Sintering behavior and electrochemical properties of garnet-like lithium conductor Li6.25M0.25La3Zr2O12 (M: Al3+ and Ga3+)

Matsuda, Yasuaki; Sakaida, Asami; Sugimoto, Kaoru; Mori, Daisuke; Takeda, Yasuo; Yamamoto, Osamu

doi:10.1016/j.ssi.2017.09.014

Cited by 51 publications

(65 citation statements)

References 30 publications

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“…Figure 13c shows the ionic conductivity observed for various Sr composition of x = 0.0-0.5 [50]. Similar results were reported by other groups [52,76,[165][166][167]. It was else reported that the thickness of the pellet might affect the value of conductivity, causing the ionic conductivity to vary for the samples which are even the same in composition and crystal structure [36,168].…”

Section: Doping and LI Ionic Conductivitysupporting

confidence: 83%

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

et al. 2021

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As an essential part of solid-state lithium-ion batteries, solid electrolytes are receiving increasing interest. Among all solid electrolytes, garnet-type Li7La3Zr2O12 (LLZO) has proven to be one of the most promising electrolytes because of its high ionic conductivity at room temperature, low activation energy, good chemical and electrochemical stability, and wide potential window. Since the first report of LLZO, extensive research has been done in both experimental investigations and theoretical simulations aiming to improve its performance and make LLZO a feasible solid electrolyte. These include developing different methods for the synthesis of LLZO, using different crucibles and different sintering temperatures to stabilize the crystal structure, and adopting different methods of cation doping to achieve more stable LLZO with a higher ionic conductivity and lower activation energy. It also includes intensive efforts made to reveal the mechanism of Li ion movement and understand its determination of the ionic conductivity of the material through molecular dynamic simulations. Nonetheless, more insightful study is expected in order to obtain LLZO with a higher ionic conductivity at room temperature and further improve chemical and electrochemical stability, while optimal multiple doping is thought to be a feasible and promising route. This review summarizes recent progress in the investigations of crystal structure and preparation of LLZO, and the impacts of doping on the lithium ionic conductivity of LLZO.

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Section: Doping and LI Ionic Conductivitysupporting

confidence: 83%

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

et al. 2021

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“…Sample density: Higher garnet pellet relative densities tend to increase the conductivity. Matsuda et al 59 used impedance spectroscopy to show that decreasing the density 21 are represented by filled symbols (error bars smaller than symbols). Literature data from experiments by Rettenwander et al, 11 Bernuy-Lopez et al, 16 Wu et al, 49 Wachter-Welzl et al, 69 Suzuki et al, 70 Zhang et al, 61 Rangasamy et al, 60 Matsuda et al 59 and Yi et al 63 (0.8 mS/cm), and Bernuy-Lopez et al 16 (1.0 mS/cm).…”

Section: Li-ion Conductivity In Bulk Structurementioning

confidence: 99%

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li₇La₃Zr₂O₁₂ Solid Electrolytes

Daza

Bonilla

Llordés

et al. 2018

ACS Appl. Mater. Interfaces

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is a promising solid electrolyte for next-generation solid-state Li batteries. However, sufficiently fast Li-ion mobility required for battery applications only emerges at high temperatures, upon a phase transition to cubic structure. A well-known strategy to stabilize the cubic phase at room temperature relies on aliovalent substitution; in particular, the substitution of Li + by Al 3+ and Ga 3+ ions. Yet, despite having the same formal charge, Ga 3+ substitution yields higher conductivities (10 −3 S/cm) than Al 3+ (10 −4 S/cm). The reason of such difference in ionic conductivity remains a mystery. Here we use molecular dynamic simulations and advanced sampling techniques to precisely unveil the atomistic origin of this phenomenon. Our results show that Li + vacancies generated by Al 3+ and Ga 3+ substitution remain adjacent to Ga 3+ and Al 3+ ions, without contributing to the promotion of Li + mobility. However, while Ga 3+ ions tend to allow limited Li + diffusion within their immediate surroundings, the less repulsive interactions associated with Al 3+ ions lead to a complete blockage of neighboring Li + diffusion paths. This effect is magnified at lower temperatures, and explains the higher conductivities observed for Ga-substituted systems. Overall this study provides a valuable insight into the fundamental ion transport mechanism in the bulk of Ga/Al-substituted Li 7 La 3 Zr 2 O 12 and paves the way for rationalizing aliovalent substitution design strategies for enhancing ionic transport in these materials.

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“…Many dopants have been attempted, for example, Al and Ga at the Li site; Y and Sr at the La site; and Ta , and Nb at the Zr site. Among them, the Al- and Ga-stabilized LLZO have been studied intensively because of their high ionic conductivity and good sinter ability. − Al is the first dopant found to be effective to stabilize the cubic phase as a result of unintentional contamination from the crucible during sintering. , It enters the Li sites along with the two Li vacancies formed according to the following crystal-chemistry reaction (eq ) …”

Section: Introductionmentioning

confidence: 99%

Microstructural and Electrochemical Properties of Al- and Ga-Doped Li₇La₃Zr₂O₁₂ Garnet Solid Electrolytes

Chen

Sun

et al. 2020

ACS Appl. Energy Mater.

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The Garnet-type solid electrolyte Li 7 La 3 Zr 2 O 12 (LLZO) showing high ionic conductivity and a wide electrochemical potential window is considered as one of the most promising candidates for solid-state batteries. Among various doping derivatives, the Al-and Ga-doped LLZO electrolytes are intensively studied because of their ability to enhance the stability of the cubic structure and to promote good sinter ability as well. Despite showing great similarities in site preference and sintering behavior, the Al and Ga doping derivatives differ by 1 order of magnitude in total ionic conductivity. Therefore, a comparative study on the doping characteristics of Al and Ga with respect to ionic conductivity and sintering behavior is necessary. Herein, we simultaneously introduced Al and Ga into Li sites (Al x Ga 0.25−x -LLZO) to study their influences on the microstructure and electrochemical properties of LLZO. The results show that Ga doping enables a higher conductivity than Al doping and largely promotes sinter ability at the same time. Compared to Al single doping (Al 0.25 ), Ga-contained compositions (x < 0.25) show significant grain growth. Moreover, a slight inclusion of Ga (Al 0.20 Ga 0.05 ) not only modifies the sintering behavior that results in a microstructure transition from fine grains of Al 0.25 (5−20 μm) to abnormally large grains (several hundred micrometers) but also greatly enhances the conductivity, yielding a value that is 3 times higher. However, further increases in Ga ratio in Al x Ga 0.25−x results in marginal increases in conductivity. The total conductivity reaches a maximum of 1.19 × 10 −3 S cm −1 for Ga single doping (Ga 0.25 ) at room temperature. In addition, Al 0.25 also shows fast ion conducting behavior along the grain boundaries with a conductivity of 8.30 × 10 −4 S cm −1 . Consequently, this study sheds lights on the different doping characteristics between Al and Ga, providing guidance for fine composition engineering of these two promising dopants.

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Sintering behavior and electrochemical properties of garnet-like lithium conductor Li6.25M0.25La3Zr2O12 (M: Al3+ and Ga3+)

Cited by 51 publications

References 30 publications

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li₇La₃Zr₂O₁₂ Solid Electrolytes

Microstructural and Electrochemical Properties of Al- and Ga-Doped Li₇La₃Zr₂O₁₂ Garnet Solid Electrolytes

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Sintering behavior and electrochemical properties of garnet-like lithium conductor Li6.25M0.25La3Zr2O12 (M: Al3+ and Ga3+)

Cited by 51 publications

References 30 publications

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

Crystal Structure and Preparation of Li7La3Zr2O12 (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li7La3Zr2O12 Solid Electrolytes

Microstructural and Electrochemical Properties of Al- and Ga-Doped Li7La3Zr2O12 Garnet Solid Electrolytes

Contact Info

Product

Resources

About

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li₇La₃Zr₂O₁₂ Solid Electrolytes

Microstructural and Electrochemical Properties of Al- and Ga-Doped Li₇La₃Zr₂O₁₂ Garnet Solid Electrolytes