Influence of sintering additives on densification and Li+ conductivity of Al doped Li7La3Zr2O12 lithium garnet

Janani, N.; Deviannapoorani, C.; Dhivya, L.; Murugan, Ramaswamy

doi:10.1039/c4ra08674k

Cited by 134 publications

(91 citation statements)

References 31 publications

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“…More recently, additives of sintering as LiBO 2 , Li 3 BO 3 , Li 3 PO 4 , and Li 4 SiO 4 have shown positive effects for reducing the sintering temperature and maintaining high conductivity [14,[17][18][19]. Tadanaga and a coworker reported Li-ion conductivity of 1 × 10 −4 S cm −1 at 30°C using Li 3 BO 3 as an additive to pristine LLZO-Al, prepared at the lower sintering temperature of 900°C [14].…”

Section: Introductionmentioning

confidence: 95%

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Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

et al. 2016

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Section: Introductionmentioning

confidence: 95%

“…The adequate concentration of the additive is a key parameter. The Li-ion conductivity in the garnet electrolyte showed variation of more than one order of magnitude as a function of the additive concentration [17,19].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

et al. 2016

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“…18,32 The peak at ∼750 cm −1 could be due to the stretching modes of TaO 6 octahedra. 33 Electrical conductivity.-Typical AC impedance spectra of Li 6 La 3 Ta 1.5 Y 0.5 O 12 prepared using 2.5 to 15 wt.…”

Section: CMmentioning

confidence: 99%

“…11 Attempts have also been made to reduce the sintering temperature and improve the control of stoichiometry via wet chemical synthesis as well as through additives acting as sintering aids. [12][13][14][15][16][17][18] It has been shown that Al migrates from the alumina crucible used for garnet synthesis, causing significant effects in the material including stabilization of the cubic phase. [15][16][17][18] Lithium salts such as Li 2 20 They also found that the glassy-like phase formed at the grain-boundaries increases the density of material as well as helps to decrease the grain-boundary and improve the total Li + conductivity.…”

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confidence: 99%

Effect of Excess Li on the Structural and Electrical Properties of Garnet-Type Li₆La₃Ta_1.5Y_0.5O₁₂

Narayanan

Hitz

Wachsman

et al. 2015

J. Electrochem. Soc.

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Volatility of lithium during preparation of lithium-stuffed garnet-type metal oxide solid Li ion electrolytes is a common problem, which affects phase formation, ionic conductivity, mechanical strength and density. Synthesis of Li-stuffed garnets has been performed generally using the conventional solid-state reactions at elevated temperature in air. The present study describes the effect of excess LiNO 3 (2.5 to 15 wt.%) addition during the ceramic synthesis on the structural and electrical properties of garnet-type Li 6 La 3 Ta 1.5 Y 0.5 O 12 . Powder X-ray diffraction (PXRD) confirmed that cubic phase was formed in all tested cases, and there is no significant variation in lattice parameter with amount of excess LiNO 3 used. However, increasing amounts of excess lithium decreased inter-particle contact and increased grain growth during sintering, producing sharply varied microstructures. PXRD showed no secondary phase and scanning electron microscopy (SEM) analysis showed rather uniform morphology and absence of "glassy" materials at the grain-boundaries. The bulk Li ion conductivity was found to increase with amount of excess lithium, reaching a maximum room temperature conductivity of 1.62 × 10 −4 Scm −1 for the sample prepared using 10 wt.% excess LiNO 3 . Raman microscopy study indicated the presence of Li 2 CO 3 in all aged Li 6 La 3 Ta Li-stuffed garnet-type metal oxides have been considered as a potential candidate solid electrolyte material to replace conventional organic liquid based Li ion conducting electrolytes in Li-ion batteries, since members of garnet solid electrolytes exhibit high bulk ion conductivity of 10 −4 -10 −3 Scm −1 at room temperature. Furthermore, some of the garnet-type electrolytes show excellent chemical stability against reaction with elemental Li, Li-ion insertion or intercalation cathodes and high electrochemical stability window.1,2 However, the synthesis of high bulk Li ion conducting garnet-type metal oxidebased lithium ion conductors is a challenging process, very sensitive to preparation conditions used, that are not yet fully characterized. For example, Li 7 La 3 Zr 2 O 12 calcined at 1230• C results in highly conducting (7 × 10 −4 Scm −1 at room temperature) cubic phase with a space group Ia-3d whereas a calcining temperature of 980• C leads to tetragonal phase with a space group I4 1 /acd, which showed 2 orders of magnitude less conductive than cubic phase.3,4 Traditional solid-state techniques are the most commonly used to synthesize garnet-type metal oxides, but usually require the highest sintering temperature resulting in the production of large particles. [5][6][7][8] It is known that volatilization of lithium occurs in the furnace, therefore, several researchers commonly compensate with a 10 wt.% excess lithium precursors.3,9,10 Al-doped Li 7 La 3 Zr 2 O 12 prepared without adding any excess lithium salts during synthesis, but varying the processing using powder cover condition for sintering, greatly affects the morphology, grain size and density. 11Attempts h...

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“…Li-ion conductivity of Li6.625La3Zr1.625Ta0.375O12 sintered at 1000 °C (24 h) with 29 mol% Al [12] reaches 5 × 10 -4 S/cm. Other compounds used as sintering additives include Li2O, Li3BO3, Li3PO4 and Li4SiO4 [13][14][15][16][17][18]. These materials act as binder between the garnet particles during the sintering treatment by the formation of liquid phases at low temperatures, reducing the grain boundary resistance and improving the Li-ion conductivity pathway.…”

mentioning

confidence: 99%

Optimization of Al2O3 and Li3BO3 Content as Sintering Additives of Li7−x La2.95Ca0.05ZrTaO12 at Low Temperature

Rosero-Navarro

Miura

Higuchi

et al. 2016

Journal of Elec Materi

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Simultaneous effect of Al2O3 and Li3BO3 addition on sintering behavior and Li-ion conductivity of Li7-xLa2.95Ca0.05ZrTaO12 (LLCZT) garnet electrolyte sintered at 900 °C (10 h) is evaluated. Crystal phase and microstructure of the different composites were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Electrical properties of the composites with high relative densities (95 %) were examined by impedance spectroscopy (EIS). Cubic phase was formed for LLCZT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

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Influence of sintering additives on densification and Li⁺ conductivity of Al doped Li₇La₃Zr₂O₁₂ lithium garnet

Abstract: Al–LLZ with 1 wt% of Li4SiO4 added and sintered at 1200 °C was found to be relatively dense which enhances the total (bulk + grain-boundary) Li+ conductivity by reducing the grain-boundary contribution.

Cited by 134 publications

References 31 publications

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

Effect of Excess Li on the Structural and Electrical Properties of Garnet-Type Li₆La₃Ta_1.5Y_0.5O₁₂

Optimization of Al2O3 and Li3BO3 Content as Sintering Additives of Li7−x La2.95Ca0.05ZrTaO12 at Low Temperature

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Influence of sintering additives on densification and Li+ conductivity of Al doped Li7La3Zr2O12 lithium garnet

Abstract: Al–LLZ with 1 wt% of Li4SiO4 added and sintered at 1200 °C was found to be relatively dense which enhances the total (bulk + grain-boundary) Li+ conductivity by reducing the grain-boundary contribution.

Cited by 134 publications

References 31 publications

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

Preparation of Li7La3(Zr2−,Nb )O12 (x= 0–1.5) and Li3BO3/LiBO2 composites at low temperatures using a sol–gel process

Effect of Excess Li on the Structural and Electrical Properties of Garnet-Type Li6La3Ta1.5Y0.5O12

Optimization of Al2O3 and Li3BO3 Content as Sintering Additives of Li7−x La2.95Ca0.05ZrTaO12 at Low Temperature

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Influence of sintering additives on densification and Li⁺ conductivity of Al doped Li₇La₃Zr₂O₁₂ lithium garnet

Effect of Excess Li on the Structural and Electrical Properties of Garnet-Type Li₆La₃Ta_1.5Y_0.5O₁₂