Performance Of Lithium Metal Anodes Research Articles

Lithium Metal Anode in Electrochemical Perspective

AbstractLithium metal is a possible anode material for building high energy density secondary batteries, but its problems during cycling have hindered the commercialization of lithium metal secondary batteries. Until now, many sophisticated techniques have been used to obtain rich micro‐morphological and physicochemical information of the deposition layer and the solid electrolyte interface (SEI), and to develop improvement strategies based on the information and achieve remarkable results. Regulating the reaction process around key links is a classic strategy to achieve expected results. Based on this empirical fact, we artificially highlighted the differences in the apparent performance of lithium metal anode using different series of electrolytes. We used microelectrode technology to analyze the reaction mechanisms and kinetic characteristics of each elementary step under all electrolyte conditions, revealing common laws that affect apparent performance and the basic steps that have a decisive impact on apparent performance. We discussed and elucidated the relevant physical and chemical principles, providing a clear basis for improving the pertinence and efficiency of improvement strategies.

Cycling performance of Li metal anode in localized high concentration electrolyte and dynamic mechanism analysis

In this work, we investigated the apparent cycling performance of lithium metal at different chemical compositions and series current densities; examined the microscopic morphology and thickness variation of the deposition layer on the surface of lithium metal anode and the concentration-depth distribution of trace elements in the solid electrolyte interphase (SEI) film; and characterized the kinetic behavior and features of the elementary steps (mass transfer, charge transfer, electro-crystallization) at Li-electrolyte interface using microelectrode technology and various electrochemical test methods. The results show that the lithium metal anode has better cycling performance in high concentration and localized high concentration electrolyte. At the same time, the experimental results confirm that the formation of spherical crystal nucleus is favored only under certain chemical conditions and certain reaction rate; under these conditions, the induction period and the self-smoothing process of critical crystal nucleus can be found. It suggests that there are determined causal among the apparent performance of lithium metal anode, the kinetic parameters of the interfacial charge transfer step and the electro-crystallization step, and these correlations can be used as a reference for screening and evaluating electrolyte systems and battery operating conditions, providing a reliable kinetic basis for future work.

Impact of Pressure Distribution and Magnitude on the Performance of Lithium Metal Anodes

Li metal anodes are a critical battery technology due to their ability to substantially increase the energy density of Li-based batteries. It is well known that pressure greatly impacts the performance of a Li-metal anode. However, precisely how the pressure value and distribution of pressure affect performance is unclear. Furthermore, the solid-electrolyte interphase composition that forms under varying pressure distributions remains a key parameter for practical lithium metal anodes. In this work, different pressure distributions were employed by using differently shaped and oriented mechanical springs in the coin cells, resulting in varying contact points. Pressure-sensitive films were used to spatially map the pressure and correlate it to the performance. It was found that higher average pressure does not necessarily have a positive effect on performance. When high pressure is paired with poor pressure uniformity, the performance is in fact worse likely due to the current focusing effect, rendering unsatisfied cycling stability. This work points to the importance of controlling the relationship between average pressure and pressure uniformity.

MXene-BN-Introduced Artificial SEI to Inhibit Dendrite Growth of Lithium Metal Batteries.

Lithiophilic substrates have been shown to improve the electrochemical performance of lithium metal anodes. The MXene-BN/Cu 3D current collector was prepared by a filtration method. The artificial solid electrolyte interface (SEI) layer composed of Li3N and LiF was formed on the surface of MXene-BN/Cu during the Li deposition process. Volume changes can be effectively relieved by this special 3D structure. The artificial SEI film reduced the critical dendrite growth length, inhibited Li dendrite growth, and stabilized the electrochemical cycle. MXene-BN/Cu exhibited highly reversible cycling properties during lithium metal deposition with a high Coulombic efficiency of ∼ 98.0% over 500 cycles. Furthermore, LiBH4 was produced during the Li deposition process. This study presents a promising strategy for developing dendrite-free Li anodes for use in lithium metal batteries.

In-situ synthesis of fluoropolymer-grafted Nanohybrid electrolyte as ion reservoir for Li-metal batteries

Heterogeneity in ion flux of electrolyte materials largely dictates the growth of lithium dendrites and performance of lithium metal anode, which is considered “holy grail” to enable safe rechargeable batteries with ultrahigh energy density. This challenge is even more prominent in polymer-based electrolytes, which thereby leads to uneven ion distribution and mobility of ionic charge carriers, disturbing electrodeposition. In this work, we propose an ion-immobilization strategy achieved by an in-situ grafted nanohybrid fluoropolymer electrolyte, which takes advantages of unique weak solvation of fluoropolymers to tether anions to solvation structure of Li+. Such regulation in conjunction with the well dispersed nanometric aggregates, enables polymer electrolytes serving as ion reservoirs with strengthened weakly-solvating effect. As such, we suppressed formation of dendritic lithium by inducing uniform ion distribution, which significantly extended cell lifetime to over 1900 h in electrodeposition and prolonged charge-discharge cycles of in-situ lithium metal batteries up to 4.6 V at ambient temperature. This work demonstrates a new approach to regulate interfacial chemistry of Li anode and access high-performance polymer-based electrolytes.

Boosting the Performance of Lithium Metal Anodes with Three-Dimensional Lithium Hosts: Recent Progress and Future Perspectives

Li metal has emerged as a promising anode material for high energy density batteries, due to its low electrochemical potential and high specific capacity of 3860 mAh·g−1. These characteristics make it an attractive choice for electric vehicles and power grids. However, Li-metal batteries are plagued by dendrite issues stemming from the high reactivity of Li metal, which can ultimately result in battery failure or even safety concerns. To overcome this challenge, various strategies have been proposed to prevent dendrite formation and enhance the safety of Li-metal batteries. This review critically examines the recent progress in the development of dendrite-free Li-metal batteries, with a particular emphasis on advanced approaches of 3D Li metal host construction. Our goal is to provide a comprehensive overview of the 3D hosts for suppressing Li dendrites and to offer guidance for the future development of superior Li metal batteries.

Decreasing Interfacial Pitfalls with Self-Grown Sheet-Like Li2 S Artificial Solid-Electrolyte Interphase for Enhanced Cycling Performance of Lithium Metal Anode.

Constructing a 3D composite Li metal anode (LMA) along with the engineering of artificial solid electrolyte interphase (SEI) is a promising strategy for achieving dendrite-free Li deposition and high cycling stability. The nanostructure of artificial SEI is closely related to the performance of the LMA. Herein, the self-grown process and morphology of in situ formed Li2 S during lithiation of Cux S is studied systematically, and a large-sized sheet-like Li2 S layer as an artificial SEI is in situ generated on the inner surface of a 3D continuous porous Cu skeleton (3DCu@Li2 S-S). The sheet-like Li2 S layer with few interfacial pitfalls (Cu/Li2 S heterogeneous interface) possesses enhanced diffusion of Li ions. And the continuous porous structure provides transport channels for lithium-ion transport. As a result, the 3DCu@Li2 S-S presents a high Coulombic efficiency (99.3%), long cycle life (500 cycles), and high-rate performance (10mA cm-2 ). Furthermore, Li/3DCu@Li2 S anode fabricated by thermal infusion method inherits the synergistic advantages of sheet-like Li2 S and continuous porous structure. The Li/3DCu@Li2 S anode shows significantly enhanced cycling life in both liquid and solid electrolytes. This work provides a new concept to design artificial SEI for LMA with high safe and high performance.

(Invited) Identification of Lithium Hydride and Nanocrystalline Lithium Fluoride in the SEI of Lithium Metal Anodes and the Stabilization of High Ni Layered Structure at Ultra-High Voltage through Cathode Electrolyte Interphase Engineering

Solid-electrolyte interphase (SEI) plays a pivotal role in the performance of lithium metal anode, which is promising for high energy batteries. Understanding SEI composition is important but very challenging. Here we report on the use of synchrotron-based X-ray diffraction and pair distribution function analysis to identify and differentiate the two elusive components, LiH and LiF, in the SEI of lithium metal anodes. LiH is identified as a component of SEI in high abundance, and the possibility of its misidentification as LiF in the literature is discussed. LiF in the SEI is found to have different structural features from LiF in bulk phase, including larger lattice parameter and smaller grain size (<3 nm). These characteristics favor Li+ transport, and explain why an ionic insulator, like LiF, has been found to be a favored component for SEI. PDF analysis of the SEI reveals key amorphous components related to solvent or anion decomposition.Nickel-rich layered cathode materials with high energy density are very promising for next generation batteries when coupled with lithium metal anode. However, the practical capacities accessible are far less than the theoretical value due to their structural instability during cycling, especially when charged at high voltages. Such challenge has been attributed to the concomitant electrolyte instability and cathode structural and morphological degradation. Therefore, various approaches have been developed through electrolyte engineering and bulk cathode material modifications. In this presentation, we will report a simple interphase engineering approach by using an ionic electrolyte additive, lithium difluorophosphate (LiDFP). Through theoretical calculation, we found that self-decomposition product PO2F of LiDFP additive is adsorbed strongly and uniformly on the Ni-rich cathode, which is further decomposed to Li3PO4 and LiF through the catalytic effect of transition metals. The new interphasial chemistry contributed from LiDFP stabilizes the bulk structure of Ni-rich cathode materials and prevents the performance degradation by suppressing the dissolution of transition metals and undesired structural changes. Even after 200 cycles with charge limit as high as 4.8 V, no rock-salt phase can be detected in LiNi0.76Co0.10Mn0.14O2 (NMC76), and the cell consisting of NMC76 cathode and lithium metal anode retains 97% of the initial capacity (235 mAh/g). Various advanced characterizations were used, on both atomic and electrode levels, to reveal the mechanism how a new interphase stabilizes the layer structures in bulk electrode. The dissolution of nickel was identified to be most serious at high voltage, rather than the widely believed manganese dissolution. The transition metal dissolution can be effectively suppressed by LiDFP additive. Furthermore, the cathode surface protected by LiDFP-derived interphase is shown to regulate a more uniform lithium distribution within the bulk cathode particles and effectively mitigate the strain and crack formation. Machine-learning assisted nano-tomography discovered that such interphase-bulk interaction is most effective for those small-sized, spherically-shaped particles.Acknowledgement:The work done at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. DOE through the Advanced Battery Materials Research (BMR) Program, (Battery500 Consortium), and Applied Battery Research for Transportation (ABRT) program under contract No. DE-SC0012704. This work used the resources of the Center for Functional Nanomaterials, a U.S. DOE office of Science User Facility, at Brookhaven National Laboratory, and beamlines 5-ID, 7-BM, 23-ID-2, and 28-ID-2 of the National Synchrotron Light Source II, a US DOE Office of Science user facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The work done at Pacific Northwest National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy through the Advanced Battery Materials Research (BMR) Program (Battery500 Consortium) under contract No. DE-AC02-05CH11231. The work at ARL was performed under JCESR, an Energy Research Hub funded by Basic Energy Science, US Department of Energy.

A carbon cloth with a coating layer containing aluminum fluoride as an interlayer for lithium metal batteries

Problems in safety and cell performance from dendritic growth of lithium and formation of dead lithium on the surface of electrode during charge has impeded commercialization of lithium metal as an electrode of lithium rechargeable batteries. To solve these problems, use of lithiophilic materials on lithium metal electrode has been suggested. Herein, we propose an interlayer for lithium metal battery composed of carbon cloth with a coating layer containing lithiophilic aluminum fluoride (AlF3). The positive effects of AlF3-containing layer on the carbon cloth on the performance of lithium metal anode are investigated through cycling of Li||Li symmetric and LiCoO2||Li half-cells. We demonstrate that the enhanced cycling stability with the interlayer is attributed to the LiF-rich SEI layer in-situ formed from the reaction between AlF3 and lithium-ions in cycling and suppressed formation of dendrites and dead lithium during lithium plating process. The LiF-rich SEI layer on the carbon cloth induces uniform plating of lithium above and inside the interlayer while the bare carbon cloth results in irregular and local plating of lithium. The reduced decomposition of the electrolyte by the AlF3-containing layer is also considered to be the reason for the improved cycling stability of the lithium metal anode.

A two-step strategy for constructing stable gel polymer electrolyte interfaces for long-life cycle lithium metal batteries

Due to the high reactivity between the lithium metal and traditional organic liquid electrolyte, the reaction of lithium metal electrode is usually uneven and there are also unexpected side reactions. Therefore, construction of a stable solid electrolyte interface (SEI) is highly essential to improve the performance of lithium metal anode. Herein, a sandwich-like gel polymer electrolyte (GPE) is accurately prepared by in-situ polymerization of Polyacrylonitrile (PAN) nanofiber membrane with trihydroxymethylpropyl trimethylacrylate (TMPTMA) and 1,6-hexanediol diacrylate (HDDA). The resulting GPE with a tightly cross-linked gel skeleton exhibits high ionic conductivity and electrochemical window of 5.6 V versus Li/Li+. In particular, the pretreatment of Li metal anode can improve the interfacial wettability, and the synergy of the chemically pretreated Li metal anode surface and the GPE can electrochemically in situ generate SEI with compositionally stable and fluorine-rich inorganic components. Owing to these unique advantages, the interfacial compatibility between the GPE and lithium metal is greatly improved. Meanwhile, the formed SEI can inhibit the formation of lithium dendrites, and decomposition of GPE would be alleviated. The assembled Li-FEC|GPE|LiFePO4 full cell shows a high initial discharge capacity of 157.1 mA h g−1, and maintains a capacity retention of 92.3% after 100 cycles at 0.2C.

Graphene Oxide over-Layer on Liquid Metal Coated Cu Current Collector for Improved Cycle Performance of Lithium Metal Anode

Lithium metal is a promising anode material for Li-ion batteries because of its high specific capacity and negative electrochemical potential. However, there are two major challenges that need to be overcome before it can be used in practical applications: (1) Formation of dendrites that can cause short circuit of the cell leading to safety issues and (2) decomposition of electrolyte when contacting the reactive lithium metal that shortens the cycle lifetime. Keys to realize the lithium metal anode for practical application is to enable uniform deposition of lithium metal preventing dendrites and develop stable solid electrolyte interface (SEI) layer between lithium metal and the electrolyte.In this work, we propose a liquid metal (LM) coated on a copper current collector with graphene oxide (GO) overlayer to grow a stable SEI to uniformly deposit Li and protect it from direct contact with the electrolyte by SEI grown on GO. First, preconditioning was performed to develop SEI on the top layer of the anode. Ga-Sn-In alloy, which is in a liquid state at room temperature, inproves wetting of lithium promoting the uniform deposition and prevents the nucleation of the dendrites. Due to the high wettability of the LM against lithium and the SEI layer, the lithium deposition takes place between the LM and the to SEI layer preventing direct contact of lithium with the electrolyte and undesired chemical reactions.The effect of GO/LM coating was verified using a Li-Li symmetric cell. The result showed significant reduction in the reaction overpotentials on compared with LM coated and bare Cu current collectors. The low and symmetric reaction potentials were observed even after increasing the current density and areal capacity to 4.0 mA/cm2 and 8.0 mAh/cm2, respectively. Scanning electron microscopy (SEM) analysis of GO/LM coating before and after the conditioning and Li pre-deposition revealed even after the large amount of Li plating (> 6 mAh/cm2) the surface remains flat without any dendrites. This indicates a stable artificial SEI layer was formed and Li was deposited between the LM and the SEI layer. A full-cell test using LiNi1/3Co1/3Mn1/3O2 cathode with GO/LM anode showed much improvement in the cycle lifetime compared with the simple LM-coated and bare Cu. Figure caption : SEM images of SEI development and lithium plating on GO/LM coated Cu current collector. Figure 1

Influence of Polysulfides on the Lithium Metal Anode and on Electrolyte Properties

Because the electrification of our society has progressed rapidly in recent years, new high-performance batteries are needed to store electrical energy. Lithium-sulfur (Li-S) batteries have attracted a lot of interest in the last years due to the high theoretical specific capacity of sulfur (1672 mA h gS -1), its extraordinary theoretical specific energy of 2500 W h kg-1, the high abundance and therefore low cost of sulfur.[1] The charging and discharging mechanism of the Li-S battery is significantly different from the state of the art lithium-ion batteries. During the lithiation and delithiation of sulfur to lithium sulfide various long- and short-chain polysulfides (PS) emerge as intermediate reaction products.[2] In this work, we characterize the influence of varying amounts of polysulfides on the electrochemical performance of lithium metal anodes in sparingly solvating solvents. The addition of PS decreases and stabilizes the overpotential in Li/Li cells and therefore delays the cell degradation. The origin of this improvement is characterized by several ex-situ and operando analytical techniques such as optical microscopy, XPS and impedance spectroscopy.[3] One side effect of a higher polysulfide solubility is an increase in the electrolyte viscosity and therefore decrease in the ionic conductivity as well as an increased polysulfide shuttle. To analyse this hypothesis, the amount of dissolved polysulfides, viscosity and ionic conductivity of three different electrolytes are compared and discussed.Conclusions for electrolyte design towards overall improved Li-S cell performance will be presented based on these results. Reference s : [1] A. Manthiram, S.-H. Chung, C. Zu, Adv. Mater. 2015, 27, 1980. [2] M. Wild, L. O'Neill, T. Zhang, R. Purkayastha, G. Minton, M. Marinescu, G. J. Offer, Energy Environ. Sci. 2015, 8, 3477.[3] F. S. Reuter, C.‐J. Huang, Y.‐C. Hsieh, S. Dörfler, G. Brunklaus, H. Althues, M. Winter, S. D. Lin, B.‐J. Hwang, S. Kaskel, Batteries Supercaps 2021, 4, 347.

Influence of Temperature and Electrolyte Composition on the Performance of Lithium Metal Anodes

Lithium metal anodes have again attracted widespread attention due to the continuously growing demand of cells with higher energy density. However, the lithium deposition mechanism and the affecting process of influencing factors, such as temperature, cycling current density, and electrolyte composition are not fully understood and require further investigation. In this article, the behavior of lithium metal anode at different temperatures (25, 40, and 60 ∘C), lithium salts, electrolyte concentrations (1 and 2 M), and the applied cell current (equivalent to 0.5 C, 1 C, and 2 C). is investigated. Two different salts were evaluated: lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesul-fonyl)imide (LiTFSI). The cells at a medium temperature (40 ∘C) show the highest Coulombic efficiency (CE). However, shorter cycle life is observed compared to the experiments at room temperature (25 ∘C). Regardless of electrolyte type and C-rate, the higher temperature of 60 ∘C provides the worst Coulombic efficiency and cycle life among those at the examined temperatures. A higher C-rate has a positive effect on the stability over the cycle life of the lithium cells. The best performance in terms of long cycle life and relatively good Coulombic efficiency is achieved by fast charging the cell with high concentration LiFSI in 1,2-dimethoxyethane (DME) electrolyte at a temperature of 25 ∘C. The cell has an average Coulombic efficiency of 0.987 over 223 cycles. In addition to galvanostatic experiments, Electrochemical Impedance Spectroscopy (EIS) measurements were performed to study the evolution of the interface under different conditions during cycling.

Lithiophilic MXene‐Guided Lithium Metal Nucleation and Growth Behavior

AbstractThe positive effects of a lithiophilic substrate on the electrochemical performance of lithium metal anodes are confirmed in several reports, while the understanding of lithiophilic substrate‐guided lithium metal nucleation and growth behavior is still insufficient. In this study, the effect of a lithiophilic surface on lithium metal nucleation and growth behaviors is investigated using a large‐area Ti3C2Tx MXene substrate with a large number of oxygen and fluorine dual heteroatoms. The use of the MXene substrate results in a high lithium‐ion concentration as well as the formation of uniform solid–electrolyte‐interface (SEI) layers on the lithiophilic surface. The solid–solid interface (MXene‐SEI layer) significantly affects the surface tension of the deposited lithium metal nuclei as well as the nucleation overpotential, resulting in the formation of uniformly dispersed lithium nanoparticles (≈10–20 nm in diameter) over the entire MXene surface. The primary lithium nanoparticles preferentially coalesce and agglomerate into larger secondary particles while retaining their primary particle shapes. Subsequently, they form close‐packed structures, resulting in a dense metal layer composed of particle‐by‐particle microstructures. This distinctive lithium metal deposition behavior leads to highly reversible cycling performance with high Columbic efficiencies &gt; 99.0% and long cycle lives of over 1000 cycles.

Decorating carbon felt with oxides by dipping as dendrite-free host for lithium metal anode

Although 3D frameworks as collectors have been proved to improve the electrochemical performance of lithium metal anodes, the development of lithiophilic frameworks to form a compact anode is still desired. Hence, we developed lithiophilic carbon felt by decorating with metallic oxides (e.g. ZnO, NiO, Co3O4, Fe2O3, CuO) using a facile dipping method to improve lithiophilicity that can spontaneously infuse molten lithium into the frameworks. The formed composite anode possessed superior advantages and can uniform lithium nuclear. Thus, the composite anode delivered enhanced cycling performance under 10 mA cm−2 for 1 mAh cm−2 for 500 cycles and even under 10 mA cm−2 for 2 mAh cm−2 for 500 cycles. The assembled full cell coupled with LiFePO4 also exhibited excellent cycling performance and lower polarization. More importantly, our work not only improves the design of the lithium metal anodes but also provides an effective way for the practical uses in a large scale.

Solid‐State Lithium–Sulfur Battery Enabled by Thio‐LiSICON/Polymer Composite Electrolyte and Sulfurized Polyacrylonitrile Cathode

AbstractSolid‐state lithium–sulfur battery (SSLSB) is attractive due to its potential for providing high energy density. However, the cell chemistry of SSLSB still faces challenges such as sluggish electrochemical kinetics and prominent “chemomechanical” failure. Herein, a high‐performance SSLSB is demonstrated by using the thio‐LiSICON/polymer composite electrolyte in combination with sulfurized polyacrylonitrile (S/PAN) cathode. Thio‐LiSICON/polymer composite electrolyte, which processes high ionic conductivity and wettability, is fabricated to enhance the interfacial contact and the performance of lithium metal anodes. S/PAN is utilized due to its unique electrochemical characteristics: electrochemical and structural studies combined with nuclear magnetic resonance spectroscopy and electron paramagnetic resonance characterizations reveal the charge/discharge mechanism of S/PAN, which is the radical‐mediated redox reaction within the sulfur grafted conjugated polymer framework. This characteristic of S/PAN can support alleviating the volume change in the cathode and maintaining fast redox kinetics. The assembled SSLSB full cell exhibits excellent rate performance with 1183 mAh g−1 at 0.2 C and 719 mAh g−1 at 0.5 C, respectively, and can accomplish 50 cycles at 0.1 C with the capacity retention of 588 mAh g−1. The superior performance of the SSLSB cell rationalizes the construction concept and leads to considerations for the innovative design of SSLSB.

Air-stable means more: designing air-defendable lithium metals for safe and stable batteries

This review summarizes the strategies to simultaneously enhance air/water-resistance and electrochemical performance of lithium metal anodes.

Inducing the Formation of In Situ Li3N-Rich SEI via Nanocomposite Plating of Mg3N2 with Lithium Enables High-Performance 3D Lithium-Metal Batteries.

Lithium metals fit the growing demand of high-energy density rechargeable batteries because of their high specific capacity and low redox potential. However, the lithium-metal anodes are abandoned because of various defects. In this study, we apply composite plating into the protection of lithium-metal anodes. We confirmed that the Mg3N2 nanoparticle dispersed in the ether electrolyte can be easily composite-plated with lithium, resulting in a flat, dense, and dendrite-free lithium deposition layer during the electrodeposition process. In addition, the Mg3N2 plated in the lithium metal phase would react with lithium and then generate a Li3N-rich solid electrolyte interphase (SEI) layer, mitigating continuous side reactions of the electrolyte on the Li metal. In addition, another product of the reaction is Mg which can work as lithiophilic sites in electrodeposition. The combined effect of the two fields can effectively improve the performance of lithium metal anodes. The Li3N-rich SEI layer would grow well on the surface of the three-dimensional (3D) lithium anode by composite plating. Furthermore, composite plating with the Mg3N2-containing electrolyte is a viable route that can be used for various 3D current collectors easily with a small volume effect. Here, we show that the composite plating 3D lithium metal anode is successfully applied in the Li-S battery with a long lifetime.

Composite Anode of Lithium Metal Powder and Graphite for Improving Performance of Lithium Metal Anode

Over the last several decades, new battery technologies have been developed due to the need for consistently high energy density batteries. Lithium metal is the ideal cathode for next-generation lithium batteries, because it has a high specific capacity (3860 mAh g−1) and the lowest reduction potential (−3.040 V vs. standard hydrogen electrode, SHE). However, safety issues caused by Li dendritic growth during Li plating interfere with the use of lithium metal-based rechargeable batteries. Li dendrites can cause dead lithium to accumulate on the lithium metal surface, resulting in increased resistance at the interface or short-circuiting, which can lead to explosion. Several studies have been proposed to inhibit the growth of lithium dendrites, such as electrolyte additives, surface coating, separator modification, and lithium metal host. In this experiment, Li was isolated by physically mixing Li and graphite to form a composite electrode, thereby suppressing Li dendrite growth. Li metal powder is synthesized by the droplet emulsion technique and this shape is prohibited dendrite growth. These Li metal powder+graphite composite anode was experimented with constant current charge/discharge tests and constant voltage tests. And the structure, morphology, and electrochemical properties of the new type of battery’s electrode were investigated by the implementation of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectroscopy (EDS). The result was analyzed by electrochemical impedance spectroscopy (EIS).

Endowing the Lithium Metal Surface with Self-Healing Property via an in Situ Gas-Solid Reaction for High-Performance Lithium Metal Batteries.

The property of the solid electrolyte interphase (SEI) layer is of prime importance for the performance of lithium metal anodes. Replacing the spontaneously formed inhomogeneous and unstable SEI layer with a high-performance artificial SEI is an effective strategy. Herein, a self-healing SEI layer with high lithium-ion conductivity and a stable framework to address the issues of poor performance of lithium metal anodes is achieved. C, Li2S, and LiI are uniformly distributed on the lithium surface via a "sauna" reaction between CS2-I2 mixed steam and metal lithium, which has the potential to be applied to large-scale preparation. The obtained SEI layer possesses high mechanical strength and facilitated lithium-ion transport capability, which are inherited from the amorphous C and lithium compounds (Li2S and LiI). Most importantly, the LiI component can migrate through the electrolyte and cover the exposed lithium caused by flaws and cracks, leading to a self-healing property. As a result, the C-Li2S-LiI@Li electrode exhibits excellent electrochemical performance with low overpotential and long lifespan.