Constructing stable Li-solid electrolyte interphase to achieve dendrites-free solid-state battery: A nano-interlayer/Li pre-reduction strategy

ACS Appl. Mater. Interfaces

et al. 2022

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is one of the most promising candidate solid electrolytes for high-safety solid-state batteries. However, similar to other solid electrolytes containing volatile components during high-temperature sintering, the preparation of densified LLZO with high conductivity is challenging involving the complicated gas−liquid−solid sintering mechanism. Further attention on establishing low-cost laborastory-scale preparation craft platform of LLZO ceramic is also required. This work demonstrates a "pellet on gravel" sintering strategy, which is performed in a MgO crucible and box furnace under ambient air without any special equipment or expensive consumables. In addition, the competition between lithium loss from the sintering system and internal grain densification is critically studied, whereas the influences of particle surface energy, Li-loss amount, and initial excess Li 2 O amount are uncovered. Based on the sintering behavior and mechanism, optimized craft platform for preparing dense LLZO solid electrolytes including mixing, calcination, particle tailoring and sintering is provided. Finally, exemplary Ta-doped LLZO pellets with 2 wt % La 2 Zr 2 O 7 additives sintered at 1260−1320 °C for 20 min deliver Li + conductivities of ∼9 × 10 −4 S cm −1 at 25 °C, relative densities of >96%, and a dense cross-sectional microstructure. As a practical demonstration, LLZO solid electrolyte with optimized performance is applied in both Li−Li symmetric cells and Li−S batteries. This work sheds light on the practical production of high-quality LLZO ceramics and provides inspiration for sintering ceramics containing volatile compounds.

Section: Resultssupporting

confidence: 79%

Developing Preparation Craft Platform for Solid Electrolytes Containing Volatile Components: Experimental Study of Competition between Lithium Loss and Densification in Li₇La₃Zr₂O₁₂

Huang

Tang

ACS Appl. Mater. Interfaces

et al. 2022

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“…This long-cycling performance was comparable to that conducted with coating layers in published works. 57,58 These results demonstrated the excellent performance of asoptimized Ta-LLZO product pellets. The product ceramics were also fabricated into Li−S batteries, and the typical Nyquist plot was shown in Figure 11d.…”

Section: Electrochemical Performance Verification Of Ta5li6mentioning

confidence: 68%

Production of Ta-Doped Li₇La₃Zr₂O₁₂ Solid Electrolyte with High Critical Current Density

ACS Appl. Energy Mater.

Yang

et al. 2022

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Solid-state electrolytes are key materials for developing high-safety solid-state Li-ion batteries. The garnettype Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte is one of the most promising solid electrolytes due to its high conductivity and feasible preparation in ambient air. Among several dopants, Tadoped LLZO (Ta-LLZO) delivers high stability against lithium metal and high conductivity, which attracts lots of researchers. However, production of Ta-LLZO ceramics is less problematic due to the complicated gas−liquid−solid sintering mechanism. This work aims to develop an efficient method to produce Ta-LLZO solid electrolyte ceramic pellets, including providing a stacking sintering method and optimizing the amount of excessive Li source, the wet milling duration, and the sintering temperature. First, a low-cost, efficient "gravel-separator" strategy is provided for multiple sintering of LLZO. Second, the Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (Ta5) samples with different excessive Li levels (2, 4, 6, and 8%) are sintered at various sintering conditions of 1240 °C for 60 min, 1280 °C for 20 min, and 1320 °C for 2 min to search for the optimum excessive amount of Li. Third, Ta5 samples with optimized excessive Li (4, 6%) after milling for longer duration are sintered at 1280 °C for 30 min, 1300 °C for 10 min, 1320 °C for 10 min, 1320 °C for 30 min to finally optimize the preparation craft. After optimization, the Ta5 ceramics with excessive 4 and 6% Li sintered at 1320 °C for 10 min deliver homogeneous and dense crosssectional morphology, high conductivity of over 1 × 10 −3 S cm −1 at room temperature, and relative densities of above 96%. Furthermore, symmetric Li cells assembled with the Ta-LLZO solid electrolyte prepared with the optimized method deliver a critical current density of 1.28 mA cm −2 at 30 °C and over 1000 h of stable cycling at 0.2 mA cm −2 (0.2 mA h cm −2 ) at 30 °C.

“…Despite the overwhelming demand for lithium-ion batteries (LIBs) from booming electronic devices, electrical vehicles, etc., − the capacity of LIBs is still limited by the specific capacity (372 mAh g –1 ) of traditional anode materials, such as graphite. − While Si has a high theoretical specific capacity of 4200 mAh g –1 and a practical capacity of 3580 mAh g –1 and is believed to be one of the most promising anode materials, the brittle fracture that resulted from the huge volume variation (>300%) in delithiation/lithiation cycles blocks it from use in wide applications. − The huge volume expansion comes from the chemical reaction between Si and Li that produces the Si–Li compound. One way to defuse it is to compromise the capacity by replacing Si with SiO.…”

Section: Introductionmentioning

confidence: 99%

Preset Lithium Source Electrolyte Boosts SiO Anode Performance for Lithium-Ion Batteries

ACS Sustainable Chem. Eng.

Cheng

et al. 2022

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SiO is a promising alternative to Si as the anode material for lithium-ion batteries, but it still suffers from a low initial coulomb efficiency, poor electrical conductivity, unstable cycling performance, etc. Various strategies have been attempted to solve these issues but were left unsolved. In this work, we propose a simple strategy that checks all of the right boxes by presetting a lithium source electrolyte (Li2CO3) into a SiO film using the magnetron sputtering method. The preset lithium source electrolyte provides both the lithium ions and the electrolyte required for the formation of a solid electrolyte interphase and thus significantly improves the initial coulomb efficiency. The lithium source electrolyte also acts as a medium to facilitate the growth of a solid electrolyte interphase inside this composite film in addition to its surfaces. The interior interphase provides an efficient and fast pathway for lithium-ion transmission during the lithiation process and thus improves the anode conductivity and the rate performance. The interior interphase also suppresses the brittle fracture by buffering the dramatic volume change during the lithiation/delithiation process and stabilizes the cycling performance substantially. In addition, this strategy is safe, green, and of low-cost, when compared to others, and provides a feasible way to commercialize the SiO anode for lithium-ion batteries.