Solid-State Electrolytes: Revealing the Mechanisms of Li-Ion Conduction in Tetragonal and Cubic LLZO by First-Principles Calculations

Meier, Katharina; Laino, Teodoro; Curioni, A.

doi:10.1021/jp5002463

Cited by 189 publications

(243 citation statements)

References 59 publications

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“…These results are consistent with other simulation studies. 25,26,29 In the case of Ga atoms (for x = 0.30), their MSD starts to increase at 1200 K (Figure 5c). This onset temperature for Ga ion diffusion does not vary with respect to Ga content (see Figure S4 in the Supporting Information).…”

Section: +mentioning

confidence: 98%

“…The trajectory of the x = 0 case is in strong agreement with a recent analysis of neutron powder diffraction data 62 as well as several simulation studies. [25][26][27]29 To make a clear comparison with the x = 0.30 case, we chose an appropriate slab section to expose the full 2D plane view of Li pathway connectivity, such as plane (3 6 4), which is shown in blue in Figure 10a and 10c. As can be seen, pathway features such as junctions formed by Td sites (LiO 4 ) and density lobes formed by Oh sites (LiO 6 ) can be observed in detail (Figure 10b, d).…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

“…25 Meier et al further provided information to establish the difference between the Li + ion diffusion mechanism of the tetragonal and cubic phase through DFT-based MD and metadynamics simulations; the former has a fully collective nature or synchronous motion while the latter has an asynchronous motion governed by single-ion jumps and induced collective motion. 26 In another simulation using classical MD, with a BV-based Morse-type force field, Adams et al predicted that for the garnet Li 7−x La 3 (Zr 2−x M x )O 12 system (x = 0, 0.25; M = Ta 5+ , Nb 5+ ): (i) the lithium distribution just above the cubic phase transition closely resembles that in the tetragonal phase and that (ii) pentavalent doping can enhance ionic conductivity by increasing the vacancy concentration and by reducing local Li ordering. 27 Wang et al discovered through static energy minimization with Buckingham potentials, that the shape of energy probability distribution, can aid in unders t a n d i n g l i t h i u m d i s o r d e r / o r d e r e ff e c t s i n t h e Li 7−x La 3 Zr 2−x Ta x O 12 (x = 0−2) series.…”

Section: ■ Introductionmentioning

confidence: 99%

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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: +mentioning

confidence: 98%

Section: Chemistry Of Materialsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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

et al. 2015

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“…Jalem et al 24 identified a concerted Li + migration mechanism in cubic LLZO via AIMD simulations. Meier et al 108 compared the differences in Li + diffusion in tetragonal and cubic phases using a similar technique. In tetragonal LLZO, the Li + motion is of a fully synchronous collective nature requiring higher activation energy, whereas in cubic LLZO, because of the existence of unoccupied Li sites, the asynchronous collective motion of Li + caused by single-ion jumps leads to lower activation energy.…”

Section: Llzo Garnetmentioning

confidence: 99%

Computational studies of solid-state alkali conduction in rechargeable alkali-ion batteries

Deng

Ong

2016

NPG Asia Mater

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The facile conduction of alkali ions in a crystal host is of crucial importance in rechargeable alkali-ion batteries, the dominant form of energy storage today. In this review, we provide a comprehensive survey of computational approaches to study solid-state alkali diffusion. We demonstrate how these methods have provided useful insights into the design of materials that form the main components of a rechargeable alkali-ion battery, namely the electrodes, superionic conductor solid electrolytes and interfaces. We will also provide a perspective on future challenges and directions. The scope of this review includes the monovalent lithium-and sodium-ion chemistries that are currently of the most commercial interest. NPG Asia Materials (2016) 8, e254; doi:10.1038/am.2016.7; published online 25 March 2016 INTRODUCTIONThe facile conduction of alkali ions in a crystal is of critical importance in energy storage. Today, the dominant form of energy storage in consumer electronics is the rechargeable lithium-ion (Li-ion) battery, 1-5 a device that functions entirely on the basis of the reversible transport of Li + ions. With one of the highest energy densities of known energy storage technologies, Li-ion batteries are finding increasingly large-scale applications in electrified transportation and grid storage. In recent years, there has also been a resurgence of interest in rechargeable sodium-ion (Na-ion) batteries, 6-12 which function on the same basic principle but with Na + instead of Li + because of concerns regarding the abundance and cost of lithium. Figure 1 shows a representation of a rechargeable alkali-ion battery. The typical electrode in an alkali-ion battery is an intercalation compound, which, as the name implies, stores alkali ions by inserting them into its crystal structure in a topotactic manner. During discharge, A + ions are transported from the anode, through the electrolyte and into the cathode. The reverse happens during charge. Throughout this review, we will adopt the customary terminology of defining the 'cathode' as the positive electrode during discharge, even though the formal definition of the cathode changes depending on whether the charging or discharging process is being referred to. Current cathodes are typically transition metal oxides, and the insertion/removal of each A + in the cathode is accompanied by the concomitant reduction/oxidation of a transition metal ion to accommodate the compensating insertion/removal of an electron. Graphitic carbon is the most common anode.The performance of a rechargeable alkali-ion battery depends crucially on the ease with which alkali ions move in the host crystal of the cathode and anode, in the electrolyte, and in the electrodeelectrolyte interface. Poor alkali transport in any part of the battery

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“…Although not reported yet, this process should be correlated to electromigration mitigated effects such as carbon insertion [17], Frenkel pair nucleation [26] or oxygen gradient in UO 2+x [27]. Moreover the extremely fast cooling rate used in SPS sintering could have quenched the system into a metastable state with highly disordered ionic distribution, favoring high Li mobility [5,25,[28][29].…”

mentioning

confidence: 96%

Bulk Li mobility enhancement in Spark Plasma Sintered Li(7−3x)AlxLa3Zr2O12 garnet

Castillo

Charpentier

Rapaud

et al. 2018

Ceramics International

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Li (7−3x) Al x La 3 Zr 2 O 12 (LLAZO) Al-doped garnets display high ionic conductivity in the range of ~10 -4 S.cm -1 at room temperature and are thus envisioned for future solid-state batteries. In this study, LLAZO powders with two doping levels were synthetized using a solid-state route and sintered using Spark Plasma Sintering (SPS). Both pristine and SPS crushed pellet powders were investigated using X-Ray Diffraction (XRD) confirming the formation of the most conducting cubic phase. Ionic conductivity measurements were performed using electrochemical impedance spectroscopy. Li and Al distributions among available sites were identified using Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) experiments, and Li mobility was explored using 7 Li static wideline NMR spectroscopy.Results show that SPS treatment, beyond producing highly densified pellets, mainly modifies Al distribution and strongly impacts the bulk Li + mobility.

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Solid-State Electrolytes: Revealing the Mechanisms of Li-Ion Conduction in Tetragonal and Cubic LLZO by First-Principles Calculations

Cited by 189 publications

References 59 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

Computational studies of solid-state alkali conduction in rechargeable alkali-ion batteries

Bulk Li mobility enhancement in Spark Plasma Sintered Li(7−3x)AlxLa3Zr2O12 garnet

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Solid-State Electrolytes: Revealing the Mechanisms of Li-Ion Conduction in Tetragonal and Cubic LLZO by First-Principles Calculations

Cited by 189 publications

References 59 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

Computational studies of solid-state alkali conduction in rechargeable alkali-ion batteries

Bulk Li mobility enhancement in Spark Plasma Sintered Li(7−3x)AlxLa3Zr2O12 garnet

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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