In-situ formation of hierarchical solid-electrolyte interphase for ultra-long cycling of aqueous zinc-ion batteries

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low cost.However,zinc metal anodes face fatal dendrite growth and detrimental side reactions,which affect the cycle stability and practical application of zinc ion batteries.Here,an in-situ formed hierarchical solid-electrolyte interphase composed of InF3,In,and ZnF2 layers with outside-in orientation on the Zn anode(denoted as Zn@InF3)is developed by a sample InF3 coating.The inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn,is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+conductivity.Meanwhile,the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces,good chemical inactivity,and high hydrogen evolution overpotential.Besides,the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100%coulombic efficiency(CE).Furthermore,coupled with the MnO2 cathode,the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity(N/P)ratio of 2.8.

Artificial solid-electrolyte interface facilitating uniform Zn deposition by promoting chemical adsorption

Zn-air batteries are promising energy storage and conversion systems to replace the conventional lithiumbased ones.However,their applications have been greatly hindered by the formation of Zn dendrites and ZnO passivation layer on the Zn anodes.Herein,we report the fabrication of an artificial protective layer comprised of N-doped threedimensional hollow porous multi-nanochannel carbon fiber with well-dispersed TiO_(2) nanoparticles(HMCNF).The incorporated TiO;nanoparticles and N dopants improve the ion flux distribution and promote the surface adsorption,facilitating the interfacial pseudocapacitive behaviors during Zn deposition.The hierarchical architecture also induces homogenous electric field distribution at the anode/electrolyte interface.Accordingly,the deposition behavior of Zn is regulated,giving rise to enhanced utilization and rechargeability of Zn.When integrated in alkaline Zn-air batteries,the HMCNF-coated Zn anodes exhibit improved electrochemical performances relative to those with the bare Zn anodes,demonstrating a versatile strategy to boost energy storage of metal anodes through optimizing surface adsorption properties.

Enabling an Inorganic-Rich Interface via Cationic Surfactant for High-Performance Lithium Metal Batteries

An anion-rich electric double layer(EDL)region is favorable for fabricating an inorganic-rich solid-electrolyte interphase(SEI)towards stable lithium metal anode in ester electrolyte.Herein,cetyltrimethylammonium bromide(CTAB),a cationic surfactant,is adopted to draw more anions into EDL by ionic interactions that shield the repelling force on anions during lithium plating.In situ electrochemical surface-enhanced Raman spectroscopy results combined with molecular dynamics simulations validate the enrichment of NO_(3)^(−)/FSI−anions in the EDL region due to the positively charged CTA^(+).In-depth analysis of SEI structure by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results confirmed the formation of the inorganic-rich SEI,which helps improve the kinetics of Li^(+)transfer,lower the charge transfer activation energy,and homogenize Li deposition.As a result,the Li||Li symmetric cell in the designed electrolyte displays a prolongated cycling time from 500 to 1300 h compared to that in the blank electrolyte at 0.5 mA cm^(-2) with a capacity of 1 mAh cm^(-2).Moreover,Li||LiFePO_(4) and Li||LiCoO_(2) with a high cathode mass loading of>10 mg cm^(-2) can be stably cycled over 180 cycles.

Achieving stable K-storage performance of carbon sphere-confined Sb via electrolyte regulation

Potassium-ion batteries(PIBs)have been considered as one of the most promising alternatives to lithiumion batteries(LIBs)in view of their competitive energy density with significantly reduced product cost.Moreover,alloy-type materials are expected as a high-performance anode of PIBs thanks to their intrinsic chemical stability as well as high theoretical specific capacity.Unfortunately,the serious incompatibility between alloy-type active materials and electrolytes,especially for the formation of unstable solidelectrolyte interfacial(SEI)films,often leads to insufficient cycle life.Herein,the formation mechanism of SEI films in the K-storage systems based on carbon sphere confined Sb anode(Sb@CS)were investigated in commercially available electrolytes.Physical characterizations and theoretical calculation revealed that the solvents in the dilute electrolyte of 0.8 M KPF_(6)/EC+DEC were excessively decomposed on the interface to generate unstable SEI and thus result in inferior K-storage stability.On the contrary,a salt-concentrated electrolyte(3 M KFSI/DME)can generate inorganic-dominated stable SEI due to the preferential decomposition of anions.As a result,the prepared Sb@CS in the matched 3 M KFSI/DME electrolyte delivered a high reversible capacity of 467.8 m A h g^(-1)after 100 cycles at 100 m A g^(-1),with a slow capacity decay of 0.19%per cycle from the 10th to the 100th cycle.These findings are of great significance for revealing the interfacial reaction between electrodes and electrolytes as well as improving the stability of Sb-based anode materials for PIBs.

Regulating Zn Deposition via an Artificial Solid–Electrolyte Interface with Aligned Dipoles for Long Life Zn Anode

Aqueous zinc ion batteries show prospects for next-generation renewable energy storage devices.However,the practical applications have been limited by the issues derived from Zn anode.As one of serious problems,Zn dendrite growth caused from the uncontrollable Zn deposition is unfavorable.Herein,with the aim to regulate Zn deposition,an artificial solid–electrolyte interface is subtly engineered with a perovskite type material,BaTiO3,which can be polarized,and its polarization could be switched under the external electric field.Resulting from the aligned dipole in BaTiO3 layer,zinc ions could move in order during cycling process.Regulated Zn migration at the anode/electrolyte interface contributes to the even Zn stripping/plating and confined Zn dendrite growth.As a result,the reversible Zn plating/stripping processes for over 2000 h have been achieved at 1 mA cm^(−2) with capacity of 1 mAh cm−2.Furthermore,this anode endowing the electric dipoles shows enhanced cycling stability for aqueous Zn-MnO2 batteries.The battery can deliver nearly 100%Coulombic efficiency at 2 Ag^(−1) after 300 cycles.

An interface-reconstruction effect for rechargeable aluminum battery in ionic liquid electrolyte to enhance cycling performances

Aluminum(Al) metal has been regarded as a promising anode for rechargeable batteries because of its natural abundance and high theoretical specific capacity. However, rechargeable aluminum batteries(RABs) using A1 metal as anode display poor cycling performances owing to interface problems between anode and electrolyte. The solid-electrolyte interphase(SEI) layer on the anode has been confirmed to be essential for improving cycling performances of rechargeable batteries. Therefore, we immerse the Al metal in ionic liquid electrolyte for some time before it is used as anode to remove the passive film and expose fresh Al to the electrolyte. Then the reactions of exposed Al, acid, oxygen and water in electrolyte are occurred to form an SEI layer in the cycle. Al/electrolyte/V_2 O_5 full batteries with the thin, uniform and stable SEI layer on Al metal anode perform high discharge capacity and coulombic efficiency(CE). This work illustrates that an SEI layer is formed on Al metal anode in the cycle using a simple and effective pretreatment process and results in superior cycling performances for RABs.

Multifunctional interfacial and structural anode for dendrite-free lithium metal-based batteries

Lithium(Li)metal is considered as the candidate for the next generation of Li metal battery(LMB)anodes due to its high capacity and the lowest potential,which is expected to meet the requirements of energy storage devices.Unfortunately,the uncontrollable growth of Li dendrites during the charge/discharge process,as well as the resulting problems of poor cycling stability,low coulomb efficiency and safety risk,has restricted the commercialization of Li anode.Herein,an in-situ interfacial film containing three-dimensional(3D)rod-like micron-structure silver(Ag)is constructed on the surface of the Li metal.Due to the 3D rod-like micron-structure used to homogenize the distribution of current density,achieving uniform nucleation and growth of electrodeposited Li,the produced Li-Ag alloy was employed to restrain the formation of“dead”Li and the in-situ formed LiNO_(3) was utilized to facilitate the stability of solid-electrolyte interface(SEI)film,so the growth of dendritic Li is suppressed via the synergistic effect of structure and surface chemistry regulation.The obtained Li anode can achieve cycling stability at a high current density of 10 mA/cm^(2).This work considers multiaspect factors inducing uniform Li electrodeposition,and provides new insights for the commercialization of LMB.

Size effect of Si particles on the electrochemical performances of Si/C composite anodes

A series of Si/C composites were fabricated based on pitch and Si powders with particle sizes of 30, 100, 500, and 3000 nm. The size effects of the Si particles in the Si/C composites were investigated for lithium-ion battery anodes. The nanoscale Si and Si/C composites exhibited good capacity retentions. Scanning electron microscopy showed that exterior and interior cracks emerging owing to volume expansion as well as parasitic reactions with the electrolyte could well explain the performance failure.

Recent advances in “water in salt” electrolytes for aqueous rechargeable monovalent-ion(Li^(+), Na^(+), K^(+)) batteries

Aqueous rechargeable batteries have attracted enormous attention owning to their intrinsic characteristics of non-flammability, low cost, and the superior ionic conductivity of the aqueous electrolyte.However, the narrow electrochemical stability window(1.23 V), imposed by hydrogen and oxygen evolution, constrains the overall energy density of batteries. The revolutionary "water-in-salt” electrolytes considerably expand the electrochemical stability window to 3 or even 4 volts, giving rise to a new series of high-voltage aqueous metal-ion chemistries. Herein, the recent advances in "water-in-salt” electrolytes for aqueous monovalent-ion(Li^(+), Na^(+), K^(+)) rechargeable batteries have been systematically reviewed. Meanwhile, the corresponding reaction mechanisms, electrochemical performances and the existing challenges and opportunities are also highlighted.

A robust interphase via in-situ pre-reconfiguring lithium anode surface for long-term lithium-oxygen batteries

Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.

Regulating interfacial stability of SiO_(x) anode with fluoride-abundant solid–electrolyte interphase by fluorine-functionalized additive

Silicon oxide(SiO_(x))has received remarkable attention as a next-generation battery material;however,the sudden decrease in the cycling retention constitutes a significant challenge in facilitating its application.Tris(2,2,2-trifluoroethyl)phosphite(TTFP),which can control parasitic reactions such as the pulverization of SiO_(x)anode materials and electrolyte decomposition,has been proposed to improve the lifespan of the cell.The electrochemical reduction of TTFP results in solid-electrolyte interphase(SEI)layers that are mainly composed of LiF,which occur at a higher potential than the working potential of the SiO_(x)anode and carbonate-based solvents.The electrolyte with TTFP exhibited a substantial improvement in cycling retention after 100 cycles,whereas the standard electrolyte showed acutely decreased retention.The thickness of the SiO_(x)anode with TTFP also changed only slightly without any considerable delamination spots,whereas the SiO_(x)anode without TTFP was prominently deformed by an enormous volume expansion with several internal cracks.The cycled SiO_(x)anode with TTFP exhibited less increase in resistance after cycling than that in the absence of TTFP,in addition to fewer decomposition adducts in corresponding X-ray photoelectron spectroscopy(XPS)analyses between the cycled SiO_(x)anodes.These results demonstrate that TTFP formed SEI layers at the SiO_(x)interface,which substantially reduced the pulverization of the SiO_(x)anode materials;in addition,electrolyte decomposition at the interface decreased,which led to improved cycling retention.

A promising solution for highly reversible zinc metal anode chemistry:Functional gradient interphase

Rechargeable zinc(Zn)metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase(SEI).Although the current strategies assist in suppressing dendritic Zn growth,it is still a challenge to obtain the operation-stability of Zn anode with high Coulombic efficiency(CE)required to implement a sustainable and long-cycling life of Zn metal batteries.In this perspective,we summarize the advantages of the functional gradient interphase(FGI)and try to fundamentally understand the transport behaviors of Zn ions,based on recently an article understanding Zn chemistry.The correlation between the function-orientated design of gradient interphase and key challenges of Zn metal anodes in accelerating Zn2+transport kinetics,improving electrode reversibility,and inhibiting Zn dendrite growth and side reactions was particularly emphasized.Finally,the rational design and innovative directions are provided for the development and application of functional gradient interphase in rechargeable Zn metal battery systems.

Tailoring alloy-reaction-induced semi-coherent interface to guide sodium nucleation and growth for long-term anode-less sodium-metal batteries

Sodium metal batteries are emerging as promising energy storage technologies owing to their high-energy density and rich resources.However,the challenge of achieving continuous operation at high areal capacity hinders the application of this system.Here,a robust two-dimensional tin/sodium‒tin alloy interface was introduced onto an Al substrate as an anode via an industrial electroplating strategy.Unlike the widely accepted in situ formation of Na15Sn4 alloys,the formation of Na_(9)Sn_(4)alloys results in a semi-coherent interface with sodium due to low lattice mismatch(20.84%),which alleviates the lattice stress of sodium deposition and induces subsequent dense sodium deposition under high areal capacity.In addition,the strong interaction of Sn with anions allows more PF6−to preferentially participate in the interfacial solvation structure,thereby facilitating the formation of a thin(10 nm)NaF-rich solid electrolyte interface.Therefore,the substrate can withstand a high areal capacity of 5 mA h cm^(-2),exhibiting a high average Coulombic efficiency of 99.7%.The full battery exhibits long-term cycling performance(600 cycles)with a low decay rate of 0.0018%per cycle at 60 mA g^(-1).

Activation mechanism of conventional electrolytes with amine solvents:Species evolution and hydride-containing interphase formation

Rechargeable magnesium(Mg)-metal batteries have brought great expect to overcome the safety and energy density concerns of typical lithium-ion batteries.However,interracial passivation of the Mgmetal anode impairs the reversible Mg plating/stripping chemistries,resulting in low Coulombic efficiency and large overpotential.In this work,a facile isobutylamine(IBA)-assisted activation strategy has been proposed and the fundamental mechanism has been unveiled in a specific way of evolving active species and forming MgH_(2)-based solid-electrolyte interphase.After introducing IBA into a typical electrolyte of magnesium bis(trifluoromethanesulfo nyl) imide(Mg(TFSI)_(2)) in diglyme(G2) solvents,electrolyte species of [Mg^(2+)(IBA)5]^(2+) and protonated amine-based cations of [(IBA)H]^(+) have been detected by nuclear magnetic resonance and mass spectra.This not only indicates direct solvation of IBA toward Mg^(2+)but also suggests its ionization,which is central to mitigating the decomposition of G2 and TFSI anions by forming neutrally charged [(IBAH^(+))(TFSI^(-))]~0 and other complex ions.A series of experiments,including cryogenic-electron microscopy,D_(2)O titration-mass spectra,and time of flight secondary ion mass spectrometry results,reveal a thin,non-passivated,and MgH_(2)-containing interphase on the Mg-metal anode.Besides,uniform and dendrite-free Mg electrodeposits have been revealed in composite electrolytes.Benefiting from the activation effects of IBA,the composite electrolyte displays superior electrochemical performance(overpotential is approximately 0.16 V versus 2.00 V for conventional electrolyte;Coulombic efficiency is above 90% versus <10% for conventional electrolyte).This work offers a fresh direction to advanced electrolyte design for next-generation rechargeable batteries.

Interfacial fusion-enhanced 11 μm-thick gel polymer electrolyte for high-performance lithium metal batteries

In the pursuit of ultrathin polymer electrolyte(<20 μm) for lithium metal batteries, achieving a balance between mechanical strength and interfacial stability is crucial for the longevity of the electrolytes.Herein, 11 μm-thick gel polymer electrolyte is designed via an integrated electrode/electrolyte structure supported by lithium metal anode. Benefiting from an exemplary superiority of excellent mechanical property, high ionic conductivity, and robust interfacial adhesion, the in-situ formed polymer electrolyte reinforced by titanosiloxane networks(ISPTS) embodies multifunctional roles of physical barrier, ionic carrier, and artificial protective layer at the interface. The potent interfacial interactions foster a seamless fusion of the electrode/electrolyte interfaces and enable continuous ion transport. Moreover, the built-in ISPTS electrolyte participates in the formation of gradient solid-electrolyte interphase(SEI) layer, which enhances the SEI's structural integrity against the strain induced by volume fluctuations of lithium anode.Consequently, the resultant 11 μm-thick ISPTS electrolyte enables lithium symmetric cells with cycling stability over 600 h and LiFePO_(4) cells with remarkable capacity retention of 96.6% after 800 cycles.This study provides a new avenue for designing ultrathin polymer electrolytes towards stable, safe,and high-energy–density lithium metal batteries.

Li-MOF-based ions regulator enabling fast-charging and dendrite-free lithium metal anode

Li metal has been regarded as the holy grail for the next-generation Li-ion battery.Li dendrites issues,however,impede its practical application.In general,prolonging the sand time of Li nucleation and regulating homogeneous Li^(+) flux are effective approaches to suppress the dendrites formation and growth.Regarding this view,a functional polypropylene (PP) separator is developed to regulate ion transportation via a newly designed Li-based metal-organic framework (Li-MOF) coating.The Li-MOF crystallizes in the orthorhombic space group P212121 and features a double-walled three-dimensional (3D) structure with 1D channels.The well-defined intrinsic nanochannels of Li-MOF and the steric-hinerance effect both restrict free migration of anions,contributing to a high Li^(+) transference number of 0.65,which improve the Sand time of Li nucleation.Meanwhile,the Li-MOF coating with uniform porous structure promotes homogeneous Li^(+) flux at the surface of Li metal.Furthermore,the Li-MOF coating layer helps to build solid-electrolyte interphase (SEI) layer that comprises of inorganic Li F and Li_(3)N,which further prohibits the dendrites growth.Consequently,a highly stable Li plating/stripping cycling for over 1000 h is achieved.The functional separator also enables high-performance full lithium metal cells,the high-rate and long-stable cycling performance of Li Ni_(0.8)Mn_(0.1)Co_(0.1)(NMC811)-Li and Li Co O_(2)(LCO)-Li cells further demonstrate the feasibility of this concept.

A review on the development of electrolytes for lithiumbased batteries for low temperature applications

The aerospace industry relies heavily on lithium-ion batteries in instrumentation such as satellites and land rovers.This equipment is exposed to extremely low temperatures in space or on the Martian surface.The extremely low temperatures affect the discharge characteristics of the battery and decrease its available working capacity.Various solvents,cosolvents,additives,and salts have been researched to fine tune the conductivity,solvation,and solid-electrolyte interface forming properties of the electrolytes.Several different resistive phenomena have been investigated to precisely determine the most limiting steps during charge and discharge at low temperatures.Longer mission lifespans as well as self-reliance on the chemistry are now highly desirable to allow low temperature performance rather than rely on external heating components.As Martian rovers are equipped with greater instrumentation and demands for greater energy storage rise,new materials also need to be adopted involving next generation lithiumion chemistry to increase available capacity.With these objectives in mind,tailoring of the electrolyte with highercapacity materials such as lithium metal and silicon anodes at low temperatures is of high priority.This review paper highlights the progression of electrolyte research for low temperature performance of lithium-ion batteries over the previous several decades.

On the bramble way to Mg metal anodes in secondary Mg ion batteries

As a prospective alternative to lithium-ion batteries,rechargeable magnesium metal batteries(RMBs)have many unparalleled advantages,including direct use of Mg metal as the electrode;large nature abundance;intrinsically safe merits;high theoretical volumetric capacity.Nonetheless,there exist a large number of challenges on electrodes for their applications.Among them,surface passivation,uneven deposition/dissolution,and corrosion are critical issues that severely hinder the development of Mg anodes in RMBs.This review gives a specific comprehensive,and in-depth summary of mechanisms relative to these problems.Subsequently,it displays the protection progresses of the Mg metal anode via three-dimensional host nanostructure fabrication,Mg alloys anode design,current collector modification,artificial solid-electrolyte interphase construction,and electrolyte optimization.Finally,future perspectives and outlooks in developing the other blossom of these strategies for rechargeable Mg batteries are also discussed.This overview provides significant guidance for designing and fabricating high-performance Mg metal anodes in secondary Mg batteries and boosting their commercial applications.

Superior plating/stripping performance through constructing an artificial interphase layer on metallic Mg anode

Rechargeable magnesium batteries(RMBs)have attracted tremendous attention in energy storage ap-plications in term of high abundance,high specific capacity and remarkable safety of metallic magne-sium(Mg)anode.However,a serious passivation of Mg anode in the conventional electrolytes leads to extremely poor plating/stripping performance,further hindering its applications.Herein,we propose a convenient method to construct an artificial interphase layer on Mg anode by substitution and alloy-ing reactions between SbCl_(3) and Mg.This Sb-based artificial interphase layer containing mainly MgCl_(2) and Mg_(3) Sb_(2) endows the significantly improved interfacial kinetics and electrochemical performance of Mg anode.The overpotential of Mg plating/stripping in conventional Mg(TFSI)2/DME electrolytes is vastly reduced from over 2 V to 0.25-0.3 V.Combining experiments and calculations,we demonstrate that un-der the uniform distribution of MgCl_(2) and Mg_(3) Sb_(2),an electric field with a favorable potential gradient is formed on the anode surface,which enables swift Mg^(2+)migration.Meanwhile,this layer can inhibit the decomposition of electrolytes to protect anode.This work provides an in-depth exploration of the artificial solid-electrolyte interface(SEI)construction,and a more achievable and safe path to realize the application of metallic Mg anode in RMBs.

Electrolyte and interphase engineering through solvation structure regulation for stable lithium metal batteries

Lithium metal batteries(LMBs)are considered to be one of the most promising high-energy-density battery systems.However,their practical application in carbonate electrolytes is hampered by lithium dendrite growth,resulting in short cycle life.Herein,an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO3 using trimethyl phosphate with a slightly higher donor number compared to NO_(3)^(-)as a solubilizer.This not only allows the formaion of Li^(+)-coordinated NO3 but also achieves the regulation of electrolyte solvation structures,leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes.As a result,high Coulombic efficiency of 99.1%and stable plating/stripping cycling of Li metal anode in LilCu cells were realized.Furthermore,excellent performance was also demonstrated in Li||LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)(NCM83)full cells and Cul/NCM83 anodefree cells using high mass-loading cathodes.This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.