Characterization of grain-boundary phases in Li7La3Zr2O12 solid electrolytes

Kim, Ki‐Hyun; Hirayama, Tsukasa; Fisher, Craig A. J.; Yamamoto, Kazuo; Sato, Taketomo; Tanabe, Kinuka; Kumazaki, Shota; Iriyama, Yasutoshi; Ogumi, Zempachi

doi:10.1016/j.matchar.2014.01.031

Cited by 19 publications

(11 citation statements)

References 16 publications

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“…A molten glassy Li−Al-rich phase that decorates between most of the grains can also be clearly seen, as indexed by red dashed circles, and is the residual material from the using of excess 20 mol % LiOH and intentionally added 2.5 mol % Al 2 O 3 . This Li−Al glassy phase is often found in Alcontaminated LLZ and is believed to serve as a sintering additive that helps the densification of the pellets during the sintering process, as reported by Kotobuki et al and Kim et al 17,18 During the sintering process of LLZ:Ta, an alumina crucible and lid were used. The lid was usually sealed to the crucible by lithium alumina, which is the product of Li vapor and the alumina crucible at high temperature and keeps the lithium partial pressure inside the crucible constant.…”

Section: ■ Results and Discussionmentioning

confidence: 93%

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention

Tsai

Roddatis

Chandran

et al. 2016

ACS Appl. Mater. Interfaces

659

620

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Al-contaminated Ta-substituted Li7La3Zr2O12 (LLZ:Ta), synthesized via solid-state reaction, and Al-free Ta-substituted Li7La3Zr2O12, fabricated by hot-press sintering (HP-LLZ:Ta), have relative densities of 92.7% and 99.0%, respectively. Impedance spectra show the total conductivity of LLZ:Ta to be 0.71 mS cm(-1) at 30 °C and that of HP-LLZ:Ta to be 1.18 mS cm(-1). The lower total conductivity for LLZ:Ta than HP-LLZ:Ta was attributed to the higher grain boundary resistance and lower relative density of LLZ:Ta, as confirmed by their microstructures. Constant direct current measurements of HP-LLZ:Ta with a current density of 0.5 mA cm(-2) suggest that the short circuit formation was neither due to the low relative density of the samples nor the reduction of Li-Al glassy phase at grain boundaries. TEM, EELS, and MAS NMR were used to prove that the short circuit was from Li dendrite formation inside HP-LLZ:Ta, which took place along the grain boundaries. The Li dendrite formation was found to be mostly due to the inhomogeneous contact between LLZ solid electrolyte and Li electrodes. By flatting the surface of the LLZ:Ta pellets and using thin layers of Au buffer to improve the contact between LLZ:Ta and Li electrodes, the interface resistance could be dramatically reduced, which results in short-circuit-free cells when running a current density of 0.5 mA cm(-2) through the pellets. Temperature-dependent stepped current density galvanostatic cyclings were also carried out to determine the critical current densities for the short circuit formation. The short circuit that still occurred at higher current density is due to the inhomogeneous dissolution and deposition of metallic Li at the interfaces of Li electrodes and LLZ solid electrolyte when cycling the cell at large current densities.

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Section: ■ Results and Discussionmentioning

confidence: 93%

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention

Tsai

Roddatis

Chandran

et al. 2016

ACS Appl. Mater. Interfaces

659

620

View full text Add to dashboard Cite

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“…According to early studies, it is believed that the observed impurity is a polymorph of Li–Al–O phases. [ 52,53 ] Considering that no Al‐containing reagent was intentionally added to the starting materials, here, Al is supposed to all come from the alumina crucible used for sintering.…”

Section: Resultsmentioning

confidence: 99%

“…[ 61,62 ] In conventional liquid electrolytes, the high fluidity and fast ion mobility guarantee a uniform ion supply. Whilst in solid electrolytes, the spatial distribution of Li ion flux is widespread [ 52,63,64 ] (especially for the SEs with a large number of intrinsic defects), and its influence has been largely ignored in the past. We believe that the spatial ion flux inside SEs can directly work on the nucleation and growth.…”

Section: Discussionmentioning

confidence: 99%

Linking the Defects to the Formation and Growth of Li Dendrite in All‐Solid‐State Batteries

Wang

Gao

Chen

et al. 2021

Advanced Energy Materials

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The nucleation and growth of Li metal during deposition and the associated dendrite penetration are the critical and fundamental issues influencing the safety and power density of solid‐state lithium metal batteries (SSLBs). However, investigations on Li metal deposition/dissolution especially the formation and growth of Li dendrites and their determining factors in the all‐solid‐state electrochemical systems are still lacking. In this work, in situ observations of the Li metal growth process, and defects induced heterogeneous deposition under cathodic load, are reported. By exploiting in situ scanning electron microscopy, along with electrochemical analytical approaches, the spatial distribution and morphological evolution of the deposited Li at the electrode|solid electrolyte interface are obtained and discussed. This investigation reveals that the formation of lithium whiskers is decided by the local Li ion flux and the deposition active sites, which are closely dependent on the content and types of defects in the polycrystalline electrolyte. Moreover, the defect regions exhibit faster Li deposition kinetics and higher nucleation tendency. These results can advance the fundamental understanding of the Li penetration mechanism in SSLBs.

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“…These results are in full agreement with those reported by [32] who performed the EDX analysis for potassium doped lithium zirconate and confirmed the presence of potassium over the surface of the sample and lithium can't be determined. K.H.Kim et al [33] characterized Al-doped Li7La3Zr2O12 by using EDX elemental mapping and it revealed that Al-accumulate at the grain-boundary regions.…”

Section: Micro-structuralmentioning

confidence: 99%

Narrow Range of Al3+-doping on Li2-xAlxZrO3 (Al-LZO) for Enhancing Dual Capture Capability of CO2/NH3

2023

JCBSC

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In the present investigations, low concentrations of Al 3+ -doping were applied to insert on the Li-sites of lithium zirconate (LZO) system. Samples with general formula Li2-xAlxZrO3 were carefully synthesized via advanced solid state reaction route (where x = 0.0, 0.025, 0.075 and 0.1 mol respectively) at sintering temperature of 860 ο C coupled with slow rate of annealing 3 ο /min. The variant synthesized Al-doped LZO-samples were carefully characterized via numerous analytical tools as solid infrared absorption spectra IR and thermal analyses (TGA&DTA) which carried out on green mixture. X-ray diffraction analyses indicated that, all Al-doped LZO-samples are mainly belonging to monoclinic crystal form with C12/C1space group. Microstructural features, as grain sizes and texture nature were examined via both of scanning electron microscopy (SEM), and 3D-atomic force microscope (3D-AFM). Additionally BET-specific surface area for synthesized Al-doped samples were calculated and found to be promising and ranged in between 1.18-1.21 m 2 g -1 . Furthermore, parent and variant Al-doped samples exhibited moderate to strong efficiency as acid/base gas trapper for CO2/NH3.

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Characterization of grain-boundary phases in Li7La3Zr2O12 solid electrolytes

Cited by 19 publications

References 16 publications

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention

Linking the Defects to the Formation and Growth of Li Dendrite in All‐Solid‐State Batteries

Narrow Range of Al3+-doping on Li2-xAlxZrO3 (Al-LZO) for Enhancing Dual Capture Capability of CO2/NH3

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Characterization of grain-boundary phases in Li7La3Zr2O12 solid electrolytes

Cited by 19 publications

References 16 publications

Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention

Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention

Linking the Defects to the Formation and Growth of Li Dendrite in All‐Solid‐State Batteries

Narrow Range of Al3+-doping on Li2-xAlxZrO3 (Al-LZO) for Enhancing Dual Capture Capability of CO2/NH3

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Product

Resources

About

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention

Li₇La₃Zr₂O₁₂ Interface Modification for Li Dendrite Prevention