Bonding Lithium Metal with Garnet Electrolyte by Interfacial Lithiophobicity/Lithiophilicity Transition Mechanism over 380 °C

Abstract

Garnet electrolytes, possessing high ionic conductivity (10−4–10−3 S cm−1 at room temperature) and excellent chemical/electrochemical compatibility with lithium metal, are expected to be used in solid‐state lithium metal batteries. However, the poor solid–solid interfacial contact between lithium and garnet leads to high interfacial resistance, reducing the battery power capability and cyclability. Garnet electrolytes are commonly believed to be intrinsically lithiophilic, and lithiophobic Li2CO3 on the garnet surface accounted for the poor interfacial contact. Here, it is proposed that the interfacial lithiophobicity/lithiophilicity of garnets (LLZO, LLZTO) can be transformed above a temperature of ≈380 °C. This transition mechanism is also suitable for other materials such as Li2CO3, Li2O, stainless steel, and Al2O3. By using this transition mechanism, uniform and even lithium can be strongly bonded no‐surface‐treated garnet electrolytes with various shapes. The Li–LLZTO interfacial resistance can be reduced to ≈3.6 Ω cm2 and sustainably withstood lithium extraction and insertion for up to 2000 h at 100 µA cm−2. This high‐temperature lithiophobicity/lithiophilicity transition mechanism can help improve the understanding of lithium–garnet interfaces and build practical lithium–garnet solid–solid interfaces.

Nanotrench Superfilling Facilitates Embedded Lithium Anode for High-Areal-Capacity Solid-State Batteries

“…Figure d demonstrates stable cycling over 60 cycles with the Coulombic efficiency being maintained at almost 100%. Additionally, Figure e compares the current density, areal capacity, and areal loading of the NA-LLZTO prepared for the full battery with those of other advanced solid-state batteries. ,,,,− The designed Li/NA-LLZTO/LFP full battery shows prominent advantages in terms of practical application (detailed information is provided in Table S1). As shown in Figure S18, the battery exhibits clear charge–discharge profiles and maintains lower voltage polarizations.…”

Recent Progress on Nanomodification Applied in Anodes of Rechargeable Li Metal Batteries

“…Garnet-type solid electrolytes have gained significant attention in recent years due to their stability. They exhibit good chemical compatibility with lithium metal and possess high ionic conductivity, which leads to enhanced safety and energy density in lithium ion batteries. , To address the issue of dendrite growth, lithium garnet (Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , LLZTO) particles and lithium salt-free poly­(ethylene oxide) (PEO) were used to create a composite film by Zhang et al Remarkably, this solid electrolyte film demonstrated no dendrite growth even after 700 h of cycling. The nanoscale lithium ion conducting particles effectively improved electrical conductivity, while the insulating PEO in the PEO:LLZTO film electrolyte inhibited dendrite growth due to current limitations.…”

1000 °C High-Temperature Wetting Behaviors of Molten Metals on Laser-Microstructured Metal Surfaces

“…On the other hand, limited publications studied the effect of surface microstructures on the wetting behaviors of molten metals on substrates at high temperatures, while most of them concerned about the composition of the melts and the substrate surfaces or the periphery conditions. − ,,− , Lai et al found that a microporous copper substrate enhanced the wetting of molten Sn, while Zhou et al structured the steel mold surfaces to weaken the adhesion of the molten and resolidified Al alloys with the mold by preventing their full wetting. Liu et al discussed the effect of laser-textured stainless steel surface structures on the wetting and spreading behaviors of the Al–Si alloy in the presence of flux, and Lin et al observed that rough silica surfaces improved the spreading of the Sn–Ag–Ti alloy.…”

“…The melting of metals (and alloys) at high temperatures is a common phenomenon in many industrial processes, e.g., metallurgy, refining, casting, welding, and brazing. Recently, molten metals have also been proposed to be potential novel materials in various fields, such as newly developed batteries and nuclear fusion. − The wetting of molten metals on various substrate surfaces has a great impact on related processes and applications, significantly affecting the processing feasibility and product performance. However, only few literature studies focused on the wettability of molten metals at high temperatures (e.g., 1000 °C) compared with the wettability studies on more common liquids under more gentle conditions, such as water and low-melting-point liquid metals at room temperature. − Various simulations have been performed to predict the probable wetting behaviors of molten metals on various substrates, − but practical observations remain scarce due to the availability of materials and the strict environmental requirements.…”

“…However, only few literature studies focused on the wettability of molten metals at high temperatures (e.g., 1000 °C) compared with the wettability studies on more common liquids under more gentle conditions, such as water and low-melting-point liquid metals at room temperature. − Various simulations have been performed to predict the probable wetting behaviors of molten metals on various substrates, − but practical observations remain scarce due to the availability of materials and the strict environmental requirements. Among the restricted experimental work, researchers prefer to improve the wettability of molten metals with several kinds of solid surfaces for better performance in welding, brazing, metal-based composite formation, and lithium battery preparation. − ,− For example, Wu et al proposed a method to enhance the wettability of a kind of room-temperature gallium-based liquid metal on polyacrylate surfaces for a better connection, Fan et al modified the wetting and spreading behaviors of Sn on the SiC surface by changing the content of the alloying element Cr, Li et al enhanced the wettability of molten high manganese steel with Ni–Co-coated ZTA ceramic particles to strengthen the abrasive wear resistance of the composites, and Sui et al studied the wetting ability of molten Ce and Cu–Ce alloy on various carbon materials. Liu et al introduced ultrasonic power to improve the wetting of the Zn filler on the TC4 alloy and further strengthen the mechanical properties of the brazed joint, and Griffith et al investigated the effect of droplet size on the wetting behaviors of molten Sn on copper substrates for better performance of microsolder joints.…”