Low-sintering-temperature garnet oxides by conformal sintering-aid coating

Chen, Shaojie; Hu, Xiangchen; Bao, Wenda; Wang, Zeyu; Yang, Qun; Nie, Lu; Zhang, Xun; Zhang, Jingxuan; Jiang, Yilan; Han, Yi; Wan, Chunlei; Xie, Jin; Yu, Yi; Liu, Wei

doi:10.1016/j.xcrp.2021.100569

Cited by 36 publications

(18 citation statements)

References 75 publications

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“…However, the lithium dendrite growth inside pure LLZTO persists due to the Li deposition along grain boundaries, although the desirable Li-ion conductivity is obtained via the Ta doping strategy. − The homogeneity of Ta distribution in pure LLZTO is usually neglected. Ta-rich and Ta-poor zones are found to coexist within the matrix of LLZTO grains, while the Ta-rich zone appears along the grain boundaries around the void defects. , Critical current density (CCD) of symmetric cells with SSEs is normally less than 2 mA cm –2 at room temperature. , Long-term cycling performance is severely hampered owing to the lithium dendrite growth. , The lithium dendrite formation is attributed to the high electronic conductivity and low ionic conductivity around the void defects at the grain boundaries. − The electrons reduce Li ions to form metallic Li (Li + to Li 0 ), resulting in local short-circuit phenomena. , The mechanism of short-circuit in garnet SSEs is different from that in liquid electrolytes, where lithium dendrites first nucleate at the Li/electrolyte interface, further propagate along the grain boundaries or through the voids. , Therefore, achieving the homogeneous Ta distribution and eliminating the void defects are promising strategies to suppress lithium dendrite growth. − Wen and co-workers introduced Li 6 Zr 2 O 7 particles to regulate the Li 2 O atmosphere and fill the voids along the grain boundaries during the sintering of LLZTO. The CCD was improved to 1.4 mA cm –2 at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Grain Boundary Engineering in Ta-Doped Garnet-Type Electrolyte for Lithium Dendrite Suppression

Qin

Xie

Meng

et al. 2022

ACS Appl. Mater. Interfaces

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Solid-state lithium batteries (SSLBs) based on Ta-doped Li6.5La3Zr1.5Ta0.5O12 (LLZTO) suffer from lithium dendrite growth, which hinders their practical application. Herein, first principles simulations indicate that the Ta element prefers to segregate along grain boundaries in the form of Ta2O5 precipitates due to a high energy difference induced by Ta doping. Grain boundary engineering is employed to regulate the distribution of the Ta element and enhance the density of LLZTO by introducing the La2O3 additive. The sufficient La2O3 additive reacts with the Ta2O5 precipitates, while the residual La2O3 nanoparticles fill up void defects, promoting the homogeneous distribution of the Ta element and improving the relative density to ∼98%. Critical current density of the symmetric Li battery reaches 2.12 mA·cm–2 at room temperature with the solid-state electrolyte (LLZTO + 5 wt % La2O3), which increases by 41% compared to pure LLZTO. SSLBs with the LiFePO4 cathode achieve a stable cycling performance with a discharge capacity of 138.6 mA·h·g–1 after 400 cycles at 0.2 C. This work provides theoretical insights into the distribution of Ta-doped LLZTO and inhibits lithium dendrite growth through grain boundary engineering.

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Section: Introductionmentioning

confidence: 99%

Grain Boundary Engineering in Ta-Doped Garnet-Type Electrolyte for Lithium Dendrite Suppression

Qin

Xie

Meng

et al. 2022

ACS Appl. Mater. Interfaces

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“…68,69 Such benefits of an amorphous phase (with a different chemistry compared to our work) in the grain boundaries on mechanical and electrochemical properties have been reported before, but often only relatively low CCD values of about 0.5 mA cm −2 were achieved. [38][39][40]70 The main difference to our approach is that the amorphous phase is formed by adding phases or glasses to the initial powders, which can result in inhomogeneous mixing of the powders. In our material, the amorphous phase is intrinsically incorporated in the powder due to the melting process promoting excellent distribution and outstanding dendrite stability.…”

Section: Mechanism Of Lithium Dendrite Suppressionmentioning

confidence: 99%

“…During the actual sintering step, the liquid phase already formed before tends to wet the surfaces of the ceramic grains, and as a result, it fills the grain boundaries and thus leads to improved densification. As sintering additives, mostly lithium compounds like Li 2 O, LiOH, Li 3 PO 4 , Li 3 BO 3 , , LiAlO 2 (by an uncontrolled reaction of excess Li 2 CO 3 with an Al 2 O 3 crucible or by atomic layer deposition coating of Al 2 O 3 ), and lithium-containing glass systems (e.g., Li 2 O–B 2 O 3 –SiO 2 and 3Li 2 O–2GeO 2 ) have been investigated. Even though the sintering temperature can effectively be reduced to around 1000 °C by these methods, the sintering time is still long (10 h up to 36 h − ), and, if measured, CCD values are relatively low (0.3 to 0.6 mA cm –1 ,,, ), indicating poor lithium dendrite suppression.…”

Section: Introductionmentioning

confidence: 99%

Amorphous Phase Induced Lithium Dendrite Suppression in Glass-Ceramic Garnet-Type Solid Electrolytes

Hoinkis

Schuhmacher

Fuchs

et al. 2023

ACS Appl. Mater. Interfaces

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Lithium metal-based solid-state batteries (SSBs) have attracted much attention due to their potentially higher energy densities and improved safety compared with lithium-ion batteries. One of the most promising solid electrolytes, garnet-type Li7La3Zr2O12 (LLZO), has been investigated intensively in recent years. It enables the use of a lithium metal anode, but its application is still challenging because of lithium dendrites that grow at voids, cracks, and grain boundaries of sintered bodies during cycling of the battery cell. In this work, glass-ceramic Ta-doped LLZO produced in a unique melting process was investigated. Upon cooling, an amorphous phase is generated intrinsically, whose composition and fraction are adjusted during the process. Herein, it was set to about 4 wt % containing Li2O and a Li2O–SiO2 phase. During sintering, it was shown to segregate into the grain boundaries and decrease porosity via liquid phase sintering. Sintering temperature and sintering time were found to be reduced compared with the LLZO fabricated by a solid-state reaction while maintaining high density and ionic conductivity. The glass-ceramic sintered at 1130 °C for 0.5 h showed a room-temperature ionic conductivity of 0.64 mS cm–1. Most importantly, the evenly distributed amorphous phase along the grain boundaries effectively hinders lithium dendrite growth. Besides mechanically blocking pores and voids, it helps to prevent inhomogeneous distribution of current density. The critical current density (CCD) of the Li|LLZTO|Li symmetric cell was determined as 1.15 mA cm–2, and in situ lithium plating experiments in a scanning electron microscope revealed superior dendrite stability properties. Therefore, this work provides a promising strategy to prepare a dense and dendrite-suppressing solid electrolyte for future implementation in SSBs.

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“…[14][15][16][17] However, the densification of oxide ceramic electrolyte often requires a high temperature (>1100 °C) and a long holding time (>10 h) by conventional sintering, which is very likely to result in impurities, because of the significant risk of volatilization of Li/Na during high-temperature processing. [18][19][20] In addition, a stable and sufficient interfacial contact between SEs and electrodes could not be achieved by the conventional high-temperatures co-sintering method, due to severe element interdiffusion. [21] Therefore, the methods for the rapid densification of high-quality oxide ceramic electrolytes as well as the sintering process, a preheating process (500 W, ≈80 s) and a following sintering (800 W, ≈25 s) were included.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Sintering for Ceramic‐Based All‐Solid‐State Lithium‐Metal Batteries

Chen

Nie

et al. 2022

Advanced Materials

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Long processing time and high temperatures are often required in sintering ceramic electrolytes, which lead to volatile element loss and high cost. Here, an ultrafast sintering method of microwave‐induced carbothermal shock to fabricate various ceramic electrolytes in seconds is reported. Furthermore, it is also possible to integrate the electrode and electrolyte in one step by simultaneous co‐sintering. Based on this ultrafast co‐sintering technique, an all‐solid‐state lithium‐metal battery with a high areal capacity is successfully achieved, realizing a promising electrochemical performance at room temperature. This method can extend to other various ceramic multilayer‐based solid devices.

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Low-sintering-temperature garnet oxides by conformal sintering-aid coating

Cited by 36 publications

References 75 publications

Grain Boundary Engineering in Ta-Doped Garnet-Type Electrolyte for Lithium Dendrite Suppression

Grain Boundary Engineering in Ta-Doped Garnet-Type Electrolyte for Lithium Dendrite Suppression

Amorphous Phase Induced Lithium Dendrite Suppression in Glass-Ceramic Garnet-Type Solid Electrolytes

Ultrafast Sintering for Ceramic‐Based All‐Solid‐State Lithium‐Metal Batteries

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