Challenges in Li-ion battery high-voltage technology and recent advances in high-voltage electrolytes

The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capacity,energy density,service life,and rate discharge performance.By raising the voltage at the charge/discharge plateau,the energy density of the battery is increased.However,this causes transition metal dissolution,irreversible phase changes of the cathode active material,and parasitic electrolyte oxidation reactions.This article presents an overview of these concerns to provide a clear explanation of the issues involved in the development of electrolytes for high-voltage lithium-ion batteries.Additionally,solidstate electrolytes enable various applications and will likely have an impact on the development of batteries with high energy densities.It is necessary to improve the high-voltage performance of electrolytes by creating solvents with high thermal stabilities and high voltage resistance and additives with superior film forming performance,multifunctional capabilities,and stable lithium salts.To offer suggestions for the future development of high-energy lithium-ion batteries,we conclude by offering our own opinions and insights on the current development of lithium-ion batteries.

Design Strategies for Aqueous Zinc Metal Batteries with High Zinc Utilization: From Metal Anodes to Anode-Free Structures

Aqueous zinc metal batteries(AZMBs)are promising candidates for next-generation energy storage due to the excellent safety, environmental friendliness, natural abundance, high theoretical specific capacity, and low redox potential of zinc(Zn) metal. However,several issues such as dendrite formation, hydrogen evolution, corrosion, and passivation of Zn metal anodes cause irreversible loss of the active materials. To solve these issues, researchers often use large amounts of excess Zn to ensure a continuous supply of active materials for Zn anodes. This leads to the ultralow utilization of Zn anodes and squanders the high energy density of AZMBs. Herein, the design strategies for AZMBs with high Zn utilization are discussed in depth, from utilizing thinner Zn foils to constructing anode-free structures with theoretical Zn utilization of 100%, which provides comprehensive guidelines for further research. Representative methods for calculating the depth of discharge of Zn anodes with different structures are first summarized. The reasonable modification strategies of Zn foil anodes, current collectors with pre-deposited Zn, and anode-free aqueous Zn metal batteries(AF-AZMBs) to improve Zn utilization are then detailed. In particular, the working mechanism of AF-AZMBs is systematically introduced. Finally, the challenges and perspectives for constructing high-utilization Zn anodes are presented.

Novel high-voltage cathode for aqueous zinc ion batteries:Porous K_(0.5)VOPO_(4)·1.5H_(2)O with reversible solid-solution intercalation and conversion storage mechanism

Cathode materials that possess high output voltage,as well as those that can be mass-produced using facile techniques,are crucial for the advancement of aqueous zinc-ion battery(ZIBs)applications,Herein,we present for the first time a new porous K_(0.5)VOPO_(4)·1.5H_(2)O polyanionic cathode(P-KIVP)with high output voltage(above 1.2 V)that can be manufactured at room temperature using straightforward coprecipitation and etching techniques.The P-KVP cathode experiences anisotropic crystal plane expansion via a sequential solid-solution intercalation and phase co nversion pathway throughout the Zn^(2+)storage process,as confirmed by in-situ synchrotron X-ray diffraction and ex-situ X-ray photoelectron spectroscopy.Similar to other layered vanadium-based polyanionic materials,the P-KVP cathode experiences a progressive decline in voltage during the cycle,which is demonstrated to be caused by the irreversible conversion into amorphous VO_(x).By introducing a new electrolyte containing Zn(OTF)_(2) to a mixed triethyl phosphate and water solution,it is possible to impede this irreversible conversion and obtain a high output voltage and longer cycle life by forming a P-rich cathode electrolyte interface layer.As a proof-of-concept,the flexible fiber-shaped ZIBs based on modified electrolyte woven into a fabric watch band can power an electronic watch,highlighting the application potential of P-KVP cathode.

Multilevel carbon architecture of subnanoscopic silicon for fast‐charging high‐energy‐density lithium‐ion batteries

Silicon(Si)is widely used as a lithium‐ion‐battery anode owing to its high capacity and abundant crustal reserves.However,large volume change upon cycling and poor conductivity of Si cause rapid capacity decay and poor fast‐charging capability limiting its commercial applications.Here,we propose a multilevel carbon architecture with vertical graphene sheets(VGSs)grown on surfaces of subnanoscopically and homogeneously dispersed Si–C composite nanospheres,which are subsequently embedded into a carbon matrix(C/VGSs@Si–C).Subnanoscopic C in the Si–C nanospheres,VGSs,and carbon matrix form a three‐dimensional conductive and robust network,which significantly improves the conductivity and suppresses the volume expansion of Si,thereby boosting charge transport and improving electrode stability.The VGSs with vast exposed edges considerably increase the contact area with the carbon matrix and supply directional transport channels through the entire material,which boosts charge transport.The carbon matrix encapsulates VGSs@Si–C to decrease the specific surface area and increase tap density,thus yielding high first Coulombic efficiency and electrode compaction density.Consequently,C/VGSs@Si–C delivers excellent Li‐ion storage performances under industrial electrode conditions.In particular,the full cells show high energy densities of 603.5 Wh kg^(−1)and 1685.5 Wh L^(−1)at 0.1 C and maintain 80.7%of the energy density at 3 C.

Affinity-Engineered Flexible Scaffold toward Energy-Dense, Highly Reversible Na Metal Batteries

The practical deployment of metallic anodes in the energy-dense batteries is impeded by the thermodynamically unstable interphase in contact with the aprotic electrolyte,structural collapse of the substrates as well as their insufficient affinity toward the metallic deposits.Herein,the mechanical flexible,lightweight(1.2 mg cm^(−2))carbon nanofiber scaffold with the monodispersed,ultrafine Sn_(4)P_(3) nanoparticles encapsulation(Sn_(4)P_(3)NPs@CNF)is proposed as the deposition substrate toward the high-areal-capacity sodium loadings up to 4 mAh cm^(−2).First-principles calculations manifest that the alloy intermediates,namely the Na_(15)Sn_(4) and Na_(3)P matrix,exhibit the intimate Na affinity as the“sodiophilic”sites.Meanwhile,the porous CNF regulates the heterogeneous alloying process and confines the deposit propagation along the nanofiber orientation.With the precise control of pairing mode with the NaVPO4F cathode(8.7 mg cm^(−2)),the practical feasibility of the Sn_(4)P_(3) NPs@CNF anode(1^(*)Na excess)is demonstrated in 2 mAh single-layer pouch cell prototype,which achieves the 95.7%capacity retention for 150 cycles at various mechanical flexing states as well as balanced energy/power densities.

Functional additives for solid polymer electrolytes in flexible and high-energy-density solid-state lithium-ion batteries

Solid polymer electrolytes(SPEs)have become increasingly attractive in solid-state lithium-ion batteries(SSLIBs)in recent years because of their inherent properties of flexibility,processability,and interfacial compatibility.However,the commercialization of SPEs remains challenging for flexible and high-energy-density LIBs.The incorporation of functional additives into SPEs could significantly improve the electrochemical and mechanical properties of SPEs and has created some historical milestones in boosting the development of SPEs.In this study,we review the roles of additives in SPEs,highlighting the working mechanisms and functionalities of the additives.The additives could afford significant advantages in boosting ionic conductivity,increasing ion transference number,improving high-voltage stability,enhancing mechanical strength,inhibiting lithium dendrite,and reducing flammability.Moreover,the application of functional additives in high-voltage cathodes,lithium-sulfur batteries,and flexible lithiumion batteries is summarized.Finally,future research perspectives are proposed to overcome the unresolved technical hurdles and critical issues in additives of SPEs,such as facile fabrication process,interfacial compatibility,investigation of the working mechanism,and special functionalities.

Thick free-standing electrode based on carbon-carbon nitride microspheres with large mesopores for high-energy-density lithium-sulfur batteries

The development of sulfur cathodes with high areal capacity and high energy density is crucial for the practical application of lithium-sulfur batteries(LSBs).LSBs can be built by employing(ultra)high-loading sulfur cathodes,which have rarely been realized due to massive passivation and shuttling.Herein,microspheres of a carbon-carbon nitride composite(C@CN)with large mesopores are fabricated via molecular cooperative assembly.Using the C@CN-based electrodes,the effects of the large mesopores and N-functional groups on the electrochemical behavior of sulfur in LSB cells are thoroughly investigated under ultrahigh sulfur-loading conditions(>15 mgS cm^(-2)).Furthermore,for high-energy-density LSBs,the C@CN powders are pelletized into a thick free-standing electrode(thickness:500^m;diameter:11 mm)via a simple briquette process;here,the total amount of energy stored by the LSB cells is 39 mWh,corresponding to a volumetric energy density of 440 Wh L-1 with an areal capacity of 24.9 and 17.5 mAh cm^(-2) at 0.47 and 4.7 mA cm^(-2),respectively(at 24mgS cm^(-2)).These results have significantly surpassed most recent records due to the synergy among the large mesopores,(poly)sulfide-philic surfaces,and thick electrodes.The developed strategy with its potential for scale-up successfully fills the gap between laboratory-scale cells and practical cells without sacrificing the high areal capacity and high energy density,providing a solid foundation for the development of practical LSBs.

Superfast and solvent-free core-shell assembly of sulfur/carbon active particles by hail-inspired nanostorm technology for high-energy-density Li-S batteries

The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^(-2) delivers a stable area capacity of 6.6 mAh cm^(-2) over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^(-2) over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.

Toward high-sulfur-content,high-performance lithium-sulfur batteries:Review of materials and technologies

Lithium sulfur batteries(LSBs)are recognized as promising devices for developing next-generation energy storage systems.In addition,they are attractive rechargeable battery systems for replacing lithium-ion batteries(LIBs)for commercial use owing to their higher theoretical energy density and lower cost compared to those of LIBs.However,LSBs are still beset with some persistent issues that prevent them from being used industrially,such as the unavoidable dissolution of lithium polysulfide intermediates during electrochemical reactions and large volume expansion(up to 80%)upon the formation of Li_(2)S,resulting in serious battery life and safety limitations.In the process of solving these problems,it is necessary to maintain a high sulfur content in the cathode materials to ensure that the LSBs have high energy densities and excellent cycle performance.In this review,the novel preparation methods and cathode materials used for preparing LSBs in recent years are reviewed considering the sulfur content and cycle performance.In addition,the problems and difficulties in practically applying cathode materials are described,and the development trend is discussed.

Enhancing Hydrophilicity of Thick Electrodes for High Energy Density Aqueous Batteries

Thick electrodes can substantially enhance the overall energy density of batteries.However,insufficient wettability of aqueous electrolytes toward electrodes with conventional hydrophobic binders severely limits utilization of active materials with increasing the thickness of electrodes for aqueous batteries,resulting in battery performance deterioration with a reduced capacity.Here,we demonstrate that controlling the hydrophilicity of the thicker electrodes is critical to enhancing the overall energy density of batteries.Hydrophilic binders are synthesized via a simple sulfonation process of conventional polyvinylidene fluoride binders,considering physicochemical properties such as mechanical properties and adhesion.The introduction of abundant sulfonate groups of binders(i)allows fast and sufficient electrolyte wetting,and(ii)improves ionic conduction in thick electrodes,enabling a significant increase in reversible capacities under various current densities.Further,the sulfonated binder effectively inhibits the dissolution of cathode materials in reactive aqueous electrolytes.Overall,our findings significantly enhance the energy density and contribute to the development of practical zinc-ion batteries.

Polymer dispersed ionic liquid electrolytes with high ionic conductivity for ultrastable solid-state lithium batteries

Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for building solid-state lithium batteries due to their excellent flexibility,scalability,and interfacial compatibility with electrodes.However,the low ionic conductivity and poor cyclic stability of SPEs do not meet the requirements for practical applications of lithium batteries.Here,a novel polymer dispersed ionic liquid-based solid polymer electrolyte(PDIL-SPE)is fabricated using the in situ polymerization-induced phase separation(PIPS)method.The as-prepared PDIL-SPE possesses both outstanding ionic conductivity(0.74 mS cm^(-1) at 25℃)and a wide electrochemical window(up to 4.86 V),and the formed unique three-dimensional(3D)co-continuous structure of polymer matrix and ionic liquid in PDIL-SPE can promote the transport of lithium ions.Also,the 3D co-continuous structure of PDIL-SPE effectively accommodates the severe volume expansion for prolonged lithium plating and stripping processes over 1000 h at 0.5 mA cm^(-2) under 25℃.Moreover,the LiFePO_(4)//Li coin cell can work stably over 150 cycles at a 1 C rate under room temperature with a capacity retention of 90.6%from 111.1 to 100.7 mAh g^(-1).The PDIL-SPE composite is a promising material system for enabling the ultrastable operation of solid-state lithium-metal batteries.

Long-lasting,reinforced electrical networking in a high-loading Li_(2)S cathode for high-performance lithium–sulfur batteries

Realizing a lithium sulfide(Li_(2)S)cathode with both high energy density and a long lifespan requires an innovative cathode design that maximizes electrochemical performance and resists electrode deterioration.Herein,a high-loading Li_(2)S-based cathode with micrometric Li_(2)S particles composed of two-dimensional graphene(Gr)and one-dimensional carbon nanotubes(CNTs)in a compact geometry is developed,and the role of CNTs in stable cycling of high-capacity Li–S batteries is emphasized.In a dimensionally combined carbon matrix,CNTs embedded within the Gr sheets create robust and sustainable electron diffusion pathways while suppressing the passivation of the active carbon surface.As a unique point,during the first charging process,the proposed cathode is fully activated through the direct conversion of Li_(2)S into S_(8) without inducing lithium polysulfide formation.The direct conversion of Li_(2)S into S_(8) in the composite cathode is ubiquitously investigated using the combined study of in situ Raman spectroscopy,in situ optical microscopy,and cryogenic transmission electron microscopy.The composite cathode demonstrates unprecedented electrochemical properties even with a high Li_(2)S loading of 10 mg cm^(–2);in particular,the practical and safe Li–S full cell coupled with a graphite anode shows ultra-long-term cycling stability over 800 cycles.

A Tip-Inhibitor Interphase Embedded with Soluble Polysulfides for High-Voltage Li Metal Batteries

The high-voltage battery has now become a goal in order to meet the demands for high energy density.However,the severe side reactions between Li metal and carbonate-based electrolytes in this system result in unstable interphase,leading to non-uniform Li-ion flux and thus aggravating the dendrite growth of Li.The protect interphase,traditional solid electrolyte interface(SEI),is a loose solid layer consisted of many components,which generally does not possess the function of preventing the lithium budding.Herein,based on polysulfide solubility in ester,we proposed a strategy to eliminate the dendrite by constructing a unique SEI in which the dynamic polysulfides were in situ formed and encapsuled.For this purpose,a 2-fluorophenylsulfur pentafluoride(2-FSPF)was employed as an additive in carbonate-based electrolyte that can be decomposed electrochemically during battery operation to form such a polysulfide-rich interphase.These polysulfides with certain fluidity can adhere to dynamically the budding tip of Li metal,as a so-called tip-inhibitor,when the local current density of the tip rising,thus to hinder Li^(+)diffusion toward the tip,resulting in inhibiting the further growth of Li dendrites and leveling the Li deposition.At the current density of 1 mA cm^(-2),the average Coulombic efficiency of Li//Cu cells is as high as 98.39%during 600 cycles,and the stable cycling of Li//Li symmetric cell reaches 3500 h.Furthermore,due to the high anodic stability,the Li//high-voltage LiCoO_(2)(LCO)full cells and Li–O_(2)battery achieve excellent cycle performance with lean electrolyte.

High-Voltage Aqueous Zinc Batteries Achieved by Tri-functional Metallic Bipolar Electrodes

Aqueous rechargeable zinc batteries are very attractive for energy storage applications due to their low cost and high safety.However,low operating voltages limit their further development.For the first time,this work proposes a unique approach to increase the voltages of aqueous zinc batteries by using tri-functional metallic bipolar electrode with good electrochemical activity and ultrahigh electronic conductivity,which not only participates in redox reactions,but also functions as an electrical highway for charge transport.Furthermore,bipolar electrode can replace expensive ion selective membrane to separate electrolytes with different pH;thus,redox couples with higher potential in acid condition and Zn=Zn(OH)^(2-)_(4) couple with lower potential in alkaline condition can be employed together,leading to high voltages of aqueous zinc batteries.Herein,two types of metallic bipolar electrodes of Cu and Ag are utilized based on three kinds of aqueous zinc batteries:Zn–MnO_(2),Zn–I_(2),and Zn–Br_(2).The voltage of aqueous Zn–MnO_(2) battery is raised to 1.84 V by employing one Cu bipolar electrode,which shows no capacity attenuation after 3500 cycles.Moreover,the other Ag bipolar electrode can be adopted to successfully construct Zn–I_(2) and Zn–Br_(2) batteries exhibiting much higher voltages of 2.44 and 2.67 V,which also show no obvious capacity degradation for 1000 and 800 cycles,representing decent cycle stability.Since bipolar electrode can be applied in a large family of aqueous batteries,this work offers an elaborate high-voltage concept based on tri-functional metallic bipolar electrode as a model system to open a door to explore high-voltage aqueous batteries.

Construction of strong built-in electric field in binary metal sulfide heterojunction to propel high-loading lithium-sulfur batteries

The practical application of lithium-sulfur(Li-S)batteries is greatly hindered by soluble polysulfides shuttling and sluggish sulfur redox kinetics.Rational design of multifunctional hybrid materials with superior electronic conductivity and high electrocatalytic activity,e.g.,heterostructures,is a promising strategy to solve the above obstacles.Herein,a binary metal sulfide MnS-MoS_(2) heterojunction electrocatalyst is first designed for the construction of high-sulfur-loaded and durable Li-S batteries.The MnS-MoS_(2) p-n heterojunction shows a unique structure of MoS_(2) nanosheets decorated with ample MnS nanodots,which contributes to the formation of a strong built-in electric field at the two-phase interface.The MnS-MoS_(2) hybrid host shows strong soluble polysulfide affinity,enhanced electronic conductivity,and exceptional catalytic effect on sulfur reduction.Benefiting from the synergistic effect,the as-derived S/MnS-MoS_(2) cathode delivers a superb rate capability(643 m A h g^(-1)at 6 C)and a durable cyclability(0.048%decay per cycle over 1000 cycles).More impressively,an areal capacity of 9.9 m A h cm^(-2)can be achieved even under an extremely high sulfur loading of 14.7 mg cm^(-2)and a low electrolyte to sulfur ratio of 2.9μL mg^(-1).This work provides an in-depth understanding of the interfacial catalytic effect of binary metal compound heterojunctions on sulfur reaction kinetics.

Fluorinated soft carbon as an ultra-high energy density potassium-ion battery cathode enabled by a ternary phase K_(x)FC

Fluorinated carbons(CFx)have been widely applied as lithium primary batteries due to their ultra-high energy density.It will be a great promise if CFx can be rechargeable.In this study,we rationally tune the C-F bond strength for the alkaline intercalated CFx via importing an electronegative weaker element K instead of Li.It forms a ternary phase K_(x)FC instead of two phases(LiF+C)in lithium-ion batteries.Meanwhile,we choose a large layer distance and more defects CFx,namely fluorinated soft carbon,to accommodate K.Thus,we enable CFx rechargeable as a potassium-ion battery cathode.In detail fluorinated soft carbon CF_(1.01) presents a reversible specific capacity of 339 mA h g^(-1)(797 Wh kg^(-1))in the 2nd cycle and maintains 330 mA h g^(-1)(726 Wh kg^(-1))in the 15th cycle.This study reveals the importance of tuning chemical bond stability using different alkaline ions to endow batteries with rechargeability.This work provides good references for focusing on developing reversible electrode materials from popular primary cell configurations.

A surfactant-modified composite separator for high safe lithium ion battery

Separators have been gaining increasing attention to improve the performance of lithium ion batteries(LIBs),especially for high safe and long cycle life.However,commercial polyolefin separators still face the problems of rapid capacity decay and safety issues due to the poor wettability with electrolytes and low thermal stability.Herein,a novel composite separator is proposed by introducing a surfactant of sodium dodecyl thiosulfate(SDS)into the polytetrafluoroethylene(PTFE)substrate with the binder of polyacrylic acid(PAA)through the suction filtration method.The introduction of PAA/SDS enhances the adsorption energy between PTFE substrate and electrolyte through density functional theory calculations,which improves wettability and electrolyte uptake of the separator significantly.The asachieved composite separator enables the LIBs to own high Li^(+)conductivity(0.64×10^(-3)S cm^(-1))and Li^(+)transference number(0.63),further leading to a high capacity retention of 93.50%after 500 cycles at 1 C.In addition,the uniform and smooth surface morphology of Li metal employed the composite separator after cycling indicates that the lithium dendrites can be successfully inhibited.This work indicates a promising route for the preparation of a novel composite separator for high safe LIBs.

Concentrated ternary ether electrolyte allows for stable cycling of a lithium metal battery with commercial mass loading high-nickel NMC and thin anodes

A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.

Enlarging Zn deposition space via regulating Sn-induced effective interface for high areal capacity zinc-based flow battery

Zinc-based flow batteries(ZFBs)have aroused great favor in large-scale energy storage due to the high security and low cost.However,the low areal capacity arising from the limited space for Zn plating hinders the further development.Herein,a novel carbon felt-Sn-carbon felt sandwich host(CSCH)is designed and constructed.Benefiting from the strong chemical absorption and the dehydration effect on Zn(H_(2)O)_(6)^(2+),the Sn activation layer in the CSCH demonstrates the lowest comprehensive resistance for Zn deposition.Thus,Zn is induced to nucleate preferentially on the Sn activation layer,and grows towards the membrane,regulating the spatial distribution of Zn electrochemical deposits,which remarkably improves the areal capacity and cyclic stability of Zn anode.Consequently,the zinc-bromine flow batteries equipped with CSCH electrodes can achieve the ultra-high areal capacity of 120 mA h cm^(-2)at 80 mA cm^(-2),and run stably for 140 h with average energy efficiency of 80.3%in the extreme condition(80 mA cm^(-2),80 mA h cm^(-2)).This innovative work will inspire future advanced designs for high areal capacity electrodes in ZFBs.

Manipulating Zn^(2+)solvation environment in poly(propylene glycol)-based aqueous Li^(+)/Zn^(2+)electrolytes for high-voltage hybrid ion batteries

Compared with aqueous single-ion batteries,rechargeable aqueous hybrid ion batteries,especially Li^(+)/Zn^(2+)hybrid ion batteries,are receiving extensive interest owing to their low cost,high operating voltage,and energy density.However,their working voltage and lifespan are limited by the decomposition of water and the growth of Zn dendrites.Herein,detrimental side reactions induced by the water reduction and the Zn dendrite growth are successfully suppressed by a poly(propylene glycol)(PPG)-based hybrid ion electrolyte[(1 m Zn(TFSI)2+10 m LiTFSI)in PPG/H2O].The addition of PPG in the electrolyte can not only enhance the bonding strength of hydrogen-bond in water but also tailor the solvation sheath of Zn2+as revealed by synchrotron X-rays.The participated solvation of PPG with Zn^(2+)can weaken Zn-H_(2)O interactions and redistribute Zn^(2+)flux on the surface of the Zn anode,thus inducing favorably even deposition of Zn.In addition,the decomposition of TFSI-contributes a ZnF_(2)-enriched solid electrolyte interface at the Zn anode to further prevent water decomposition and restrain Zn dendrites.The PPG-based electrolyte enables 2.1 V LiMnO_(2)//Zn batteries to deliver high specific capacities(121.7 mAh g^(-1)for a coin cell and 90 mAh g^(-1)for a pouch cell),and maintain 80%of the capacity over 700 cycles at 0.5 C,suggesting a promising pathway for highly reversible aqueous hybrid ion batteries.