Interfacial modulation of bifunctional electrolyte additive engineering for dendrite-free and robust lithium metal anode

Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential.Unfortunately,safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries.In this study,methyl vinyl sulfone(MVS),a sulfone-based functional electrolyte additive,is used in an additive engineering strategy to control Lielectrolyte interactions and address the aforementioned problems.Li dendrite growth may be restricted,and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer.The electrochemical performance of an ethylene carbonate/dimethyl carbonate(EC/DMC)+1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability,maintaining a low overvoltage for over 750 h at 1 mA cm^(-2),and capacity of 1 mA h cm^(-2).Additionally,LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g^(-1).This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.

An ultrathin and robust single-ion conducting interfacial layer for dendrite-free lithium metal batteries

The practical application of rechargeable lithium metal batteries(LMBs) encounters significant challenges due to the notorious dendrite growth triggered by uneven Li deposition behaviors. In this work,a mechanically robust and single-ion-conducting interfacial layer, fulfilled by the strategic integration of flexible cellulose acetate(CA) matrix with rigid graphene oxide(GO) and Li F fillers(termed the CGL layer), is rationally devised to serve as a stabilizer for dendrite-free lithium(Li) metal batteries. The GCL film exhibits favorable mechanical properties with high modulus and flexibility that help to relieve interface fluctuations. More crucially, the electron-donating carbonyl groups(C=O) enriched in GCL foster a strengthened correlation with Li^(+), which availably aids the Li^(+)desolvation process and expedites facile Li^(+)mobility, yielding exceptional Li^(+) transference number of 0.87. Such single-ion conductive properties regulate rapid and uniform interfacial transport kinetics, mitigating the growth of Li dendrites and the decomposition of electrolytes. Consequently, stable Li anode with prolonged cycle stabilities and flat deposition morphologies are realized. The Li||LiFePO_(4) full cells with CGL protective layer render an outstanding cycling capability of 500 cycles at 3 C, and an ultrahigh capacity retention of 99.99% for over 220 cycles even under harsh conditions. This work affords valuable insights into the interfacial regulation for achieving high-performance LMBs.

High Areal Capacity and Long Cycle Life Flexible Mild Quasi-Solid-State Ag-Zn Battery with Dendrite-Free Anode

Silver-zinc(Ag-Zn)batteries are a promising battery system for flexible electronics owing to their high safety,high energy density,and stable output voltage.However,poor cycling performance,low areal capacity,and inferior flexibility limit the practical application of Ag-Zn batteries.Herein,we develop a flexible quasi-solid-state Ag-Zn battery system with superior performance by using mild electrolyte and binder-free electrodes.Copper foam current collector is introduced to impede the growth of Zn dendrite,and the structure of Ag cathode is engineered by electrodeposition and chloridization process to improve the areal capacity.This novel battery demonstrates a remarkable cycle retention of 90%for 200 cycles at 3 mA cm^(-2).More importantly,this binder-free battery can afford a high capacity of 3.5 mAh cm^(-2)at 3 mA cm^(-2),an outstanding power density of 2.42 mW cm^(-2),and a maximum energy density of 3.4 mWh cm^(-2).An energy management circuit is adopted to boost the output voltage of a single battery,which can power electronic ink display and Bluetooth temperature and humidity sensor.The developed battery can even operate under the extreme conditions,such as being bent and sealed in solid ice.This work offers a path for designing electrodes and electrolyte toward high-performance flexible Ag-Zn batteries.

Metal-Organic Framework Enabling Poly(Vinylidene Fluoride)-Based Polymer Electrolyte for Dendrite-Free and Long-Lifespan Sodium Metal Batteries

Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and,more importantly,cause internal short circuit and lead to thermal runaway and fire.Therefore,sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries(SMBs).Herein,a design concept for the incorporation of metal-organic framework(MOF)in polymer matrix(polyvinylidene fluoride-hexafluoropropylene)is practiced to prepare a novel gel polymer electrolyte(PH@MOF polymer-based electrolyte[GPE])and thus to achieve high-performance SMBs.The addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na^(+)but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction.A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm^(-2)with areal capacity of 5 mA h cm^(-2)is achieved by symmetric cells based on the resulted GPE while the Na_(3)V_(2)O_(2)(PO_(4))_(2)F@rGO(NVOPF)|PH@MOF|Nacell also displays impressive specific cycling capacity(113.3 mA h g^(-1)at 1 C)and rate capability with considerable capacity retention.

All-Climate Stretchable Dendrite-Free Zn-Ion Hybrid Supercapacitors Enabled by Hydrogel Electrolyte Engineering

Hybrid supercapacitors have shown great potentials to fulfill the demand of future diverse applications such as electric vehicles and portable/wearable electronics.In particular,aqueous zinc-ion hybrid supercapacitors(ZHSCs)have gained much attention due to their low-cost,high energy density,and environmental friendliness.Nevertheless,typical ZHSCs use Zn metal anode and normal liquid electrolyte,causing the dendrite issue,restricted working temperature,and inferior device flexibility.Herein,a novel flexible Zn-ion hybrid supercapacitor(FZHSC)is developed by using activated carbon(AC)anode,δ-MnO_(2) cathode,and innovative PVA-based gel electrolyte.In this design,heavy Zn anode and its dendrite issue are avoided and layered cathode with large interlayer spacing is employed.In addition,flexible electrodes are prepared and integrated with an anti-freezing,stretchable,and compressible hydrogel electrolyte,which is attained by simultaneously using glycerol additive and freezing/thawing technique to regulate the hydrogen bond and microstructure.The resulting FZHSC exhibits good rate capability,high energy density(47.86 Wh kg^(−1);3.94 mWh cm^(−3)),high power density(5.81 kW kg^(−1);480 mW cm^(−3)),and excellent cycling stability(~91%capacity retention after 30000 cycles).Furthermore,our FZHSC demonstrates outstanding flexibility with capacitance almost unchanged even after various continuous shape deformations.The hydrogel electrolyte still maintains high ionic conductivity at ultralow temperatures(≤−30℃),enabling the FZHSC cycled well,and powering electronic timer robustly within an all-climate temperature range of−30~80℃.This work highlights that the promising Zn metal-free aqueous ZHSCs can be designed with great multifunctionality for more practical application scenarios.

Manipulating Horizontal Zn Deposition with Graphene Interpenetrated Zn Hybrid Foils for Dendrite-Free Aqueous Zinc Ion Batteries

Aqueous zinc ion batteries(ZIBs)with intrinsic safety have great potentials in portable devices,but suffer from limited cycling life mainly caused by serious dendrite growth and unavoidable side reactions of Zn anodes.Herein,graphene interpenetrated Zn(GiZn)hybrid foils are developed for dendrite-free and long-term Zn anodes for high-performance ZIBs.The GiZn anode is prepared by interfacial assembly of reduced graphene oxide(rGO)on the skeletons of zinc foams,followed by mechanical compression into hybrid foils and drying process.The presence of the rGO nanosheets in the GiZn hybrid foils provides abundant zincophilic sites to induce horizontal Zn deposition for Zn metal anodes without the growth of dendrites.Meanwhile,the uniform distribution of rGO nanosheets endows the hybrid foils with superior conductivity and wetting ability with electrolytes for reduced interfacial resistances.As a result,GiZn-based symmetric cells exhibit a small voltage hysteresis of 30.4 mV and remarkable areal capacity of 30 mAh cm^(-2)at 0.5 mA cm^(-2).Further,GiZn anodes also enable the corresponding aqueous Zn||MnO_(2)batteries with high capacity of 168.5 mAh g^(-1)at 8 C,superior to the counterpart with pure Zn foil anodes(72.7 mAh g^(-1)).Therefore,GiZn hybrid foil anodes will shed light on the rational construction of 2D material-interpenetrated Zn hybrid foil anodes for high-performance ZIBs.

Understanding Dual-Polar Group Functionalized COFs for Accelerating Li-Ion Transport and Dendrite-Free Deposition in Lithium Metal Anodes

Lithium metal batteries(LMBs)have attracted wide attentions because of their high theoretical specific capacity and low electrochemical potential.However,the growth of lithium dendrites seriously affects the practical application of LMBs.Thus,the lithium-philic carbonyl and carboxy dualgroup-modified covalent organic framework(COF-COOH)is designed to coat the polypropylene(PP)separator(COF-COOH@PP separator),realizing the regulation of ion transport and uniform lithium deposition.The plentiful and negative charge sites in the COF-COOH can suppress the diffusion of the freely movable lithium salt anion by the electrostatic interaction.Density functional theory(DFT)calculations demonstrate that the COF-COOH possesses the function of anchoring anion and desolvation.Consequently,the Li^(+)transference number(0.7),ion conductivity(0.64 mS cm^(-1)),and desolvating of Li^(+)are obviously improved by using the COF-COOH@PP separator.The modified Li-Li symmetric battery delivers stable cycle for more than 1000 h and lower voltage hysteresis(0.02 V).This dendrite-free deposition strategy holds great promise for practical application of Li metal anodes.

Boosting Zn^(2+)kinetics via the multifunctional pre-desolvation interface for dendrite-free Zn anodes

Aqueous zinc ion batteries(AZIBs)are an advanced secondary battery technology to supplement lithiumion batteries.It has been widely concerned and developed recently based on the element abundance and safety advantages.However,AZIBs still suffer from serious problems such as dendrites Zn,hydrogen evolution corrosion,and surface passivation,which hinder the further commercial application of AZIBs.Herein,an in-situ ZnCr_(2)O_(4)(ZCO)interface endows AZIBs with dendrite-free and ultra-low polarization by realizing Zn^(2+)pre-desolvation,constraining H2O-induced corrosio n,and boosting Zn^(2+)transport/deposition kinetics.The ZCO@Zn anode harvests an ultrahigh cumulative capacity of~20000 mA h cm^(-2)(cycle time:over 4000 h)at a high current density of 10 mA cm^(-2),indicating excellent reversibility of Zn deposition,Such superior performance is among the best cyclability in AZIBs.Moreover,the multifunctional ZCO interface improves the Coulombic efficiency(CE)to 99.7%for more than 2600 cycles.The outstanding electrochemical performance is also verified by the long-term cycle stability of ZCO@Zn//α-MnO_(2) full cells.Notably,the as-proposed method is efficient and low-cost enough to enable mass production.This work provides new insights into the uniform Zn electrodeposition at the scale of interfacial Zn^(2+)predesolvation and kinetics improvement.

Simultaneous realization of high sulfur utilization and lithium dendrite-free via dual-effect kinetic regulation strategy toward lithium-sulfur batteries

With the high theoretical specific capacity and energy density,lithium-sulfur batteries(LSBs)have been intensively studied as promising candidates for energy storage devices.However,LSBs are largely hindered by inferior sulfur utilization and uncontrollable dendritic growth.Herein,a hierarchical functionalization strategy of stepwise catalytic-adsorption-conversion for sulfur species via the synergetic of the efficiently catalytic host cathode and light multifunctional interlayer has been proposed to concurrently address the issues arising on the dual sides of the LSBs.The multi-layer SnS_(2) micro-flowers embedded into the natural three-dimensional(3D)interconnected carbonized bacterial cellulose(CBC)nanofibers are fabricated as the sulfur host that provides numerous catalytic sites for the rapid catalytic conversion of sulfur species.Moreover,the distinctive CBC-based SnO_(2)-SnS_(2) heterostructure network accompanied high conductive carbon nanofibers as the multifunctional interlayer promotes the rapid anchoringdiffusion-conversion of lithium polysulfides,Li^(+)flux redistribution,and uniform Li deposition.LSBs equipped with our strategy exhibit a high reversible capacity of 1361.5 m A h g^(-1)at 0.2 C and superior cycling stability with an ultra-low capacity fading of 0.031%per cycle in 1000 cycles at 1.5 C and 0.046%at 3 C.A favorable specific capacity of 859.5 m A h g^(-1)at 0.3 C is achieved with a high sulfur mass loading of 5.2 mg cm^(-2),highlighting the potential of practical application.The rational design in this work can provide a feasible solution for high-performance LSBs and promote the development of advanced energy storage devices.

A Janus separator towards dendrite-free and stable zinc anodes for long-duration aqueous zinc ion batteries

Critical issues of Zn anodes including undesirable dendrites formation and parasitic reactions severely limit the reversibility and cyclability of Zn anodes.To address these issues,a functional Janus separator with the structure of a mechanically strong sulfonated poly(arylene ether sulfone)(SPAES)dense layer composited on a porous glass fiber(GF)substrate is designed.The SPAES dense layer that faces the Zn anode containing abundant sulfonic acid groups effectively promotes the desolvation process of hydrated Zn ions,guides uniform Zn ion transfer,and blocks anions and water,contributing to dendrite-free and highly reversible Zn plating/stripping cycles,while the porous GF substrate retains high electrolyte uptake.As a result,the Zn symmetric cell with the Janus separator demonstrates an ultralong cycling lifespan of over 2000 h at the areal capacity of 1 m A h cm^(-2),which is 23-fold superior to that with a pristine glass fiber separator(<90 h).More impressively,the as-prepared Janus separator enables outstanding rate performance and excellent cycling stability of full Zn ion batteries with diverse cathode materials.For instance,when paired with the V_2O_(5)cathode,the full battery with a Janus separator attains an ultrahigh initial specific capacity of 416.3 m A h g^(-1)and capacity retention of 60%over 450 cycles at 1 A g^(-1),exceeding that with a glass fiber separator.Hence,this work provides a facile yet effective approach to mitigating the dendrites formation and ameliorating the parasitic reactions of Zn metal anodes for high-performance Zn ion batteries.

Recent Progress and Prospects on Dendrite-free Engineerings for Aqueous Zinc Metal Anodes

Rechargeable zinc-ion batteries with mild aqueous electrolytes are one of the most promising systems for large-scale energy storage as a result of their inherent safety,low cost,environmental-friendliness,and acceptable energy density.However,zinc metal anodes always suffer from unwanted dendrite growth,leading to low Coulombic efficiency and poor cycle stability and during the repeated plating/stripping processes,which substantially restrict their further development and application.To solve these critical issues,a lot of research works have been dedicated to overcoming the drawbacks associated with zinc metal anodes.In this overview,the working mechanisms and existing issues of the zinc metal anodes are first briefly outlined.Moreover,we look into the ongoing processes of the different strategies for achieving highly stable and dendrite-free zinc metal anodes,including crystal engineering,structural engineering,coating engineering,electrolyte engineering,and separator engineering.Finally,some challenges being faced and prospects in this field are provided,together with guiding significant research directions in the future.

3D Free-Standing Carbon Nanofibers Modified by Lithiophilic Metals Enabling Dendrite-Free Anodes for Li Metal Batteries

Li metal with high-energy density is considered as the most promising anode for the next-generation rechargeable Li metal batteries;however,the growth of Li dendrites seriously hinders its practical application.Herein,3D free-standing carbon nanofibers modified by lithiophilic metal particles(CNF/Me,Me=Sn,Fe,Co)are obtained in situ by the electrospinning method.Benefiting from the lithophilicity,the CNF/Me composite may effectively prevent the formation of Li dendrites in the Li metal batteries.The optimized CNF/Sn–Li composite electrode exhibits a stable cycle life of over 2350 h during Li plating/stripping.When matched with typical commercial LiFePO_(4)(LFP)cathode,the LFP//CNF/Sn–Li full cell presents a high initial discharge specific capacity of 139 mAh g^(−1)at 1 C,which remains at 146 mAh g^(−1)after 400 cycles.When another state-of-the-art commercial LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM(811))cathode is used,the assembled NCM//CNF/Sn–Li full cell shows a large initial specific discharge capacity of 206 mAh g^(−1)at substantially enhanced 10 C,which keeps at the good capacity of 99 mAh g^(−1)after 300 cycles.These results are greatly superior to the counterparts with Li as the anodes,indicating the great potential for practical utilization of the advanced CNF/Sn–Li electrode.

Mesoporous Graphene Hosts for Dendrite-Free Lithium Metal Anode in Working Rechargeable Batteries

Lithium(Li) metal anode has received extensive attentions due to its ultrahigh theoretical capacity and the most negative electrode potential. However, dendrite growth severely impedes the practical applications of the Li metal anode in rechargeable batteries. In this contribution, a mesoporous graphene with a high specific surface area was synthesized to host the Li metal anode. The mesoporous graphene host(MGH) has a high specific surface area(2090 m^2/g), which affords free space and an interconnected conductive pathway for Li plating and stripping, thus alleviating the volume variation and reducing the generation of dead Li during repeated cycles. More importantly, the high specific surface area of MGH efficiently reduces the local current density of the electrode, which favors a uniform Li nucleation and plating behavior, rendering a dendritefree deposition morphology at a low overpotential. These factors synergistically boost the Li utilization(90.1% vs. 70.1% for Cu foil) and life span(150 cycles vs. 100 cycles for Cu foil) with a low polarization of MGH electrode at an ultrahigh current of 15.0 mA/cm^2. The as-prepared MGH can provide fresh insights into the electrode design of the Li metal anode operating at high rates.

Engineering Sodium Metal Anode with Sodiophilic Bismuthide Penetration for Dendrite-Free and High-Rate Sodium-Ion Battery

Sodium(Na)metal batteries with a high volumetric energy density that can be operated at high rates are highly desirable.However,an uneven Na-ion migration in bulk Na anodes leads to localized deposition/dissolution of sodium during high-rate plating/stripping behaviors,followed by severe dendrite growth and loose stacking.Herein,we engineer the Na hybrid anode with sodiophilic Na_(3)Bi-penetration to develop the abundant phase-boundary ionic transport channels.Compared to intrinsic Na,the reduced adsorption energy and ion-diffusion barrier on Na_(3)Bi ensure even Na^(+)nucleation and rapid Na^(+)migration within the hybrid electrode,leading to uniform deposition and dissolution at high current densities.Furthermore,the bismuthide enables compact Na deposition within the sodiophilic framework during cycling,thus favoring a high volumetric capacity.Consequently,the obtained anode was endowed with a high current density(up to 5 mA∙cm^(−2)),high areal capacity(up to 5 mA∙h∙cm^(−2)),and long-term cycling stability(up to 2800 h at 2 mA∙cm^(−2)).

MXene-assisted polymer coating from aqueous monomer solution towards dendrite-free zinc anodes

Coating polymer on the surface is an effective way to realize functional modification of the materials for diverse applications,which has been proved to enhance the stability of metal anodes in batteries.However,given the limited operability of coating from polymer dispersions,it is imperative to develop simple aqueous-based strategies from monomers for versatile polymer coating.Herein,a Ti_(3)C_(2)Tx MXene-assisted approach is proposed to construct polymer coating on zinc metal surfaces directly from the aqueous solution of monomers in an ice bath.By combining a doctor-blading method with spontaneous polymerization of monomers on the substrates at room temperature,a uniform,adhesive,and versatile coating layer assisted by a small amount of MXene is produced in one step.Additionally,MXene nanosheets serve as nanofillers to further enhance the mechanical strength and ionic conductivity of the polymer coating.Benefiting from good film formation and improved interfacial contact,the coated zinc anode exhibits a long cycling lifespan of over 1900 h.The assembled full cells show excellent cycling stability with a high capacity retention of 85.0%at 16 A g^(-1)over 2600 cycles.This work provides a simple and efficient way to produce polymer coatings directly from monomers,which may give new insights into design multifunctional polymer coatings for various applications.

Stable and dendrite-free Zn anode with artificial desolvation interface layer toward high-performance Zn-ion capacitor

Aqueous Zn-based energy storage devices possess tremendous advantages, such as low cost, high safety,and competitive energy density, due to employing a Zn metal anode and aqueous electrolyte. However,the cycling stability and rate ability of a Zn anode are hindered by Zn dendrite growth and sluggish ion transfer in the electrode/electrolyte interface. Herein, the interfacial properties of Zn anodes are improved through the introduction of a silver(Ag) protective layer, which facilitates uniform Zn deposition and regulates Zn ion transport. As a result, Ag-coated Zn anodes display stable cycling performance(600 h at 1 m A cm^(-2)) and low overpotential(150 mV at 50 mA cm^(-2)after 2000 cycles). The Ag layer in situ electrochemically converts into an AgZn_(3) layer and promotes Zn ion desolvation and threedimensional diffusion processes. Moreover, a Zn-ion capacitor assembled with an Ag-coated Zn anode and active carbon cathode shows a capable cycling lifespan and rate performance. This study provides a feasible strategy for constructing a stabilized and dendrite-free Zn anode for the development of high-performance Zn-based energy storage devices.

Sodiophilic and conductive carbon cloth guides sodium dendrite-free Na metal electrodeposition

Sodium metal battery(SMB)technology is one of the most promising candidates for next-generation rechargeable energy storage systems due to its high theoretical capacity and economical costeffectiveness.Unfortunately,its practical implementation is hindered by several challenges including short life-span and fast capacity decay,which is closely related to the uncontrollable generation of the sodium dendrites.Herein,a nitrogen and oxygen co-doped three-dimensional carbon cloth with hollow tubular fiber units was constructed as the host material for Na plating(Na@CC)to tackle these challenges.The obtained composite electrode can effectively reduce the nucleation overpotential of Na,guide the homogeneous Na^(+)flux,increase the kinetics of Na electrodeposition,lower the effective current density and eventually suppress the formation of electrochemically inactive Na dendrites.As a result,batteries built with the Na@CC composites exhibited stable long-term cycling stability.To gain an in-depth and comprehensive understanding of such phenomena,non-destructive and three-dimensional synchrotron X-ray tomography was employed to investigate the cycled batteries.Moreover,the COMSOL Multiphysics simulation was further employed to reveal the Na electrodeposition mechanisms.The current work not only showcases the feasibility of currently proposed sodiophilic 3 D Na@CC composite electrode but also provides fundamental insights into the underlying working mechanisms that govern its outstanding electrochemical performance.

An ion-released MgI_(2)-doped separator inducing a LiI-containing solid electrolyte interphase for dendrite-free Li metal anodes

Lithium metal batteries are among the strong contenders to satisfy the ever-increasing needs of energy storage systems,which however suffer from poor composition of the solid electrolyte interphase(SEI)layer and uncontrolled Li dendrites formation.In this regard,we report on the design of an ionreleased MgI_(2)-doped polyacrylonitrile(PAN)based nanofiber(MPANF)separator,which can lead to conducive SEI layer and dendrite-free Li anode.The combination of the lithophilic MgI_(2)nanoparticles with polarized PAN matrix comprehensively functions as a high-compatible interpenetrating network to homogenize ionic transportation and confront dendrite growth.The released I ions introduce the highion-conductivity LiI into SEI layer,which could induce the formation of favorable and protective interface layer in the early stage,as embodied in the enrichment of advantageous components such as LiN_(x)O_(y),Li_(2)O,LiF,and Li_(3)N.Profited from the high-affinity MPANF separator,the Li||Li symmetric cell achieves an ultralow voltage hysteresis of 46 mV with an extended lifespan of 580 h.And a prolonged lifetime of 590cycles with an enhanced specific capacity of 140.1 m Ah g^(-1)and the Coulombic efficiency of 96.2%at 1C can be obtained in full cells.This work may offer a facile and high-affinity alternative to traditional polymeric separators for high-performance and dendrite-free Li metal batteries.

In situ formation of lithiophilic Li_(22)Sn_(5) alloy and high Li-ion conductive Li_(2)S/Li_(2)Se via metal chalcogenide SnSSe for dendrite-free Li metal anodes

Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.

Oxygen vacancies with localized electrons direct a functionalized separator toward dendrite-free and high loading LiFePO_(4)for lithium metal batteries

The pursuit of high energy density has promoted the development of high-performance lithium metal batteries(LMBs).However,the underestimated but non-negligible dendrites of Li anode have been observed to shorten battery lifespan.Herein,a composite separator(TiO_(2-x)@PP),in which TiO_(2)with electron-localized oxygen vacancies(TiO_(2-x))is coated on a commercial PP separator,is fabricated to homogenize lithium ion transport and stabilize the lithium anode interface.With the utilization of TiO_(2-x)@PP separators,the symmetric lithium metal battery displays enhanced cycle stability over 800 h under a high current density of 8 m A cm^(-2).Moreover,the LMBs assembled with high-loading LiFePO_(4)(9.24 mg cm^(-2))deliver a stable cycling performance over 900 cycles at a rate of 0.5 C.Comprehensive theoretical studies based on density functional theory(DFT)further unveil the mechanism.The favorable TiO_(2-x)is beneficial for facilitating fast Li+migration and impeding anions transfer.In addressing the Li dendrite issues,the use of TiO_(2-x)@PP separator potentially provides a facile and attractive strategy for designing well-performing LMBs,which are expected to meet the application requirements of rechargeable batteries.