

Estimation of the concentration and mobility of mobile Li⁺ in the cubic garnet-type Li₇La₃Zr₂O₁₂