Stable and reversible zinc metal anode with fluorinated graphite nanosheets surface coating

A highly stable zinc metal anode modified with a fluorinated graphite nanosheets(FGNSs)coating was designed.The porous structure of the coating layer effectively hinders lateral mass transfer of Zn ions and suppresses dendrite growth.Moreover,the high electronegativity exhibited by fluorine atoms creates an almost superhydrophobic solid-liquid interface,thereby reducing the interaction between solvent water and the zinc substrate.Consequently,this leads to a significant inhibition of hydrogen evolution corrosion and other side reactions.The modified anode demonstrates exceptional cycling stability,as symmetric cells exhibit sustained cycling for over 1400 h at a current density of 5 mA/cm^(2).Moreover,the full cells with NH_(4)V_(4)O_(10)cathode exhibit an impressive capacity retention rate of 92.2%after undergoing 1000 cycles.

Regulating the inner Helmholtz plane structure at the electrolyte-electrode interface for highly reversible aqueous Zn batteries

The development of aqueous Zn batteries is limited by parasitic water reactions,corrosion,and dendrite growth.To address these challenges,an inner Helmholtz plane(IHP)regulation method is proposed by employing low-cost,non-toxic maltitol as the electrolyte additive.The preferential adsorption behavior of maltitol can expel the water from the inner Helmholtz plane,and thus hinder the immediate contact between Zn metal and H_(2)O.Meanwhile,strong interaction between maltitol and H_(2)O molecules can restrain the activity of H_(2)O.Besides,the"IHP adsorption effect"along with the low LUMO energy level of maltitol-CF_(3)SO_(3)^(-)can promote the in-situ formation of an organic-inorganic complex solid electrolyte interface(SEI)layer.As a result,the hydrogen/oxygen evolution side reaction,corrosion,and dendrites issues are effectively suppressed,thereby leading to highly reversible and dendrite-free Zn plating/stripping.The Zn‖I_(2)battery with hybrid electrolytes also demonstrates high electrochemical performance and ultralong cycling stability,showing a capacity retention of 75%over 20000 charge-discharge cycles at a large current density of 5 A g^(-1).In addition,the capacity of the device has almost no obvious decay over20000 cycles even at-30℃.This work offers a successful electrolyte regulation strategy via the IHP adsorption effect to design electrolytes for high-performance rechargeable Zn-ion batteries.

Dendrite‑Free and Stable Lithium Metal Battery Achieved by a Model of Stepwise Lithium Deposition and Stripping

The uncontrolled formation of lithium(Li)dendrites and the unnecessary consumption of electrolyte during the Li plating/stripping process have been major obstacles in developing safe and stable Li metal batteries.Herein,we report a cucumber-like lithiophilic composite skeleton(CLCS)fabricated through a facile oxidationimmersion-reduction method.The stepwise Li deposition and stripping,determined using in situ Raman spectra during the galvanostatic Li charging/discharging process,promote the formation of a dendrite-free Li metal anode.Furthermore,numerous pyridinic N,pyrrolic N,and CuxN sites with excellent lithiophilicity work synergistically to distribute Li ions and suppress the formation of Li dendrites.Owing to these advantages,cells based on CLCS exhibit a high Coulombic efficiency of 97.3%for 700 cycles and an improved lifespan of 2000 h for symmetric cells.The full cells assembled with LiFePO_(4)(LFP),SeS_(2) cathodes and CLCS@Li anodes demonstrate high capacities of 110.1 mAh g^(−1) after 600 cycles at 0.2 A g^(−1) in CLCS@Li|LFP and 491.8 mAh g^(−1) after 500 cycles at 1 A g^(−1) in CLCS@Li|SeS2.The unique design of CLCS may accelerate the application of Li metal anodes in commercial Li metal batteries.

Polyanionic hydrogel electrolyte enables reversible and durable Zn anode for efficient Zn-based energy storage

Aqueous Zn-ion energy storage systems,which are expected to be integrated into intelligent electronics as a secure power supply,suffer poor reversibility of Zn anodes,predominantly associated with dendritic growth and side reactions.This study introduces a polyanionic strategy to address these formidable issues by developing a hydrogel electrolyte(PACXHE)with carboxyl groups.Notably,the carboxyl groups within the hydrogel structure establish favorable channels to promote the transport of Zn^(2+)ions.They also expedite the desolvation of hydrated Zn^(2+)ions,leading to enhanced deposition kinetics.Additionally,these functional groups confine interfacial planar diffusion and promote preferential deposition along the(002)plane of Zn,enabling a smooth surface texture of the Zn anode.This multifaceted regulation successfully achieves the suppression of Zn dendrites and side reactions,thereby enhancing the electrochemical reversibility and service life during plating/stripping cycles.Therefore,such an electrolyte demonstrates a high average Coulombic efficiency of 97.7%for 500 cycles in the Zn‖Cu cell and exceptional cyclability with a duration of 480 h at 1 mA cm^(-2)/1 mA h cm^(-2)in the Zn‖Zn cell.Beyond that,the Zn-ion hybrid micro-capacitor employing PACXHE exhibits satisfactory cycling stability,energy density,and practicality for energy storage in flexible,intelligent electronics.The present polyanionic-based hydrogel strategy and the development of PACXHE represent significant advancements in the design of hydrogel electrolytes,paving the way for a more sustainable and efficient future in the energy storage field.

Tuning Lithiophilicity and Stability of 3D Conductive Scaffold via Covalent Ag-S Bond for High-Performance Lithium Metal Anode

Li metal anode holds great promise to realize high-energy battery systems.However,the safety issue and limited lifetime caused by the uncontrollable growth of Li dendrites hinder its commercial application.Herein,an interlayer-bridged 3D lithiophilic rGO-Ag-S-CNT composite is proposed to guide uniform and stable Li plating/stripping.The 3D lithiophilic rGO-Ag-S-CNT host is fabricated by incorporating Ag-modified reduced graphene oxide(rGO)with S-doped carbon nanotube(CNT),where the rGO and CNT are closely connected via robust Ag-S covalent bond.This strong Ag-S bond could enhance the structural stability and electrical connection between rGO and CNT,significantly improving the electrochemical kinetics and uniformity of current distribution.Moreover,density functional theory calculation indicates that the introduction of Ag-S bond could further boost the binding energy between Ag and Li,which promotes homogeneous Li nucleation and growth.Consequently,the rGO-Ag-S-CNT-based anode achieves a lower overpotential(7.3 mV at 0.5 mA cm^(−2)),higher Coulombic efficiency(98.1%at 0.5 mA cm^(−2)),and superior long cycling performance(over 500 cycles at 2 mA cm−2)as compared with the rGO-Ag-CNT-and rGO-CNT-based anodes.This work provides a universal avenue and guidance to build a robust Li metal host via constructing a strong covalent bond,effectively suppressing the Li dendrites growth to prompt the development of Li metal battery.

Heterogeneous electrolyte membranes enabling double-side stable interfaces for solid lithium batteries

The solid polymer electrolyte(SPE) is one of the most promising candidates for building solid lithium batteries with high energy density and safety due to its advantages of flexibility and light-weight.However,the conventional monolayered electrolytes usually exhibit unstable contacts with either high-voltage cathodes or Li-metal anodes during cell operation.Herein,heterogeneous dual-layered electrolyte membranes(HDEMs) consisting of the specific functional polymer matrixes united with the designed solid ceramic fillers are constructed to address the crucial issues of interfacial instability.The electrolyte layers composed of the high-conductivity and oxidation-resistance polyacrylonitrile(PAN) combined with Li_(0.33)La_(0.557)TiO_(3) nanofibers are in contact with the high-voltage cathodes,achieving the compatible interface between the cathodes and the electrolytes.Meanwhile,the electrolyte layers composed of the highstability and dendrite-resistance polyethylene oxide(PEO) with Li_(6.4)La_(3) Zr_(1.4)Ta_(0.6)O_(12) nanoparticles are in contact with the Li-metal anodes,aiming to suppress the dendrite growth,as well as avoid the passivation between the PAN and the Li-metal.Consequently,the solid LiNi_(0.6)Co_(0.2)Mn_(0.2)O2‖Li full cells based on the designed HDEMs show the good rate and cycling performance,i.e.the discharge capacity of 170.1 mAh g^(-1) with a capacity retention of 78.2% after 100 cycles at 0.1 C and 30℃.The results provide an effective strategy to construct the heterogeneous electrolyte membranes with double-side stable electrode/-electrolyte interfaces for the high-voltage and dendrite-free solid lithium batteries.

Sn-O dual-doped Li-argyrodite electrolytes with enhanced electrochemical performance

As a type of candidate for all-solid-state Li batteries,argyrodite solid electrolytes possess high ionic conductivity,but poor compatibility against Li metal.Here,we report novel Li_(6) PS_(5) I-based argyrodite sulfides with Sn-O dual doping,which is a powerful solution to comprehensively improve the performance of a material.The combination of O and Sn-aliovalent doping not only enables an improved ionic conductivity but more importantly realizes an intensively enhanced interfacial compatibility between argyrodite and Li metal and Li dendrite suppression capability.The assembled battery with Sn-O dual-doped electrolyte and Li anode demonstrates high capacity and decent cycling stability.Dual doping is thus believed to be an effective way to develop high performance sulfide solid electrolytes.

Fast Zn^(2+)mobility enabled by sucrose modified Zn^(2+)solvation structure for dendrite-free aqueous zinc battery

Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity.However,the safety concern on Zn anodes caused by uncontrolled Zn dendrite growth in aqueous electrolyte hinders their application.Herein,sucrose with multi-hydroxyl groups has been introduced into aqueous electrolyte to modify Zn^(2+)solvation environment and create a protection layer on Zn anode,thus effectively retarding the growth of zinc dendrites.Atomistic simulations and experiments confirm that sucrose molecules can enter into the solvation sheath of Zn^(2+),and the as-formed unique solvation structure enhances the mobility of Zn^(2+).Such fast Zn^(2+)kinetics in sucrose-modified electrolyte can successfully suppress the dendrite growth.With this sucrose-modified aqueous electrolyte,Zn/Zn symmetric cells present more stable cycle performance than those using pure aqueous electrolyte;Zn/C cells also deliver an impressive higher energy density of 129.7 Wh·kg^(−1)and improved stability,suggesting a great potential application of sucrose-modified electrolytes for future Zn batteries.

Multi-factor principle for electrolyte additive molecule design for facilitating the development of electrolyte chemistry

When I read the paper“Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries”from Prof.Jianmin Ma’s group,which was published in Science Bulletin(doi.org/10.1016/j.scib.2020.09.018),I felt excited as presented a multi-factor principle for applying potassium perfluorinated sulfonates to suppress the dendrite growth and protect the cathode from the viewpoint of electrolyte additives.The effects of these additives are revealed through experimental results,molecular dynamics simulations and first-principle calculations.Specifically,it involves the influence of additives on Li^(+)solvation structure,solid electrolyte interphase(SEI),Li growth and nucleation.Following the guidance of the multi-factor principle,every part of the additive molecule should be utilized to regulate electrolytes.This multifactor principle for electrolyte additive molecule design(EAMD)offers a unique insight on understanding the electrochemical behavior of iontype electrolyte additives on both the Li metal anode and high-voltage cathode.In these regards,I would be delighted to write a highlight for this innovative work and,hopefully,it may raise more interest in the areas of electrolyte additives.

Constructing a fluorinated interface layer enriched with Ge nanoparticles and Li-Ge alloy for stable lithium metal anodes

Lithium metal batteries(LMBs)based on metallic Li exhibit high energy density to be competent for advanced energy storage applications.However,the unstable solid electrolyte interphase(SEI)layer due to continuous decomposition of electrolytes,and the attendant problem of Li dendrite growth frustrate their commercialization process.Herein,a hybrid SEI comprising abundant LiF,lithiophilic Li-Ge alloy,and Ge nanoparticles is constructed via a simple brush coating method.This fluorinated interface layer with embedded Ge-containing components isolates the Li anode from the corrosive electrolyte and facilitates homogenous Li nucleation as well as uniform growth.Consequently,the modified Li anode exhibits remarkable stability without notorious Li dendrites,delivering stable cycling lives of more than 1000 h for symmetric Li||Li cells and over 600 cycles for Li||Cu cells at 1 mA·cm^(−2).Moreover,the reinforced Li anodes endow multiple full-cell architectures with dramatically improved cyclability under different test conditions.This work provides rational guidance to design an artificial hybrid SEI layer and would stimulate more ideas to solve the dendrite issue and promote the further development of advanced LMBs.

Recent developments in three-dimensional Zn metal anodes for battery applications

Aqueous zinc(Zn)ion batteries(AZIBs)are regarded as one of the promising candidates for next-generation electrochemical energy storage systems due to their low cost,high safety,and environmental friendliness.However,the commercialization of AZIBs has been severely restricted by the growth of dendrite at the Zn metal anode.Tailoring the planar-structured Zn anodes into threedimensional(3D)structures has proven to be an effective way to modulate the plating/stripping behavior of Zn anodes,resulting in the suppression of dendrite formation.This review provides an up-to-date review of 3D structured Zn metal anodes,including working principles,design,current status,and future prospects.We aim to give the readers a comprehensive understanding of 3D-structured Zn anodes and their effective usage to enhance AZIB performance.

Flat Zn deposition at battery anode via an ultrathin robust interlayer

Rechargeable aqueous zinc(Zn)ion batteries(AZIBs)using low-cost and safe Zn metal anodes are considered promising candidates for future grid-scale energy storage systems,but the Zn dendrite problem severely hinders the further prospects of AZIBs.Regulating Zn depositing behaviors toward horizontal alignment is highly effective and thus has received huge attention.However,such a strategy is usually based on previous substrate engineering,which requires complex preparation or expensive equipment.Therefore,it is essential to develop a novel solution that can realize horizontally aligned Zn flake deposition via easy operation and low cost.Herein,we report an ultrathin and robust Kevlar membrane as the interlayer to mechanically suppress Zn dendrite growth.Compared to the randomly distributed flaky dendrites in the control group,the deposited Zn sheets would grow into parallel alignment with the existence of such interlayer.As the dendrites are effectively suppressed,Zn||Cu asymmetric,Zn||Zn symmetric,and Zn||MnO_(2)full batteries using Kevlar interlayer deliver significantly improved cycling stabilities.Furthermore,the Zn||MnO_(2)pouch cell using a Kevlar interlayer delivers stable cycling performance and shows stable operation during multi-angle folding.We believe this work provides a new possibility for regulating Zn deposition from a crystallographic perspective.

Water molecules regulation for reversible Zn anode in aqueous zinc ion battery:Mini-review

With the low cost,excellent safety and high theoretical specific capacity,aqueous zinc-ion batteries(AZ-IBs)are considered as a potential rival for lithium-ion batteries to promote the sustainable development of large-scale energy storage technologies.However,the notorious Zn dendrites and low Coulombic effi-ciency(CE)limit further development of AZIBs,due to the unstable electrochemical deposition/stripping behavior of Zn anode in aqueous zinc ion electrolytes.In this review,critical issues and advances are summarized in electrolyte engineering strategies.These strategies are focused on active water molecules during electrochemical process,including high-concentration electrolytes,ionic liquids,gel-polymer elec-trolytes and functional additives.With suppressed active water molecules,the solvation and de-solvation behavior of Zn^(2+)can be regulated,thereby modulating the electrochemical performance of Zn anode.Finally,the inherent problems of these strategies are discussed,and some promising directions are pro-vided on electrolytes engineering for high performance Zn anode in AZIBs.

Nitrogen and fluorine co-doped graphene for ultra-stable lithium metal anodes

The heteroatom doping strategies have been utilized to effectively improve the performance of the carbon-based hosts,such as graphene,for lithium(Li)metal in high energy density lithium metal batteries.However,solely doped graphene hosts often need the assistance of other materials with either better lithiophilicity or electronic conductance to achieve smooth and efficient deposition of Li,which adds extra weight or volume.Herein,graphene co-doped by nitrogen and fluorine(NFG)is employed as a stable host for Li,where the N-doping provides lithiophilicity and electronic conductivity lacked by F-doping and the F-doping facilitates fast formation of solid electrolyte interphase(SEI)retarded by N-doping.The well regulation of Li plating/stripping and SEI formation is verified by quickly stabilized and small-magnitude voltage hysteresis,which stands out in Li hosts based on doped graphene and leads to excellent long-term cycling performance of NFG based electrodes.A voltage hysteresis of 20 mV is observed for more than 850 h in the symmetrical cell.The remarkable efficiency of lithium usage is confirmed by the highcapacity retention of a full cell paired with LiFePO_(4)(LFP),which exceeds 70%after 500 cycles.This work presents an innovative perspective on the control of Li plating/stripping by simultaneously introducing two kinds of dopants into graphene and paving the way for exploring practical Li metal batteries.

Impact of lithium nitrate additives on the solid electrolyte interphase in lithium metal batteries

Lithium metal batteries(LMBs)represent a promising frontier in energy storage technology,offering high energy density but facing significant challenges.In this work,we address the critical challenge of lithium dendrite for-mation in LMBs,a key barrier to their efficiency and safety.Focusing on the potential of electrolyte additives,specifically lithium nitrate,to inhibit dendritic growth,we employ advanced multi-scale simulation techniques to explore the formation and properties of the solid electrolyte interphase(SEI)on the anode surface.Our study introduces a novel hybrid simulation methodology,HAIR(Hybrid ab initio and Reactive force field Molecular Dynamics),which combines ab initio molecular dynamics(AIMD)and reactive force field molecular dynamics(RMD).This approach allows for a more precise and reliable examination of the interaction mechanisms of nitrate additives within LMBs.Our findings demonstrate that lithium nitrate contributes to the formation of a stable and fast ionic conductor interface,effectively suppressing dendrite growth.These insights not only advance our un-derstanding of dendrite formation and mitigation strategies in lithium metal batteries,but also highlight the efficacy of HAIR as a pioneering tool for simulating complex chemical interactions in battery materials,offering significant implications for the broader field of energy storage technology.

Unlocking solid-state conversion batteries reinforced by hierarchical microsphere stacked polymer electrolyte

Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode-electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF_(3) conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This gC_(3)N_(4) stuffed polyethylene oxide(PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional(2 D)-nanosheet-built porous g-C_(3)N_(4) as three-dimensional(3 D) textured filler can strongly cross-link with PEO matrix and Li TFSI(TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity(2.5×10^(-4) S/cm at 60℃) and Li+transference number(0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO_(4) solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF_(3) cells show highly stabilized capacity as high as 300 m Ah/g even after 200 cycles and of 200 m Ah/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution(>55%) and diffusion coefficient(as high as10^(-12) cm^(2)/s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true "all-solid-state" due to the indispensable step of polysulfide solid-liquid conversion.

Double interface regulation: Toward highly stable lithium metal anode with high utilization

The undesirable Li dendrite growth and other knock-on issues have signifi-cantly plagued the application of Li metal anodes(LMAs).Herein,we report that the synergistic regulation of double interfaces adjacent to the metallic Li anode can effectively prevent the dendritic Li growth,significantly improving the cycling performance of LMAs under harsh conditions including high cur-rent density and high depth of discharge.Thorough comparison of electrolytes demonstrated that 1 M lithium bis(fluorosulfonyl)imide(LiFSI)in 1,2-dimethoxyethane(DME)can yield a robust and lithiophobic LiF-rich upper interface(solid electrolyte interphase).Besides,the Sb-based buffer layer forms a lithiophilic lower interface on current collector.The synergy of the upper and lower interfacial engineering plays an important role for outstanding cyclability of LMAs.Consequently,the plating/stripping of Li can be stably repeated for 835 and 329 cycles with an average Coulombic efficiency(CE)above 99%at 1 and 3 mA h cm?2,respectively.Surprisingly,the Li||Li symmetric cell can even withstand the baptism of current density up to 20 mA cm?2.The excellent performance validates that the facile synergistic regulating of interfaces adjacent to the metallic Li anode provides an effective pathway to stabilize LMAs.