Thioacetamide Additive Homogenizing Zn Deposition Revealed by In Situ Digital Holography for Advanced Zn Ion Batteries

Zinc ion batteries are considered as potential energy storage devices due to their advantages of low-cost,high-safety,and high theoretical capacity.However,dendrite growth and chemical corrosion occurring on Zn anode limit their commercialization.These problems can be tackled through the optimization of the electrolyte.However,the screening of electrolyte additives using normal electrochemical methods is time-consuming and labor-intensive.Herein,a fast and simple method based on the digital holography is developed.It can realize the in situ monitoring of electrode/electrolyte interface and provide direct information concerning ion concentration evolution of the diffusion layer.It is effective and time-saving in estimating the homogeneity of the deposition layer and predicting the tendency of dendrite growth,thus able to value the applicability of electrolyte additives.The feasibility of this method is further validated by the forecast and evaluation of thioacetamide additive.Based on systematic characterization,it is proved that the introduction of thioacetamide can not only regulate the interficial ion flux to induce dendrite-free Zn deposition,but also construct adsorption molecule layers to inhibit side reactions of Zn anode.Being easy to operate,capable of in situ observation,and able to endure harsh conditions,digital holography method will be a promising approach for the interfacial investigation of other battery systems.

Bilayer separator enabling dendrite-free zinc anode with ultralong lifespan >5000 h

Aqueous zinc(Zn)batteries with Zn metal anodes are promising clean energy storage devices with intrinsic safety and low cost.However,Zn dendrite growth severely restricts the use of Zn anodes.To effectively suppress Zn dendrite growth,we propose a bilayer separator consisting of commercial butter paper and glassfiber membrane.The dense cellulose-based butter paper(BP)with low zincophilicity and high mechanical properties prevents the pore-filling behavior of deposited Zn and related separator piercing,effectively suppressing the Zn dendrite growth.As a result,the bilayer separators endow the ZnjjZn symmetrical batteries with a superlong cycling life of Zn anodes(over 5000 h)at 0.5 mA cm^(-2) and the full batteries enhanced capacity retention,demonstrating the advancement of the bilayer separator to afford excellent cyclability of aqueous metal batteries.

Multifunctional Sodium Gluconate Electrolyte Additive Enabling Highly Reversible Zn Anodes

Sodium gluconate(SG)is reported as an electrolyte additive for rechargeable aqueous zinc batteries.The SG addition is proposed to modulate the nucleation overpotential and plating behaviors of Zn by forming a shielding buffer layer because of the adsorption priority and large steric hindrance effect,which contributes to limited rampant Zn^(2+)diffusion and mitigated hydrogen evolution and corrosion.With the introduction of 30 mmol/L SG in 2 mol/L ZnSO_(4)electrolyte,the Zn anode harvests a reversible cycling of 1200 h at 5 mA/cm^(2)and a high average Coulombic efficiency of Zn plating/stripping(99.6%).Full cells coupling Zn anode with V_(2)O_(5)·1.6H_(2)O or polyaniline cathode far surpass the SG additivefree batteries in terms of cycle stability and rate capability.This work provides an inspiration for design of a high-effective and low-cost electrolyte additive towards Zn-based energy storage devices.

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.

Issues and solutions toward zinc anode in aqueous zinc-ion batteries: A mini review

Aqueous zinc-ion batteries(ZIBs)have been intensively investigated as potential energy storage devices on account of their low cost,environmental benignity,and intrinsically safe merits.With the exploitation of highperformance cathode materials,electrolyte systems,and in-depth mechanism investigation,the electrochemical performances of ZIBs have been greatly enhanced.However,there are still some challenges that need to be overcome before its commercialization.Among them,the obstinate dendrites,corrosion,and hydrogen evolution reaction(HER)on Zn anodes are critical issues that severely limit the practical applications of ZIBs.To address these issues,various strategies have been proposed,and tremendous progress has been achieved in the past few years.In this article,we analyze the origins and effects of the dendrites,corrosion,and HER on Zn anodes in neutral and mildly acid aqueous solutions at first.And then,a scientific understanding of the fundamental design principles and strategies to suppress these problems are emphasized.Apart from these,this article also puts forward some requirements for the practical applications of Zn anodes as well as several cost-effectivemodifying strategies.Finally,perspectives on the future development of Zn anodes in aqueous solutions are also briefly anticipated.This article provides pertinent insights into the challenges on anodes for the development of highperformance ZIBs,which will greatly contribute to their practical applications.

Flexible PEDOT:PSS nanopapers as“anion-cation regulation”synergistic interlayers enabling ultra-stable aqueous zinc-iodine batteries

Aqueous zinc-iodine(Zn-I_(2))batteries are promising candidates for low-cost grid-scale energy storage systems.However,the long-term stability and energy density of the Zn-I_(2)batteries are largely hindered by the lack of feasible and scalable methods that coherently suppress polyiodide shuttling and Zn dendrites growth,especially at high current densities.Herein,a flexible,thin and lightweight poly(3,4-ethy lenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)nanopaper is designed as an“anion-cation regulation”synergistic interlayer to tackle the above issues.The PEDOT:PSS interlayer exhibits a 3D nanofibrous network with uniformly distributed mesopores,abundant polar groups and intrinsic conductivity,which renders an even Zn^(2+)flux at Zn anode and facilitates homogeneous current distributions at I_(2)cathode.Meanwhile,such interlayer can act as physiochemical shield to enhance the utilization of I_(2)cathode via the coulombic repulsion and chemical adsorption effect against polyiodide shuttling.Thus,long-term dendrite-free Zn plating/stripping is achieved at simultaneous high current density and high areal capacity(550 h at 10 m A cm^(-2)/5 m Ah cm^(-2)).Zn-I_(2)batteries harvest a high capacity(230 m Ah g^(-1)at 0.1 A g^(-1))and an ultralong lifespan(>20000 cycles)even at 10 A g^(-1).This work demonstrates the potential use of the multifunctional interlayers for Zn-I_(2)battery configuration innovation by synergistic regulation of cations and anions at the electrodes/electrolyte interface.

Cyclohexanedodecol-Assisted Interfacial Engineering for Robust and High-Performance Zinc Metal Anode

Aqueous zinc-ion batteries(AZIBs)can be one of the most promising electrochemical energy storage devices for being non-flammable,low-cost,and sustainable.However,the challenges of AZIBs,including dendrite growth,hydrogen evolution,corrosion,and passivation of zinc anode during charging and discharging processes,must be overcome to achieve high cycling performance and stability in practical applications.In this work,we utilize a dual-func-tional organic additive cyclohexanedodecol(CHD)to firstly establish[Zn(H2O)5(CHD)]2+complex ion in an aqueous Zn electrolyte and secondly build a robust protection layer on the Zn surface to overcome these dilemmas.Systematic experiments and theoretical calculations are carried out to interpret the working mechanism of CHD.At a very low concentration of 0.1 mg mL^(−1) CHD,long-term reversible Zn plating/stripping could be achieved up to 2200 h at 2 mA cm^(−2),1000 h at 5 mA cm^(−2),and 650 h at 10 mA cm^(−2) at the fixed capacity of 1 mAh cm^(−2).When matched with V_(2)O_(5) cathode,the resultant AZIBs full cell with the CHD-modified electrolyte presents a high capacity of 175 mAh g^(−1) with the capacity retention of 92%after 2000 cycles under 2 A g^(−1).Such a performance could enable the commercialization of AZIBs for applications in grid energy storage and industrial energy storage.

Interface engineering of Zn meal anodes using electrochemically inert Al_(2)O_(3)protective nanocoatings

Aqueous rechargeable Zn-ion batteries are regarded as a promising alternative to lithium-ion batteries owing to their high energy density,low cost,and high safety.However,their commercialization is severely restricted by the Zn dendrite formation and side reactions.Herein,we propose that these issues can be minimized by modifying the interfacial properties through introducing electrochemically inert Al_(2)O_(3)nanocoatings on Zn meal anodes(Al_(2)O_(3)@Zn).The Al_(2)O_(3)nanocoatings can effectively suppress both the dendrite growth and side reactions.As a result,the Al_(2)O_(3)@Zn symmetric cells show excellent electrochemical performance with a long lifespan of more than 4,000 h at 1 mA·cm^(−2)and 1 mAh·cm^(−2).Meanwhile,the assembled Al_(2)O_(3)@Zn//V_(2)O_(5)full cells can deliver a high capacity(236.2 mAh·g^(−1))and long lifespan with a capacity retention of 76.11%after 1,000 cycles at 4 A·g^(−1).

Recent progress,mechanisms,and perspectives for crystal and interface chemistry applying to the Zn metal anodes in aqueous zinc-ion batteries

The need for large-scale electrochemical energy storage devices in the future has spawned several new breeds of batteries in which aqueous zinc ion batteries(AZIBs)have attracted great attention due to their high safety,low cost,and excellent electrochemical performance.In the current research,the dendrite and corrosion caused by aqueous electrolytes are the main problems being studied.However,the research on the zinc metal anode is still in its infancy.We think it really needs to provide clear guidelines about how to reasonably configure the system of AZIBs to realize high-energy density and long cycle life.Therefore,it is worth analyzing the works on the zinc anode,and several strategies are proposed to improve the stability and cycle life of the battery in recent years.Based on the crystal chemistry and interface chemistry,this review reveals the key factors and essential causes that inhibit dendrite growth and side reactions and puts forward the potential prospects for future work in this direction.It is foreseeable that guiding the construction of AZIBs with high-energy density and long cycle life in various systems would be quite possible by following this overview as a roadmap.

锌离子传导聚合物缓冲层:抑制锌离子水电池锌负极寄生反应

由于锌金属在电解液中热力学不稳定而自发地发生寄生反应(析氢、枝晶生长等),水系锌离子电池的商业化应用受到了阻碍.因此,我们构建了一种高粘附性的锌离子传导聚合物聚乙烯醇缩甲醛(PVF)缓冲层,来抑制这些寄生反应的发生,从而提高锌沉积的可逆性.这种致密的人工缓冲层不仅能有效隔绝电解质与锌负极之间的直接接触,还能适应锌沉积/剥离过程中的体积膨胀,并引导锌成核过程.具体来说,PVF层可提高成核过电位,并促进Zn2+的三维扩散过程,使PVF层下的Zn2+沉积通量均匀化.我们设计的PVF@Zn具有高循环稳定性和不易生成枝晶的特点,基于该电极的对称电池的长循环寿命超过5200 h,比Zn负极电池提高了近35倍,甚至可以在40.0 mA cm^(−2)的超高电流密度下稳定运行.此外,PVF@Zn||NVO全电池在1.0 A g^(−1)的条件下进行2400个循环后,仍能保持172.4 mA h g^(−1)的比容量.这种通过消除自发寄生反应并调节锌均匀沉积及成核的策略,为设计实用化高性能锌负极提供了重要借鉴.

A diluent protective organic additive electrolyte of hydrophilic hyperbranched polyester for long-life reversible aqueous zinc manganese oxide batteries

hydrophilic hyperbranched polyester(poly(tetramethylol acetylenediurea(TA)-CO-succinyl chloride)(PTS))was proposed to be used as an organic additive in aqueous ZnSO_(4)electrolyte to achieve a highly reversible zinc/manganese oxide battery.It is found that the zinc symmetric battery based on the 2.0 wt.%PTS/ZnSO_(4)electrolyte showed a long cycle stability of more than 2400 h at 1.0 mA·cm^(-2),which is much longer than that including the blank ZnSO_(4)electrolyte(140 h).Furthermore,the capacity retention of the Zn||MnO_(2)full cells employing the 2.0 wt.%PTS/ZnSO_(4)electrolyte remained 85%after 100 cycles at 0.2 A·g^(1),which is much higher than 20%capacity retention of the cell containing the blank ZnSO_(4)electrolyte,and also greater than 59.6%capacity retention of the cell including the 10.0 wt.%TA/ZnSO_(4)electrolyte.By using 2.0 wt.%PTS/ZnSO_(4)electrolytes,the capacity retention of the Zn||MnO_(2)full cells even reached 65%after 2000 cycles at a higher current density of 1.0 A·g^(1).It is further demonstrated that the PTS was firmly adsorbed on the zinc anode surface to form a protective layer.

Comprehensive review on zinc-ion battery anode: Challenges and strategies

Zinc-ion batteries(ZIBs)have been extensively investigated and discussed as promising energy storage devices in recent years owing to their low cost,high energy density,inherent safety,and low environmental impact.Nevertheless,several challenges remain that need to be prioritized before realizing the wide-spread application of ZIBs.In particular,the development of zinc anodes has been hindered by many challenges,such as inevitable zinc dendrites,corrosion passivation,and the hydrogen evolution reaction(HER),which have severely limited the practical application of high-performance ZIBs.This review starts with a systematic discussion of the origins of zinc dendrites,corrosion passiv-ation,and the HER,as well as their effects on battery performance.Subse-quently,we discuss solutions to the above problems to protect the zinc anode,including the improvement of zinc anode materials,modification of the anode–electrolyte interface,and optimization of the electrolyte.In particular,this review emphasizes design strategies to protect zinc anodes from an inte-grated perspective with broad interest rather than a view with limited focus.In the final section,comments and perspectives are provided for the future design of high-performance zinc anodes.

Effects of Sb Content on Solidification Pathways and Grain Size of AZ91 Magnesium Alloy

The phase constitution and solidification pathways of AZ91＋xSb（x = 0, 0.1, 0.5, 1, in wt%） alloys were investigated through ways of microstructure observation, thermal analysis technique, and thermodynamic calculation. It was found that the non-equilibrium solidification microstructure of AZ91＋xSb（x = 0.1, 0.5, 1） is composed of a-Mg matrix, b-Mg17Al12 phase, and intermetallic compound Mg3Sb2. The grain size of the alloys with different Sb contents was quantitatively determined by electron backscattered diffraction technique which shows no grain refinement in Sb-containing AZ91 alloy. Thermodynamic calculations are in reasonable agreement with thermal analysis results, showing that the Mg3Sb2 phase forms after a-Mg nucleation, thus impossible acts as heterogeneous nucleus for a-Mg dendrite. Besides,the solid fraction at dendrite coherency point（fDCPs） determined from thermal analysis decreases slightly with increasing Sb content, which is consistent with the fact that Sb does not refine the grain size of AZ91 alloy.