Trace Amounts of Triple-Functional Additives Enable Reversible Aqueous Zinc-Ion Batteries from a Comprehensive Perspective

Although their cost-effectiveness and intrinsic safety,aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction,Zn corrosion and passivation,and Zn dendrite formation on the anode.Despite numerous strategies to alleviate these side reactions have been demonstrated,they can only provide limited performance improvement from a single aspect.Herein,a triple-functional additive with trace amounts,ammonium hydroxide,was demonstrated to comprehensively protect zinc anodes.The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes.Moreover,cationic NH^(4+)can preferentially adsorb on the Zn anode surface to shield the“tip effect”and homogenize the electric field.Benefitting from this comprehensive protection,dendrite-free Zn deposition and highly reversible Zn plating/stripping behaviors were realized.Besides,improved electrochemical performances can also be achieved in Zn//MnO_(2)full cells by taking the advantages of this triple-functional additive.This work provides a new strategy for stabilizing Zn anodes from a comprehensive perspective.

Strategic comparison of membrane-assisted and membrane-less water electrolyzers and their potential application in direct seawater splitting(DSS)

Electrocatalytic splitting of water by means of renewable energy as the electricity supply is one of the most promising methods for storing green renewable energy as hydrogen. Although two-thirds of the earth’s surface is covered with water, there is inadequacy of freshwater in most parts of the world. Hence, splitting seawater instead of freshwater could be a truly sustainable alternative. However, direct seawater splitting faces challenges because of the complex composition of seawater. The composition, and hence, the local chemistry of seawater may vary depending on its origin, and in most cases, tracking of the side reactions and standardizing and customizing the catalytic process will be an extra challenge. The corrosion of catalysts and competitive side reactions due to the presence of various inorganic and organic pollutants create challenges for developing stable electro-catalysts. Hence, seawater splitting generally involves a two-step process, i.e., purification of seawater using reverse osmosis and then subsequent fresh water splitting. However, this demands two separate chambers and larger space, and increases complexity of the reactor design. Recently, there have been efforts to directly split seawater without the reverse osmosis step. Herein, we represent the most recent innovative approaches to avoid the two-step process, and compare the potential application of membrane-assisted and membrane-less electrolyzers in direct seawater splitting(DSS). We particularly discuss the device engineering, and propose a novel electrolyzer design strategies for concentration gradient based membrane-less microfluidic electrolyzer.

Controllable Hydrothermal Synthesis of Cd₂Ge₂O₆Nanostructures

Various Cd2Ge2O6 nanostructures, including nanorods, nanoparticles, nanowires and erythrocyte/ flower/disc-like superstructures have been successfully prepared by hydrothermal methods, which are simply tuned by changing the reaction temperature, surfactants, and the molar ratio of Cd and Ge precursors in aqueous solution. These morphologies can be simply controlled by only selecting the reactants and controlling experimental conditions with excellent reproducibility. These studies about the Cd2Ge2O6 nanostructures reveal that temperature is a crucial parameter to tune the morphologies from nanoparticles to nanorods. By adding various surfactants, different nanostructures such as flower/disc-like nanosticks could be obtained. Replacing Cd(CH3COO)22H2O with CdO as the precusor results in the formation of ultralong nanowires with CTAB as surfactant. Molar ratio of GeO2 to CdO was demonstrated as an important factor to influence the surface smoothness of nanowires. It is believed that the simple hydrothermal route may be the useful route to synthesize variable germanate nanostructures for various applications.

Bi nanoparticles encapsulated in nitrogen-doped carbon as a long-life anode material for magnesium batteries

Bismuth has garnered significant interest as an anode material for magnesium batteries(MBs) because of its high volumetric specific capacity and low working potential. Nonetheless, the limited cycling performance(≤100 cycles) limits the practical application of Bi as anode for MBs. Therefore, the improvement of Bi cycling performance is of great significance to the development of MBs and is also full of challenges. Here, Bi nanoparticles encapsulated in nitrogen-doped carbon with single-atom Bi embedded(Bi@NC) are prepared and reported as an anode material for MBs. Bi@NC demonstrates impressive performance, with a high discharge capacity of 347.5 mAh g^(-1) and good rate capability(206.4 mAh g^(-1)@500 mA g^(-1)) in a fluoride alkyl magnesium salt electrolyte. In addition, Bi@NC exhibits exceptional long-term stability, enduring 400 cycles at 500 mA g^(-1). To the best of our knowledge, among reported Bi and Bi-based compounds for MBs, Bi@NC exhibits the longest cycle life in this work. The magnesium storage mechanism of Bi@NC is deeply studied through X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. This work provides some guidance for further improving the cycling performance of other alloy anodes in MBs.

Mo/Fe bimetallic pyrophosphates derived from Prussian blue analogues for rapid electrocatalytic oxygen evolution

Efficient and stable oxygen evolution electrocatalysts are indispensable for industrial applications of water splitting and hydrogen production.Herein,a simple and practical method was applied to fabricate(Mo,Fe)P2O7@NF electrocatalyst by directly growing Mo/Fe bimetallic pyrophosphate derived from Prussian blue analogues on three-dimensional porous current collector.In alkaline media,the developed material possesses good hydrophilic features and exhibits best-in-class oxygen evolution reaction(OER)performances.Surprisingly,the(Mo,Fe)P_(2)O_(7)@NF only requires overpotentials of 250 and 290 mV to deliver 100 and 600 mA cm^(-2)in 1 mol L^(-1)KOH,respectively.Furthermore,the(Mo,Fe)P_(2)O_(7)@NF shows outstanding performances in alkaline salty water and 1 mol L^(-1)high purity KOH.A worthwhile pathway is provided to combine bimetallic pyrophosphate with commercial Ni foam to form robust electrocatalysts for stable electrocatalytic OER,which has a positive impact on both hydrogen energy application and environmental restoration.

Structural engineering of cathodes for improved Zn-ion batteries

Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stable and high capacity cathode materials due to their complicated reaction mechanism and slow Zn-ion transport kinetics.This study reports a unique 3 D ’flower-like’ zinc cobaltite(ZnCo_(2)O_(4-x)) with enriched oxygen vacancies as a new cathode material for aqueous ZIBs.Computational calculations reveal that the presence of oxygen vacancies significantly enhances the electronic conductivity and accelerates Zn^(2+) diffusion by providing enlarged channels.The as-fabricated batteries present an impressive specific capacity of 148.3 mAh g^(-1) at the current density of 0.05 A g^(-1),high energy(2.8 Wh kg^(-1)) and power densities(27.2 W kg^(-1)) based on the whole device,which outperform most of the reported aqueous ZIBs.Moreover,a flexible solid-state pouch cell was demonstrated,which delivers an extremely stable capacity under bending states.This work demonstrates that the performance of Zn-ion storage can be effectively enhanced by tailoring the atomic structure of cathode materials,guiding the development of low-cost and eco-friendly energy storage materials.

Realizing optimal hydrogen evolution reaction properties via tuning phosphorous and transition metal interactions

Hydrogen is one of the most attractive renewables for future energy application,therefore it is vital to develop cost-effective and highlyefficient electrocatalysts for the hydrogen evolution reaction(HER)to promote the generation of hydrogen from mild methods.In this work,Co–Mo phosphide nanosheets with the adjustable ratio of Co and Mo were fabricated on carbon cloth by a facile hydrothermal-annealing method.Owing to the unique nanostructures,abundant active surfaces and small resistance were achieved.Excellent electrocatalytic performances are obtained,such as the small overpotential of^67.3 mV to realize a current density of 10 mA cm^(-2) and a Tafel slope of 69.9 mV dec^(-1).Rapid recovery of the current response under multistep chronoamperometry is realized and excellent stability retained after the CV test for 2000 cycles.The change of electronic states of different elements was carefully studied which suggested the optimal electrochemical performance can be realized by tuning phosphorous and metal interactions.

Lithium-conductive LiNbO_(3) coated high-voltage LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode with enhanced rate and cyclability

LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523) cathode materials can operate at extremely high voltages and have exceptional energy density.However,their use is limited by inherent structure instability during charge/discharge and exceptionally oxidizing Ni^(4+)at the surface.Herein,we have developed a citrate-assisted deposition concept to achieve a uniform lithium-conductive LiNbO_(3) coating layer on the NCM523 surface that avoids self-nucleation of Nb-contained compounds in solution reaction.The electrode-electrolyte interface is therefore stabilized by physically blocking the detrimental parasitic reactions and Ni^(4+)dissolution whilst still maintaining high Li+conductivity.Consequently,the modified NCM523 exhibits an encouraging Li-storage specific capacity of 207.4 m Ah g-1at 0.2 C and 128.9 m Ah g-1 at 10 C over the range 3.0-4.5 V.Additionally,a 92% capacity retention was obtained after 100 cycles at 1 C,much higher than that of the pristine NCM523(73%).This surface engineering strategy can be extended to modify other Ni-rich cathode materials with durable electrochemical performances.

From bibliometric analysis: 3D printing design strategies and battery applications with a focus on zinc‐ion batteries

Three‐dimensional(3D)printing has the potential to revolutionize the way energy storage devices are designed and manufactured.In this paper,we explore the use of 3D printing in the design and production of energy storage devices,especially zinc‐ion batteries(ZIBs)and examine its potential advantages over traditional manufacturing methods.3D printing could significantly improve the customization of ZIBs,making it a promising strategy for the future of energy storage.In particular,3D printing allows for the creation of complex,customized geometries,and designs that can optimize the energy density,power density,and overall performance of batteries.Simultaneously,we discuss and compare the impact of 3D printing design strategies based on different configurations of film,interdigitation,and framework on energy storage devices with a focus on ZIBs.Additionally,3D printing enables the rapid prototyping and production of batteries,reducing leading times and costs compared with traditional manufacturing methods.However,there are also challenges and limitations to consider,such as the need for further development of suitable 3D printing materials and processes for energy storage applications.

From lab to market:a review of commercialization and advances for binders in lithium-,zinc-,sodium-ion batteries

The paper discusses the progress and commercialization of binders for energy storage applications,such as batteries.It explains the role of binders in holding together active materials and current collectors,and highlights the challenges associated with conventional organic solvents in binders.The potential of aqueous binders is introduced as a cost-effective and environmentally friendly alternative.The advantages and limitations of different types of binders are discussed,and the importance of binder selection for optimal battery performance is emphasized.The current state of commercialization of binders is reviewed,and the need for collaboration between researchers,manufacturers,and policymakers to develop and promote environmentally friendly and cost-effective binders is emphasized.The paper concludes by outlining future directions for research and development to further improve the performance and commercialization of binders,while addressing limitations such as lack of standardization,high cost,and long-term stability and reliability.

Supersaturated bridge-sulfur and vanadium co-doped MoS_(2) nanosheet arrays with enhanced sodium storage capability

The low specific capacity and sluggish electrochemical reaction kinetics greatly block the development of sodium-ion batteries(SIBs).New high-performance electrode materials will enhance development and are urgently required for SIBs.Herein,we report the preparation of supersaturated bridge-sulfur and vanadium co-doped MoS2 nanosheet arrays on carbon cloth(denoted as V-MoS_(2+x)/CC).The bridge-sulfur in M0S2 has been created as a new active site for greater Na^(+)storage.The vanadium doping increases the density of carriers and facilitates accelerated electron transfer.The synergistic dual-doping effects endow the V-MoS_(2+x)/CC anodes with high sodium storage performance.The optimized V-MoS_(2.49)/CC gives superhigh capacities of 370 and 214 mAh·g^(-1)at 0.1 and 10 A·g^(-1)within 0.4-3.0 V,respectively.After cycling 3,000 times at 2 A·g^(-1),almost 83%of the reversible capacity is maintained.The findings indicate that the electrochemical performances of metal sulfides can be further improved by edge-engineering and lattice-doping co-modification concept.

锌在正极材料上的欠电位沉积:水系锌离子电池中的一种可避免的衰减机理

水系锌离子电池由于其低成本、高安全、高容量等特点,在大规模储能方面极具应用前景.然而其实际应用严重受限于其较差的循环寿命.本文揭示了正极材料上的锌金属的欠电位沉积现象,该反应具有高度的不可逆性,导致水系锌离子电池性能衰减.结合实验和理论模拟方法,揭示出该欠电位沉积过程符合二维成核和生长模型,在热力学上是一种可行的机制.此外,发现该现象广泛存在于VO_(2)//Zn、TiO_(2)//Zn和SnO_(2)//Zn等体系中.通过控制电池的电压区间下限,显著地消除了正极上的锌欠电位沉积,缓解了电池的退化.本工作为水系锌离子电池的性能衰减提供了新的见解,并启发电池研究者关注电池体系中的金属欠电位沉积现象.

原位构筑富异质结界面的双金属硫/磷化合物提升水系锌电池性能

目前开发高倍率和稳定的水系锌离子电池电极材料仍然是一个挑战.本研究提出了一种磷化辅助界面工程策略,将NiCo_(2)S_(4)纳米片可控转化为NiCoP/NiCo_(2)S_(4)异质结构作为水系锌离子电池电极材料.具有丰富界面的多组分异质结构不仅提高了电极材料的电导率,而且增强了锌离子的扩散路径.和预期结果一样,NiCoP/NiCo_(2)S_(4)电极材料在10 A g^(−1)的电流密度下其容量高达251.1 mA h g^(−1),且具有优异的倍率性能(电流密度高达50 A g^(−1)时,其容量保持约为76%).此外,以NiCoP/NiCo_(2)S_(4)为正极组装的锌离子电池也展现了优异的比容量(在5 A g^(−1)的电流密度下高达265.1 mA h g^(−1)),长循环稳定性(经过5000圈循环后比容量保持率为96.9%)和高能量密度(在8.4 kW kg^(−1)的功率密度下高达444.7 W h kg^(−1)).因此,本研究为构建具有丰富界面的异质结电极材料提供了一种简单的磷化辅助界面工程策略,为未来开发高性能储能器件提供了理论基础.

Sodium Superionic Conductors(NASICONs)as Cathode Materials for Sodium‑Ion Batteries

Sodium-ion batteries(SIBs)have developed rapidly owing to the high natural abundance,wide distribution,and low cost of sodium.Among the various materials used in SIBs,sodium superion conductor(NASICON)-based electrode materials with remarkable structural stability and high ionic conductivity are one of the most promising candidates for sodium storage electrodes.Nevertheless,the relatively low electronic conductivity of these materials makes them display poor electrochemical performance,significantly limiting their practical application.In recent years,the strategies of enhancing the inherent conductivity of NASICON-based cathode materials have been extensively studied through coating the active material with a conductive carbon layer,reducing the size of the cathode material,combining the cathode material with various carbon materials,and doping elements in the bulk phase.In this paper,we review the recent progress in the development of NASICON-based cathode materials for SIBs in terms of their synthesis,characterization,functional mechanisms,and performance validation/optimization.The advantages and disadvantages of such SIB cathode materials are analyzed,and the relationship between electrode structures and electrochemical performance as well as the strategies for enhancing their electrical conductivity and structural stability is highlighted.Some technical challenges of NASICON-based cathode materials with respect to SIB performance are analyzed,and several future research directions are also proposed for overcoming the challenges toward practical applications.

可溶性多孔有机笼作为均质剂与电子受体:实现多相合金纳米颗粒催化剂的均质化和高性能化

开发能够保持表面活性并稳定分散的超细合金纳米颗粒(<5 nm)用于多相催化已受到广泛关注,并具有极大的挑战性.本文提出有机分子笼限域策略,并成功制备了手性共价亚胺笼空腔“禁锢”超细铂铑合金纳米颗粒(PtRh@RCC3)的纳米复合材料.其中,可溶性RCC3可以作为均质剂,使溶液中的多相铂铑合金均质化.此外,X射线吸收近边结构结果表明:RCC3还可以作为电子受体从铂原子中提取电子,从而形成更高价的铂原子,这有利于提高4-硝基苯酚还原的催化活性,由于铂、铑原子的协同作用和RCC3的独特功能,Pt_(1)Rh_(16)@RCC3对4-硝基苯酚的催化还原反应速率常数分别是Pt_(1)Rh_(16)块体、Pt@RCC3和Rh@RCC3的49.6、8.2和5.5倍.该工作为溶液中均质化合金纳米颗粒多相催化剂提供了一种可行的策略,在先进的催化应用领域表现出巨大的潜力.