Native Defect Concentrations in NaAlH4 and Na3AlH6

Michel, Kyle; Ozoliņš, Vidvuds

doi:10.1021/jp203672u

Cited by 26 publications

(44 citation statements)

References 55 publications

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“…The method proceeds as follows (Figure S10): (i) Identify all possible insertion sites in the original CuS structure using an in-house code. [56][57][58] CuS adopts a hexagonal covellite structure with unoccupied inlayer (A) and interlayer (B) as shown in Figure S10a. A supercell containing all symmetrically distinct configurations with Enum [59][60][61] for a series of compositions Li x ◻ 2-x CuS (0 < x < 2, ◻ denoting vacancy).…”

Section: Methodsmentioning

confidence: 99%

Kinetically-Driven Phase Transformation during Lithiation in Copper Sulfide Nanoflakes

Yao

Hwang

et al. 2017

Nano Lett.

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Two-dimensional (2D) transition metal chalcogenides have been widely studied and utilized as electrode materials for lithium ion batteries due to their unique layered structures to accommodate reversible lithium insertion. Real-time observation and mechanistic understanding of the phase transformations during lithiation of these materials are critically important for improving battery performance by controlling structures and reaction pathways. Here, we use in situ transmission electron microscopy methods to study the structural, morphological, and chemical evolutions in individual copper sulfide (CuS) nanoflakes during lithiation. We report a highly kinetically driven phase transformation in which lithium ions rapidly intercalate into the 2D van der Waals-stacked interlayers in the initial stage, and further lithiation induces the Cu extrusion via a displacement reaction mechanism that is different from the typical conversion reactions. Density functional theory calculations have confirmed both the thermodynamically favored and the kinetically driven reaction pathways. Our findings elucidate the reaction pathways of the Li/CuS system under nonequilibrium conditions and provide valuable insight into the atomistic lithiation mechanisms of transition metal sulfides in general.

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Section: Methodsmentioning

confidence: 99%

Kinetically-Driven Phase Transformation during Lithiation in Copper Sulfide Nanoflakes

Yao

Hwang

et al. 2017

Nano Lett.

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“…Computational studies based on NEB methods have significantly added to understanding of the static energy landscape of ion migration pathways in electrode and SE materials. 16,[23][24][25][26][27][28] In addition, the diffusion pathway and energy barriers obtained from NEB calculations can be used as input for kinetic Monte Carlo calculations to obtain the overall diffusivity, conductivity, and activation energy in ion-conducting materials with non-dilute carrier concentrations. [29][30][31][32] However, for many SICs, such as LGPS and LLZO, with highly disordered Li-ion sublattices, NEB calculations require a priori guesses of ion-hopping sites and pathways and so are often more complicated and involved to perform.…”

Section: Ab Initio Molecular Dynamics Simulationmentioning

confidence: 99%

Computation-Accelerated Design of Materials and Interfaces for All-Solid-State Lithium-Ion Batteries

Nolan

Zhu

et al. 2018

Joule

286

230

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The all-solid-state lithium-ion battery is a promising next-generation battery technology. However, the realization of all-solid-state batteries is impeded by limited understanding of solid electrolyte materials and solid electrolyte-electrode interfaces. In this review, we present an overview of recently developed computation techniques and their applications in understanding and advancing materials and interfaces in all-solid-state batteries. We review the role of ab initio molecular dynamics simulations in studying fast ion conductors and discuss the capabilities of thermodynamic calculations powered by materials databases for identifying the chemical and electrochemical stability of solid electrolyte materials and solid electrolyte-electrode interfaces. We highlight the computational studies in the design and discovery of new solid electrolyte materials and outline design guidelines for solid electrolytes and their interfaces. We conclude with discussion of future directions in computation techniques, materials development, and interface engineering for all-solid-state lithium-ion batteries.

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“…Na 3 AlH 6 has eleven inequivalent jumps attributed to the two symmetry‐inequivalent Na‐sites, Na1 (2 b ) and Na2 (4 e ), and the different orientation of [AlH 6 ] − unit . Michel and Ozolins revealed that the formation energy of the Na‐vacancy, V ′ Na , in Na1 site of Na 3 AlH 6 is lower than that in NaAlH 4 They also revealed that the Na‐vacancy diffusion coefficient in Na 3 AlH 6 is larger than that in NaAlH 4 in the temperature range from 250–400 K (The former and the latter have 1.19 × 10 −12 and 4.96 × 10 −11 m 2 s −1 , respectively, at 400 K, evaluated by the kinetic Monte Carlo simulations) . These might result in the higher Na‐ionic conductivity in Na 3 AlH 6 than in NaAlH 4 .…”

Section: Fast Na‐ionic Conductor Developmentmentioning

confidence: 99%

Complex Hydrides for Electrochemical Energy Storage

Unemoto

Matsuo

Orimo

2014

Adv Funct Materials

195

226

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Complex hydrides have energy storage-related functions such as i) solid-state hydrogen storage, ii) electrochemical Li storage, and iii) fast Li-and Naionic conductions. Here, recent progress on the development of fast Li-ionic conductors based on the complex hydrides is reported. The validity of using them as electrolytes in all-solid-state lithium rechargeable batteries is also examined. Not only coated oxides but also bare sulfi des are found to be applicable as positive electrode active materials. Results related to fast Na-ionic conductivity in the complex hydrides are presented. In the last section, the future prospects for battery assemblies with high-energy densities, and Mg ion batteries with the liquid and the solid-state electrolytes are discussed. Figure 1. Crystal structures of a) LT phase and b) HT phase of LiBH 4 . [ 16 ]Adv. FEATURE ARTICLEto fast Li-ionic conduction, the advantages of the use of complex hydrides as rechargeable battery electrolytes are as follows, iii) Fast Li-and Na-ionic conductions: One of the important challenges in the fi eld of battery research is the development of fast ionic conductors because this class of materials enables the assembly from micro- [ 24 ] to bulk-type [25][26][27] all-solid-state rechargeable cells, which allows the broader applications. With this background, various solid-state electrolytes have been developed so far, however, the materials showing suffi cient ionic conductivity as well as good stability in the voltage ranges for battery operation are limited to a few cases. [ 28 ] Therefore, novel solid-state electrolytes are urgently required for the development of future generation batteries. Since the discovery of fast Li-ionic conduction in the HT phase of LiBH 4 , [ 29 ] we have developed numerous solid-state electrolytes based on the complex hydrides that exhibit fast Li-and Na-ionic conductions. [ 30 ] Herein, we briefl y report recent progress in the development of the complex hydrides that exhibit fast Li-ionic conduction. All-solid-state Li rechargeable batteries were subsequently assembled using coated-LiCoO 2 and TiS 2 positive electrodes, and LiBH 4 -based electrolytes. The validity of the use of the complex hydrides as electrolytes in a rechargeable battery was examined on the basis of charge-discharge measurements. In the following section, our recent development of fast Na-ionic conductors based on the complex hydrides is summarized. We discuss the future prospects for the development of high energy density rechargeable batteries, and Mg-ion batteries that use nonaqueous and solid-state electrolytes based on the complex hydrides. FEATURE ARTICLEhexagonal phase of LiBH 4 (fast Li-ion conduction phase) even at room temperature when x exceeds 0.25. And then, the solid-solution, Li 4 (BH 4 ) 3 I, exhibits fast Li-ionic conductivity of 2 × 10 −5 S cm −1 at 300 K. [ 34,[51][52][53] This phenomenon might be due to increased neighboring distance of [BH 4 ] − [ 54 ] and induced lattice anharmonicity by the partial substitution of I − instead of ...

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Native Defect Concentrations in NaAlH₄ and Na₃AlH₆

Cited by 26 publications

References 55 publications

Kinetically-Driven Phase Transformation during Lithiation in Copper Sulfide Nanoflakes

Kinetically-Driven Phase Transformation during Lithiation in Copper Sulfide Nanoflakes

Computation-Accelerated Design of Materials and Interfaces for All-Solid-State Lithium-Ion Batteries

Complex Hydrides for Electrochemical Energy Storage

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