Li/Garnet Interface Stabilization by Thermal‐Decomposition Vapor Deposition of an Amorphous Carbon Layer

liquid electrolytes. ASSLBs exhibit overwhelming advantages as follows: 1) No electrolyte leakage. The most obvious advantage of ASSLBs is the avoidance of electrolyte leakage, and related issues such as fire hazard, electrical short circuit and corruption. In addition, ASSLBs do not need advance sealants, pressurizing electrolyte, and flame retardant failsafe. [1,2] 2) No thermal runaway. Thermal runaway will cause the rise of internal temperature, pressure, and vent of flammable gases in conventional LIBs, at a risk of explosion and shrapnel. [3,4] ASSLBs avoid the use of organic electrolytes and prevent the thermal runaway for a large extent. [5] 3) High resistance to lithium dendrite. The lithium dendrite may form during deposition process and penetrate through the separator, potentially cause a short circuit in conventional LIBs. [6] ASSLBs using solid electrolytes (SEs) with high shear modulus are expected to prevent/alleviate the dendrite penetration and extend the cell life. 4) Higher energy density. [7] The conventional LIBs are not suitable for the application of high voltage cathode and lithium metal anode because of narrow electrochemical window of liquid electrolytes, as well as failure in preventing lithium dendrite. ASSLBs facilitate the application of high voltage cathode materials and high energy density lithium metal anode, therefore increasing the energy density of the whole cell. Figure 1 shows the scheme of a typical ASSLB. Similar with conventional LIBs, the main components of ASSLB are cathode, SE, and anode. The distinctive component is SE, and its properties support the great advantages of ASSLBs. These properties include stability at ultrahigh and ultralow temperature, high mechanical strength, [8] wider electrochemical window (with passivation), and so on. [9-11] According to the category of SE, ASSLBs are divided into polymer-based, oxide-based, and sulfide-based systems, corresponding to the polymer, oxide, and sulfide electrolytes, respectively. Therein, oxide electrolytes exhibit moderate ionic conductivity, high shear modulus, and better stability with atmosphere and electrodes, are promising candidates for ASSLB. Specifically, oxide electrolytes are classified into LISICON (Li 14 ZnGe 4 O 16), NASICION (LiTi 2 (PO 4) 3), perovskite (Li 3x La 0.67-x □ 0.33-2x TiO 3), garnet (Li 3-7 LnMO 12 , Ln = Y, Pr, Nd, La, Sm-Lu, M = Zr, Sb, W, etc.), and so on based on their structure. Without reductive Ge, Ti elements in the composition, garnets are normally considered most promising among oxide electrolytes. [12,13] Garnet-type electrolytes in the formula of Li 3-7 Ln 3 M 2 O 12 , show a space group 3 Ia d. Lithium content ranges from 3 to 7 based on the substitution elements at Ln and M sites. [14,15] All-solid-state lithium batteries (ASSLBs) are considered to be the nextgeneration energy storage system, because of their overwhelming advantages in energy density and safety compared to conventional lithium ion batteries. Among various systems, garnet-based ASSLBs are one of the most promis...

Section: Artificial Interlayermentioning

confidence: 99%

Interfaces in Garnet‐Based All‐Solid‐State Lithium Batteries

Wang

Zhu

et al. 2020

“…[ 30 ] Aided by these recent advancements, the CCD has been reported to reach ≈1 mA cm –2 . [ 31–34 ] Despite the significant efforts laid toward understanding and mitigating the growth of filaments in LLZO, to date, its electro‐chemo‐mechanical origin is yet to be revealed. In fact, a number of studies have shown that electro‐chemo‐mechanical coupling strongly affects the interfacial stability of solid‐state batteries (SSBs).…”

Section: Introductionmentioning

confidence: 99%

Modulating Nanoinhomogeneity at Electrode–Solid Electrolyte Interfaces for Dendrite‐Proof Solid‐State Batteries and Long‐Life Memristors

Yang

et al. 2021

Dendrite penetration in ceramic lithium conductors severely constrains the development of solid‐state batteries (SSBs) while its nanoscale origin remains unelucidated. An in situ nanoscopic electrochemical characterization technique is developed based on conductive‐atomic force microscopy (c‐AFM) to reveal the local dendrite growth kinetics. Using Li7La3Zr2O12 (LLZO) as a model system, significant local inhomogeneity is observed with a hundredfold decrease in the dendrite triggering bias at grain boundaries compared with that at grain interiors. The origin of the local weakening is assigned to the nanoscale variation of elastic modulus and lithium flux detouring. An ionic‐conductive polymeric homogenizing layer is designed which achieves a high critical current density of 1.8 mA cm–2 and a low interfacial resistance of 14 Ω cm2. Practical SSBs based on LiFePO4 cathodes can be stably cycled over 300 times. Beyond this, highly reversible electrochemical dendrite healing in LLZO is discovered using the c‐AFM electrode, based on which a model memristor with a high on/off ratio of ≈105 is demonstrated for >200 cycles. This work not only provides a novel tool to investigate and design interfaces in SSBs but also offers opportunities for solid electrolytes beyond energy applications.

Section: The Strategies To Suppress Lithium Dendritementioning

confidence: 99%

Dendrites in Solid‐State Batteries: Ion Transport Behavior, Advanced Characterization, and Interface Regulation

Zhang

et al. 2021

Solid‐state electrolytes (SSEs) are attracting growing interest for next‐generation Li‐metal batteries with theoretically high energy density, but they currently suffer from safety concerns caused by dendrite growth, hindering their commercial applications. Interfaces between SSEs and solid lithium are argued to be crucial, affecting dendrite growth and determining solid‐state batteries (SSBs) performance. The buried and localized nature of the interface poses a huge challenge for direct characterization under working conditions. Recent review articles have been devoted to evaluating the conductivity and chemical stability of SSEs. Recognizing this, in this Review, the focus is on understanding lithium dendrite beyond conventional factors and offering a perspective on various surface/interface and microstructural phenomena that require close attention by both experimentalists and theoreticians. The complicated ion‐transport mechanism and chemomechanical information correlated with interface and lithium dendrite are discussed. Rational solutions are provided to engineer functional interfaces to suppress lithium dendrites and accelerate progress towards the commercialization of SSBs.