Point defects in garnet-type solid electrolyte (c-Li7La3Zr2O12) for Li-ion batteries

Kc, Santosh; Longo, Roberto C.; Xiong, Ka; Cho, Kyeongjae

doi:10.1016/j.ssi.2014.04.021

Cited by 38 publications

(19 citation statements)

References 47 publications

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“…The calculated Ef for V Li × at 24d and 96h sites in bulk are approximate to 3.6 eV (Figure 3a), which is in good agreement with the previously calculated values (3.54 eV). 46 Interestingly, we have found that there are several V Li × with significantly higher Ef at the 1(110) GB, whose maximum value (4.3 eV) is about 0.7 eV larger than that in bulk. These sites with remarkably high Ef will lead to the large barriers for Li + migrating from neighboring sites to these sites, which is one of the main reasons for the low Li + conductivity at this GB.…”

Section: Resultsmentioning

confidence: 69%

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Gao

Jalem

Tian

et al. 2021

Preprint

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For real application to the all-solid-state batteries, understanding and control of the grain boundaries (GBs) are essential. However, the in-depth insight into the atomic-scale defect stabilities and transports of ions around the GBs is still far from understood. Here, the first-principles investigation on the promising garnet Li7La3Zr2O12 solid electrolyte GBs has been carried out. Our study reveals a GB-dependent behavior for the Li-ion transport correlated to the diffusion network. Especially, the Σ3(112) tilt GB model exhibits a quite high Li-ion conductivity comparable to that in bulk, and a fast intergranular diffusion contrary to the former concepts. Moreover, the preference of the electron accumulation at the Σ3(112) GB was uncovered in terms of the lower Li interstitial formation energies. This phenomenon is further enhanced by the presence of the Schottky-like defect, leading to the increase in the electronic conductivity at GBs, which plays a key role in the Li dendrite growth.

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Section: Resultsmentioning

confidence: 69%

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Gao

Jalem

Tian

et al. 2021

Preprint

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“…For the native defects, we find a rich family of defect species, including lithium and oxygen vacancies and interstitials, which have been discussed previously, [36][37][38][39] and cation anti-sites; such as Li La , La Zr , Li Zr , and Zr Li ; which are often neglected when considering the defect chemistry of lithium-garnets. Under all conditions except extremely O-poor (reducing) conditions, cation anti-site defects are the highest concentration defect species after V Li .…”

Section: Summary and Discussionmentioning

confidence: 72%

Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li₇La₃Zr₂O₁₂

2019

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The Li-stuffed garnets LixM2M 3 O12 are promising Li-ion solid electrolytes with potential use in solid-state batteries. One strategy for optimising ionic conductivities in these materials is to tune lithium stoichiometries through aliovalent doping, which is often assumed to produce proportionate numbers of charge-compensating Li vacancies. The native defect chemistry of the Li-stuffed garnets, and their response to doping, however, are not well understood, and it is unknown to what degree a simple vacancy-compensation model is valid. Here, we report hybrid density-functional-theory calculations of a broad range of native defects in the prototypical Li-garnet Li7La3Zr2O12. We calculate equilibrium defect concentrations as a function of synthesis conditions, and model the response of these defect populations to extrinsic doping. We predict a rich defect chemistry that includes Li and O vacancies and interstitials, and significant numbers of cation-antisite defects. Under reducing conditions, O vacancies act as colour-centres by trapping electrons. We find that supervalent (donor) doping does not produce charge compensating Li vacancies under all synthesis conditions; under Li-rich / Zr-poor conditions the dominant compensating defects are LiZr antisites, and Li stoichiometries strongly deviate from those predicted by simple "vacancy compensation" models.

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“…The calculated E f for

{normalV}_{Li}^{\times}

at 24d and 96h sites in bulk are ≈3.6 eV (Figure 3a), which is in good agreement with the previously calculated values (3.54 eV). [ 51 ] Interestingly, we have found that there are several

{normalV}_{Li}^{\times}

with significantly higher E f at the Σ1(110) GB, whose maximum value (4.3 eV) is about 0.7 eV larger than that in bulk. Our previous works have proposed that negative value of E f of

{normalV}_{Li}^{\times}

can be used to represent the Li chemical potential.…”

Section: Resultsmentioning

confidence: 82%

Revealing Atomic‐Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li₇La₃Zr₂O₁₂ Solid Electrolyte

Gao

Jalem

Tian

et al. 2021

Advanced Energy Materials

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electric vehicles. [1,2] Due to the existence of weakness of the organic liquid electrolyte in the traditional Li-ion battery (e.g., flammable), all-solid-state battery (ASSB) containing an inorganic solid electrolyte is one of the most promising candidates of the next-generation battery owing to its improved safety and cycle stability. [3][4][5] Through the long-term development, a variety of high-performance solid electrolytes (SEs) has been successfully synthesized, whose ion conductivities are comparable with the traditional liquid electrolytes. [6][7][8][9] Among of them, the garnet-type Li 7 La 3 Zr 2 O 12 (LLZO) as a superior solid electrolyte has attracted great interest, [8,10,11] owing to its high conductivity (≈10 -4 S cm −1 ), wide electrochemical window (≈6 eV). [12] More promisingly, LLZO shows a good compatibility with the ultimate anode material, Li metal, to achieve an ASSB with a significantly high energy density. [13][14][15][16][17] As most of the synthesized SEs are polycrystalline, the grain boundary (GB) has an inevitable influence on their performances. [18,19] However, until now, this underlying GB effect has not been thoroughly understood yet. For example, numerous works have reported the resistance at GB related to the decrease in the ion conductivity in LLZO, [20][21][22][23] while some other studies have observed contradictory results, where the sample with small grain size has higher conductivity than that containing large-sized grains, indicating the faster ion transport at the GBs. [24][25][26] Moreover, GBs are expected to contribute to the Li dendrite growth in LLZO, [27][28][29] which leads to the short-circuiting of the cell. [24,[30][31][32][33] It is reported that the inhomogeneous depletion and low ion conductivity at the GB are responsible for the dendrite growth. [32,34] Particularly, recent works have proposed that the dendrite propagation originates from the high electronic conductivity, [30,35] which is reported to be appeared at the GB. [36,37] Fully unraveling these serious GB issues require a comprehensive understanding of the ion diffusion, defect chemistry, and electronic properties at GB. Especially, the Li-ion conductivity at the GB has been revealed using the classical simulation methods. [19,23,38,39] Especially for LLZO, this method has indicated that the GB resistance is sensitive to the GB structure and temperature. [23] Firstprinciples simulation based on the atomistic model as a powerful way can provide comprehensive results about the properties of SE. Especially for LLZO, it has been extensively used to explain the phase transition, [40] migration mechanism, [41] electrochemical window, [12] defect chemistry, [42] and the phenomena on the surface and at the interface with Li metal. [43,44] Unfortunately, as far as we For real applications of all-solid-state batteries (ASSBs) to be realized, understanding and control of the grain boundaries (GBs) are essential. However, the in-depth insight into the atomic-scale defect stabilities and transport of ions aro...

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Point defects in garnet-type solid electrolyte (c-Li7La3Zr2O12) for Li-ion batteries

Cited by 38 publications

References 47 publications

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li₇La₃Zr₂O₁₂

Revealing Atomic‐Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li₇La₃Zr₂O₁₂ Solid Electrolyte

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Point defects in garnet-type solid electrolyte (c-Li7La3Zr2O12) for Li-ion batteries

Cited by 38 publications

References 47 publications

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Revealing Atomic-Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li7La3Zr2O12

Revealing Atomic‐Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li7La3Zr2O12 Solid Electrolyte

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Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li₇La₃Zr₂O₁₂

Revealing Atomic‐Scale Ionic Stability and Transport around Grain Boundaries of Garnet Li₇La₃Zr₂O₁₂ Solid Electrolyte