Overpotential Deposition Research Articles

Atomically Dispersed Zincophilic Sites in N,P-Codoped Carbon Macroporous Fibers Enable Efficient Zn Metal Anodes.

Zn dendrite growth and undesired parasitic reactions severely restrict the practical use of deep-cycling Zn metal anodes (ZMAs). Herein, we demonstrate an elaborate design of atomically dispersed Cu and Zn sites anchored on N,P-codoped carbon macroporous fibers (denoted as Cu/Zn-N/P-CMFs) as a three-dimensional (3D) versatile host for efficient ZMAs in mildly acidic electrolyte. The 3D macroporous frameworks can alleviate the structural stress and suppress Zn dendrite growth by spatially homogenizing Zn2+ flux. Moreover, the well-dispersed Cu and Zn atoms anchored by N and P atoms maximize the utilization as abundant active nucleation sites for Zn plating. As expected, the Cu/Zn-N/P-CMFs host presents a low Zn nucleation overpotential, high reversibility, and dendrite-free Zn deposition. The Cu/Zn-N/P-CMFs-Zn electrode exhibits stable Zn plating/stripping with low polarization for 630 h at 2 mA cm-2 and 2 mAh cm-2. When coupled with a MnO2 cathode, the fabricated full cell also shows impressive cycling performance even when tested under harsh conditions.

Interfacial Engineering of Magnesiophilic Coordination Layer Stabilizes Mg Metal Anode

AbstractRechargeable magnesium batteries (RMBs) are seriously plagued by the direct exposure of the Mg anode to the electrolyte components, leading to spontaneous and electrochemical side reactions and interfacial passivation. Herein, a benign coordination layer is constructed at the Mg/electrolyte interface where aniline with a strong magnesiophilic amine group and high stability to Mg is chosen as representative, which has higher adsorption energy than DME (1,2‐dimethoxyethane) and trace water. This Mg coordination environment mitigates side reactions, forming a non‐passivating interface consisting of aniline and much fewer by‐products after several cycles. Therefore, the Mg symmetrical cell operates with a low overpotential and uniform Mg0 deposition. This interfacial coordination can also be adopted for Mg anode protection in various electrolyte cases of Mg(TFSI)2 electrolyte systems.

Interfacial Engineering of Magnesiophilic Coordination Layer Stabilizes Mg Metal Anode.

Rechargeable magnesium batteries (RMBs) are seriously plagued by the direct exposure of the Mg anode to the electrolyte components, leading to spontaneous and electrochemical side reactions and interfacial passivation. Herein, a benign coordination layer is constructed at the Mg/electrolyte interface where aniline with a strong magnesiophilic amine group and high stability to Mg is chosen as representative, which has higher adsorption energy than DME (1,2-dimethoxyethane) and trace water. This Mg coordination environment mitigates side reactions, forming a non-passivating interface consisting of aniline and much fewer by-products after several cycles. Therefore, the Mg symmetrical cell operates with a low overpotential and uniform Mg0 deposition. This interfacial coordination can also be adopted for Mg anode protection in various electrolyte cases of Mg(TFSI)2 electrolyte systems.

Mixed Phase Nickel‐Cobaltite for High Energy Density Asymmetric Supercapacitor using Cathodic Overpotential Synthesis Route

AbstractFor flexible solid‐state electronics, it is essential to accelerate the transition to renewable materials and environmentally friendly manufacturing procedures. Symmetric supercapacitors (SCs) have a limited voltage window and capacity, hampering their use in practical applications such as portable electronics, hybrid vehicles, and transportation. To improve the energy density of supercapacitors, the strategy of using an advanced pseudo‐capacitive electrode in an asymmetric device configuration is feasible and effective. Here, we report on the design and synthesis of hierarchical honeycomb‐like morphology with controlled Ni/Co molar ratios of NiCo2O4 (NCO) coatings on flexible stainless‐steel substrates utilizing high cathodic overpotential deposition. The NCO electrode retains 90.5% of the three‐electrode capacitance (911 F g−1, or 594 C g−1) even after increasing the current density to 10 A g−1 (∼10 times). Furthermore, we have fabricated a 1.5 V asymmetric supercapacitor (ASC, NCO//AC); such a device delivers maximum specific energy and specific power of 76.8 Wh kg−1 and 16858 W kg−1 in 2 M KOH electrolyte and excellent cycling stability (∼88% retention after 5000 cycles).

Effects of F− ions on the electrochemical and interface behavior of cathodes in zinc electrowinning

The increasing use of Zn metal in the energy and industrial sectors necessitates a higher level of research into the zinc electrowinning process. In this work, the effects of fluoride ions (F−) in zinc electrolyte on the cathodic kinetics and zinc product quality during zinc electrodeposition was systematically investigated via a series analysis. The results revealed that the addition of F− in the electrolyte showed a polarization effect, with an increase in the apparent cathodic exchange current density increased by 104 orders of magnitude, and a decrease in the zinc deposition overpotential by 46 mV at a concentration of 400 mg/L. However, F− also reduces the hydrogen evolution overvoltage, when the electrolyte contains 400 mg/L F−, the hydrogen evolution overvoltage on aluminum cathode and zinc cathode decreases by 121 mV and 97 mV, respectively. The promoted hydrogen evolution kinetics increases energy consumption and surface porosity. Additionally, F− ions corrode the Al2O3 oxide film on the cathode surface, accelerating the corrosion of the aluminum cathode plate. This results in increased adhesion of zinc deposition to the damaged aluminum substrate, making it difficult to peel off.

Construction of Synchronous-Deposition K Metal Anodes Via Modulation of Ion/Electron Transport Kinetics for High-Rate and Low-Temperature K Metal Batteries.

The construction of conductive scaffolds is demonstrated to be an ideal strategy to alleviate the volume expansion and dendrite growth of K metal anodes. Nevertheless, the heterogeneous top-bottom deposition behavior caused by incompatible electronic/ionic conductivity of three-dimensional (3D) skeleton severely hinders its application. Here, a K2 Se/Cu conducting layer is fabricated on the Cu foam so as to enhance ionic transport and weaken electronic conductivity of the skeleton. Then, an excellent simultaneous deposition behavior of K metal inside the host is obtained for the first time via tuning fast ionic transport and low electronic conductivity. The simultaneous deposition mode can not only utilize the entire 3D structure to accommodate the volume expansion during K deposition but also avoid the formation of K dendrites at high current and ultra-low temperature. Consequently, the symmetric cells present a long cycle lifespan over 1000h with a low deposition overpotential of 80mV at 1mA cm-2 . Furthermore, the full cell matching with the perylene-tetracarboxylic dianhydride (PTCDA) cathode presents an outstanding cycle lifespan over 600 cycles at 5 C at -20°C. The proposed simultaneous deposition strategy provides a new design direction for the construction of dendrite-free K metal anodes.

Optimized Solid Electrolyte Interphase and Solvation Structure of Potassium Ions in Carbonate Electrolytes for High-Performance Potassium Metal Batteries.

The introduction of electrolyte additives is one of the most potential strategies to improve the performance of potassium metal batteries (PMBs). However, designing an additive that can alter the K+ solvation shell and essentially inhibit K dendrite remains a challenge. Herein, the amyl-triphenyl-phosphonium bromide wasintroduced as an additive to build a stable solid electrolyte interphase layer. The amyl-TPP cations can form a cation shielding layer on the metal surface during the nucleation stage, preventing K+ from gathering at the tip to form Kdendrites. Besides, the cations can be preferentially reduced to form Kx Py with fast K+ transport kinetics. The Br- anions, as Lewis bases with strong electronegativity, can not only coordinate the Lewis acid pentafluoride to inhibit the formation of HF, but also change the K+ solvation structure to reduce solvent molecules in the first solvation structure. Therefore, the symmetrical battery exhibits a low deposition overpotential of 123mV at 0.1mAcm-2 over 4200h cycle life. The full battery, paried with a perylene-tetracarboxylic dianhydride (PTCDA) cathode, possesses a cycle life of 250 cycles at 2C and 81.9% capacity retention. This work offers a reasonable electrolyte design to obtain PMBs with long-term stablity and safety.

Understanding the Polymorphism of Cobalt Nanoparticles Formed in Electrodeposition-An In Situ XRD Study.

An advanced synchrotron-based in situ X-ray diffraction (XRD) technique is successfully developed and employed to track and monitor the formation and phase selection of cobalt (Co) in electrodeposition in real time and verify DFT computational results. The impacts of a number of controlling factors including the pH of the electrolyte and deposition overpotential are systematically studied. The results show that the yielded phase of the electrodeposited Co is controlled by both thermodynamics and kinetics. The low pH low overpotential condition favors the formation of the thermodynamically stable fcc phase. While the high pH high overpotential condition promotes the formation of the metastable hcp phase. The experimental results agree well with the nanometric phase diagram computed with DFT. Layer-by-layer alternative stacking of fcc-hcp polymorphic phases can be facilely fabricated by just varying the overpotential. This work not only offers an effective means to control the phase of electroplating of Co but also presents a new approach to reveal the fundamental insights of the formation of metals under electrochemical reduction driving force.

Ultrathin hierarchical porous Cu current collector fabricated by anodic oxidation in complexing agent system for stable anode-free Lithium metal batteries

3D porous Cu current collectors, as the host for Li metal deposition in Li metal batteries, shows great potential in inhibiting Li dendrite growth. A method of fabricating ultrathin porous Cu with 3D hierarchical micronanostructures by electrochemically oxidizing of planar Cu in complexing agent electrolytes, at controlled electrolyte temperature, is introduced in this work. When applied as the anode current collector of anode-free Li metal batteries, the micropores inside the 3D porous Cu provide a large amount of Li accommodating space and accelerates the diffusion rate of lithium ions. The uniformly distributed 3D micro/nanopores effectively homogenizes the local electric field and induce homogeneous deposition of Li, thereby inhibiting the growth of Li dendrites and forming stable SEI layers. The hierarchically structured micro/nanoporous Cu current collector presents low nucleation overpotential and stable Li deposition behavior at 0.5 mA cm−2. Compared with the Cu current collector, the full-cell (Cu//LiFePO4) capacity retention assembled by this structure is improved from 10.2% to 55.5% at 100 cycles with 0.2 C rate, and the Coulombic efficiency is as high as 98.3%. This work provides a feasible and scalable method to fabricate hierarchical porous Cu for dendrite-free and high-capacity retention anode-free Li metal batteries.

Over- and underpotential deposition of copper from a deep eutectic solvent: Pt(1 1 1) single crystal versus polycrystalline Pt substrates

• Deposition/dissolution of Cu on Pt from ethaline occur in one-electron reactions. • A full (1x1) monolayer of Cu adatoms is formed on Pt(111) in ethaline. • No voltammetric signals of Cu UPD were observed for Pt(poly) in ethaline. • Surface structure determines the mechanism and rate of Cu OPD at the initial stages. • Cu OPD on Pt(111) and Pt(poly) in ethaline occurs via 2D and 3D growth, respectively. Deep eutectic solvents (DESs) attract ever greater interest as nonaqueous media for the electrodeposition of metals and alloys. This work investigates the initial stages of Cu electrodeposition from DES representing a mixture of choline chloride and ethylene glycol (ChCl:EG) with a (1:2) molar ratio that contains CuCl or CuCl 2 salts. These studies were performed by means of cyclic voltammetry and scanning probe microscopy on single-crystalline Pt(111) and polycrystalline Pt(poly) electrodes. Additional experiments on Cu deposition were carried out using an aqueous Cl - -rich solution (3 M NaCl + 0.01 M CuCl). The process of Cu underpotential deposition (UPD) on the surface of Pt(111) in DES is observed for the first time. It is proposed that a complete (1x1) monolayer of Cu adatoms is formed at potentials more positive than the onset of overpotential deposition (OPD). The comparison of results for Pt(111) and Pt(poly) in ChCl:EG (1:2) and in the aqueous 3 M NaCl solution confirms that the surface morphology and (co)adsorption of solution components play an important role in the Cu UPD process. In DES, as well as in the aqueous solutions containing CuCl, Cu OPD occurs via the reduction of Cu(I) ions. The Cu(I)/Cu(II) redox transition was observed at significantly more positive potentials. We conclude on the basis of voltammetry and in situ scanning tunneling microscopy (STM) data that the mechanism of Cu electrodeposition in DES is determined by the surface structure. STM data demonstrate the layer-by-layer growth of a two-dimensional Cu deposit on Pt(111), while the resulting Cu deposit on Pt(poly) is characterized by a grain-like morphology. We also demonstrate that the mechanism of Cu OPD affects the initial deposition rate under conditions of diffusion limitations.

Evaluation of Electrochemical Properties of Aluminum Electrolytes with Ammonium Salt Using an Ultramicro Disk Electrode

Cyclic voltammetry of a DMSO2–AlCl3 electrolyte was performed using an ultramicro disk electrode to evaluate the effects of ammonium salts on the Al electrodeposition reaction. A side reaction in the electrolyte at potentials more negative than −0.8 V (vs Al-wire) was found to suppress the Al electrodeposition reaction. The addition of even a small amount of NH4Cl promoted an Al electrodeposition reaction, which proceeded at more positive potentials than the side reaction. With the excessive addition of tetramethylammonium chloride (TMAC) electrolyte, the Al electrodeposition reaction was also suppressed, proceeding in the negative potential region where a side reaction occurs. In the electrolyte containing 0.02-mol NH4Cl and 1.0-mol TMAC, a decrease in the deposition overpotential on the reducing side and an increase in the dissolution current on the oxidizing side were observed simultaneously.

High Purity Pd Nanofilm Deposition Via Cu Incorporation Control in Slrr Process

Department of Materials Science & Chemical Engineering, Hanyang University, Ansan 15588, Korea *byyoo@hanyang.ac.kr ABSTRACT The deposition of palladium has been considered in many industrial applications and in fundamental science because of the high catalytic activities. Careful control of smooth and continuous Pd film less than 1nm thickness is critical for achieving highly active catalysts. Furthermore, perspective of cost-effective view, minimum usage of Pd is essential for catalyst while showing maximum activity for catalyst due to its high cost.Electrochemical-atomic layer deposition (E-ALD), can achieve the growth of atomic level of metal film under room temperature and simple condition. E- ALD protocol proceeds using surface limited redox replacement (SLRR). SLRR involves 2 step. First, Au substrate is covered with Cu monolayer, the result of underpotential deposition of Cu (sacrificial element). Underpotential deposition (UPD) is the deposition occurs at more positive potential than equilibrium potential which the potential where deposition actually strats and UPD can limit Cu deposition by atomic layer. Second, Cu atomic layer is replaced by more noble metal (Pd) by galvanic displacement without applying potential. In one cell approach, the concentration ratio of sacrificial metal and noble metal and potential set is carefully set in order to deposit pure noble metal layer. Therefore, precise control of potential and metal concentration is important to execute successful SLRR which prevent Cu incorporation and Pd overpotential deposition upon Cu UPD formation.In this study, pure Pd nanofilm was formed on Au substrate using Cu sacrificial metal by SLRR protocol. Effort of minimizing Cu incorporation was conducted by controlling Pd ion concentration, potential , open circuit potential condition and adding additive. Pd film was characterized by XPS, AFM and open circuit potential was analyzed by potentiostat. By controlling Pd deposition condition, pure Pd film was successfully formed. KEYWORDS Palladium, one-cell, nanofilm, SLRR, Cu UPD

Impact of LiF Particle Morphology on Overpotential and Structure of Li Metal Deposition

It has been widely suggested in literature that a lithium fluoride (LiF)-rich solid electrolyte interphase (SEI) affects Coulombic efficiency (CE) of the Li metal anode used with liquid electrolytes. Yet, the influence of LiF on Li metal deposition has been challenging to examine. Herein, we developed a method to synthesize LiF nanoscale particles with tunable sizes (30–300 nm) on Cu electrodes by electrochemical reduction of fluorinated gases under controlled discharge rates and capacities. The impact of LiF nanoparticles on overpotential and morphology of Li deposition was further studied in a conventional carbonate electrolyte. By cyclic voltammetry, Li plating overpotentials exhibit a clear correlation with the total surface area of LiF particles. Additionally, Li metal deposits (10 μAh cm−2) nucleated under galvanostatic conditions (0.5 mA cm−2) on Cu/LiF showed increasing feature sizes with a lower average LiF particle size and higher coverage of LiF. However, no significant improvement in CE was observed for LiF-coated Cu. Our findings provide evidence that a particle-based mode of SEI fluorination can influence early-stage Li nucleation to a modest degree, and this effect is maximized when LiF is uniformly and densely distributed. However, sparser and larger LiF have vanishing or even detrimental effect on cycling performance.

Depolarization of Cu Electrodeposition in the Presence of Ag: A Cyclic-Voltammetry Study

During our investigation of Cu-Ag alloy electrodeposition from acidic sulfate bath, peculiar behavior of Cu reduction was found in the CV profiles when the Cu deposition overpotential is very small. An early Cu(II) reduction peak, which is revealed to be a full reduction of Cu(II) to Cu(0) based on the EQCM-CV measurement, was observed in addition to the main Cu(II)/Cu(0) deposition peak. To our surprise, this early Cu deposition peak occurs when the deposition bath contains Ag(I) cations, or the substrate contains Ag metals.EQCM-CV profile shows that the early Cu deposition peak is associated with a 65% deposition efficiency, slightly smaller than that of the main Cu(II)/Cu(0) reduction peak (~78%). The amount of Cu deposited associated with the early Cu reduction peak is estimated based on the total charge associated with this peak. The early Cu reduction peak is associated with Cu deposit thicker than 3 nm, with the thickness increases with decreasing scan rate or increasing Ag(I) concentration in the electrolyte. Meanwhile, from the CV profiles, the early Cu reduction peak is associated with a Tafel slope ~30mV/dec. We hypothesize that by the catalytic effect of Ag, either in the substrate or in the initial deposit, on the intermediate reduction step of Cu(II)/Cu(I) causes the early Cu reduction peak by shifting rate determining step of Cu(II)/Cu(0) deposition from Cu(II)/Cu(I) to Cu(I)/Cu(0). Disclaimer: This work has been submitted at Electrochimica Acta (manuscript id: EA21-4167RR1), with title "Depolarization of Cu electrodeposition in the presence of Ag: a cyclic-voltammetry study". Figure attached is chosen from this manuscript. Figure. Cyclic voltammograms at electropolished Cu substrate from 0.3 M CuSO4 + 0.5 M H2SO4 (a) with or without 0.5 mM NaNO3, and (b) with 0-0.5 mM AgNO3. Figure 1

Robust 3D Copper Foam Functionalized with Gold Nanoparticles as Anode for High-Performance Potassium Metal Batteries.

As a possible anode for the next generation of electrochemical energy storage batteries, potassium metal has attracted a great deal of attention in recent years. However, potassium metal batteries suffer from poor stability and low coulombic efficiency due to unfavorable dendrite growth and severe volume expansion of potassium metal anodes during charge and discharge processes. Here, a strategy is developed to inhibit dendrite growth, reduce volume expansion and improve the stability of the potassium metal anode by using three-dimensional (3D) copper foam chemically loaded with a thin layer of uniform gold particles (Au/Cu) as the anode substrate. As the host of potassium deposition for forming K/Au/Cu foam anode, such a 3D copper foam with large specific surface area can reduce the potassium deposition current density. The gold particles on the Cu foam surface with a good affinity to potassium can reduce the potassium deposition overpotential, provide deposition sites and realize uniform and dense deposition. As a result, a stable cycle of more than 500 cycles is achieved by using such a K/Au/Cu foam anode. A full cell with K/Au/Cu foam anode and Prussian blue cathode delivers much better coulombic efficiency, cycle stability and low-temperature performance when compared to that without gold deposition anode (K/Cu). Both the experimental characterization for material structure/morphology/composition and theoretical DFT calculations are carried out for fundamental understanding of the performance enhancement mechanism. The main advantages of this 3D K/Au/Cu foam are its potassiophilicity and less volume expansion during charge/discharge processes, which can reduce or eliminate the potassium dendrite growth through forming favorable and stable solid electrolyte interface.

3D stress mapping reveals the origin of lithium-deposition heterogeneity in solid-state lithium-metal batteries

Solid-state lithium-metal batteries possess intrinsic advantages in terms of both safety and energy density. However, the fundamental origin of electrochemical lithium deposition heterogeneity in solid-state batteries is much less understood than that in lithium-metal batteries using a liquid electrolyte, partly due to the difficulties of directly mapping lithium-deposition reaction fronts and the associated changes in local stress of the solid-state electrolyte. Here, we trace the evolution of three-dimensional microscopic stress and demonstrate that the stress distribution is rather broad in a garnet solid-state electrolyte during processing and battery cycling using confocal Raman spectroscopy. We further discuss the effect of local stress variations on the overpotential of lithium deposition as the most likely origin of lithium-deposition heterogeneity in garnet systems. The ex situ stress-mapping tool developed in this work provides a strong basis for understanding the electromechanical effects, a prerequisite to fully unlock the potential of solid-state lithium-metal batteries. • A method for multi-dimensional microscopic stress mapping is established • Tensile regions are converted to compressive upon extended cycling • Local stress difference and lithium-deposition heterogeneity are quantitatively linked The microscopic correlation between mechanical stress and electrochemical lithium deposition remains elusive when studying the origin of lithium-deposition heterogeneity. Hu et al. gain insights with a newly developed 3D microscopic stress mapping method.

Reversible and homogenous zinc deposition enabled by in-situ grown Cu particles on expanded graphite for dendrite-free and flexible zinc metal anodes

The rapid development of wearable electronics has boosted the exploration of flexible and safe energy storage devices, such as zinc ion batteries or capacitors; and suppressing the dendrite growth for Zn anode is essential for enhancing their performance. Addressing this, we report a dendrite-free and flexible Zn metal anode (Zn@Cu-Ps/EG) that is based on expanded graphite (EG) decorated with in-situ formed copper particles (Cu-Ps). In this material, the Cu-Ps act as zincophilic seeds that reduce zinc nucleation overpotential, while the EG substrate induces epitaxial electrodeposition of zinc for suppressing dendrite growth. Moreover, the Cu-Ps nail the graphite nanosheets tightly and enhance the mechanical strength and flexibility of the Cu-Ps/EG composite. Consequently, the Zn@Cu-Ps/EG anode exhibits a low Zn deposition overpotential of 142.8 mV and superior cycling performance over 3000 h upon cycling at 10.0 mA cm−2 and 10.0 mAh cm−2. A flexible Zn-ion capacitor equipped with this anode delivers excellent cycling performance for over 1600 cycles at 1.0 A g−1 and stable power output at various bending statuses. This work provides a new approach for designing advanced flexible and dendrite-free Zn metal anodes for energy storage applications.

In-situ growth of iron nanoparticles on porous carbon nanofibers for structural high-performance lithium metal anode

Lithium metal anodes have attracted increasing attention in recent years. However, there are still significant challenges in the electrochemical cycle of lithium metals, including the growth of lithium dendrites, the formation of "dead lithium" layers, and unrestricted volume expansion. To solve these problems, using inexpensive acetylacetonate salt, polyacrylonitrile, and polymethyl methacrylate as raw materials, a 3D porous carbon nanofiber scaffold decorated with iron nanoparticles is reasonably designed by novel and unique in-situ growth method, without hazardous atmosphere, expensive catalyst deposition, and additional carbon sources. Notably, the obtained iron-doped 3D porous fibers can be used as lithium metal anode framework with low lithium deposition overpotential and long cycling stability under various current densities. The porous host structure can adapt to the inherent volume expansion and the transmission of lithium ions in the process of lithium plating/stripping, thereby improving the cycling stability. Density functional theory calculations indicate that carbon nanofibers decorated with Fe nanoparticles are more likely to absorb lithium atoms, resulting in more uniform lithium deposition. The present work provides a low-cost and scalable strategy for constructing 3D structural high-efficiency lithium metal anode, and opens new horizons for the research of lithium metal batteries and even other metal batteries.

Li+ Solvation Mediated Interfacial Kinetic of Alloying Matrix for Stable Li Anodes

Severe lithium (Li) dendrite growth caused by the uneven overpotential deposition is a formidable challenge for high energy density Li metal batteries (LMBs). Herein, we investigate a synergetic interfacial kinetic to regulate Li deposition behavior and stabilize Li metal anode. Through constructing Li alloying matrix with a bi‐functional silver (Ag)‐Li3N blended interface, fast Li+ conductivity and high Li affinity can be achieved simultaneously, resulting in both decreased Li nucleation and mass transfer‐controlled overpotentials. Beyond these properties, a more important feature is demonstrated herein; that is, the inward diffusion depth of the Li adatoms inside of the Ag site can be restricted by the Li+ solvation structure in a highly coordinating environment. The latter feature can ensure the durability of the operational Ag sites, thereby elongating the Li protection ability of the Ag‐Li3N interface greatly. This work provides a deep insight into the synergetic effect of functional alloying structure and Li+ solvation mediated interfacial kinetic on Li metal protection.

Simultaneously in-situ fabrication of lithium fluoride and sulfide enriched artificial solid electrolyte interface facilitates high stable lithium metal anode

Lithium (Li) metal has to overcome key performance flaws before it can be used as the anode material for the next generation Li+ batteries. One of its major issues is Li dendrite growth and detachment, which causes safety issues and low Coulombic efficiency for Li metal batteries. Constructing a stable solid electrolyte interface (SEI) is considered to be the most straightforward solution to the Li anode interface defects. Here, we develop a facile stratagem of 2-(Fluorosulphonyl)difluoroacetic acid-treated Li foil to obtain a Li metal anode coated by the lithium fluoride and sulfide enriched composite layer (LiF/sulfide enriched Li). The experimental and theoretical simulations demonstrate that the ideal artificial SEI can induce uniform Li+ distribution at the interface and effectively inhibit dendrite growth. As results, the LiF/sulfide enriched Li symmetrical cells exhibit excellent cycling stability and low Li deposition overpotential, which maintain a low overpotential of ∼ 10 mV for over 1000 h at 1 mA cm−2 in an ether electrolyte of DME/DOL + LiTFSI and steadily cycles for 350 h in a carbonate electrolyte of EC/EMC + LiPF6. Furthermore, full cells assembled with NCM811 and sulfur cathode exhibit enhanced cyclability. This facile and controllable stratagem provides a more practical possibility for modifying the Li metal anode.