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.

Hybrid Ni_(2)P/CoP Nanosheets as Efficient and Robust Electrocatalysts for Domestic Wastewater Splitting

The development of low-cost,robust and efficient non-noble metal electrocatalysts is still a pursuit for the hydrogen evolution reaction(HER).Herein,a self-standing electrocatalyst,Ni_(2)P/CoP nanosheet,was fabricated directly on three-dimensional Ni foams by two facile steps,which illustrated both high activity and stability for HER in different electrolytes.Benefiting from the porous structures of nanosheets with large specific surface area and the hybrid Ni_(2)P/CoP,the as-prepared electrocatalyst presented remarkable HER with overpotentials of 65.2 and 87.8 mV to reach a current density of-10 mA cm^(-2)in neutral and alkaline media,respectively.Density function theory calculations revealed a lower activation energy of water dissociation and efficient HER steps of hybrid Ni_(2)P/CoP nanosheets compared with mono CoP.The self-standing electrocatalyst maintained excellent chemical stability.Additionally,the HER process in domestic wastewater was realized with more impressive performance by using Ni_(2)P/CoP nanosheets compared with commercial Pt/C.Hydrogen was continuously generated for 20 h in mildly alkaline dishwashing wastewater.This work provides a feasible way to fabricate non-noble metal and self-standing hybrid bimetallic phosphides for HER in neutral and alkaline media,showing great potential for efficient hydrogen production by re-utilizing wastewater resources.

All-fluorinated electrolyte for non-flammable batteries with ultra-high specific capacity at 4.7 V

Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific capacity.Here,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal batteries.The electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode side.Therefore,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.

Nanodiamond-Assisted High Performance Lithium and Sodium Ions Co-Storage

While lithium resources are scarce for high energy-dense lithium-ion batteries(LIBs),sodium-ion batteries(SIBs),serving as an alternative,inherently suffer from low capacity and the high-cost use of non-graphite anodes.Combining Li-and Na-ions within a single battery system is expected to mitigate the shortcomings of both systems while leveraging their respective advantages.In this study,we developed and assembled a nanodiamonds(NDs)-assisted co-Li/Na-ion battery(ND–LSIB).This innovative battery system comprised a commercial graphite anode,an ND-modified polypropylene(DPP)separator,a hybrid lithium/sodium-based electrolyte,and a cathode.It is theoretically and experimentally demonstrated that the ND/Li co-insertion can serve as an ion-drill opening graphite layers and reconstructing graphite anodes into few-layered graphene with expanding interlayer space,achieving highly efficient Li/Na storage and the theoretical maximum of LiC_(6)for Li storage in graphite.In addition,ND is helpful for creating a LiF-/NaF-rich hybrid solid electrolyte interface with improved ionic mobility,mechanical strength,and reversibility.Consequently,ND–LSIBs have higher specific capacities~1.4 times the theoretical value of LIBs and show long-term cycling stability.This study proposes and realizes the concept of Li/Na co-storage in one ion battery with compatible high-performance,cost-effectiveness,and industrial prospects.

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.

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.

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.

Fe nanoclusters anchored in biomass waste-derived porous carbon nanosheets for high-performance supercapacitor

Metal-nanocluster materials have gradually become a promising electrode candidate for supercapaci-tor application.The high-efficient and rational architecture of these metal-nanocluster electrode mate-rials with satisfied supercapacitive performance are full of challenges.Herein,Fe-nanocluster anchored porous carbon(FAPC)nanosheets were constructed through a facile and low-cost impregnation-activation strategy.Various characterization methods documented that FAPC nanosheets possessed a mesopore-dominated structure with large surface area and abundant Fe-N4 active sites,which are crucial for su-percapacitive energy storage.The optimal FAPC electrode exhibited a high specific capacitance of 378 F/g at a specific current of 1 A/g and an excellent rate capability(271 F/g at 10 A/g),which are comparable or even superior to that of most reported carbon candidates.Furthermore,the FAPC-based device achieved a desired specific energy of 14.8 Wh/kg at a specific power of 700 W/kg.This work opens a new avenue to design metal-nanocluster materials for high-performance biomass waste-based supercapacitors.

Metal–organic frameworks and their derivatives for optimizing lithium metal anodes

Lithium metal anodes(LMAs)have been considered the ultimate anode materials for next-generation batteries.However,the uncontrollable lithium dendrite growth and huge volume expansion that can occur during charge and discharge seriously hinder the practical application of LMAs.Metal–organic framework(MOF)materials,which possess the merits of huge specific surface area,excellent porosity,and flexible composition/structure tunability,have demonstrated great potential for resolving both of these issues.This article first explores the mechanism of lithium dendrite formation as described by four influential models.Subsequently,based on an in-depth understanding of these models,we propose potential strategies for utilizing MOFs and their derivatives to suppress lithium dendrite growth.We then provide a comprehensive review of research progress with respect to various applications of MOFs and their derivatives to suppress lithium dendrites and inhibit volume expansion.The paper closes with a discussion of perspectives on future modifications of MOFs and their derivatives to achieve stable and dendrite-free lithium metal batteries.

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.

Fe-Co-Ni ternary single-atom electrocatalyst and stable quasi-solidelectrolyte enabling high-efficiency zinc-air batteries

The non-noble metal(Fe,Co,Ni,etc.)catalysts possess promising potential to replace noble metals(e.g.,Pt,Ru,Ir,etc.)as catalysts for oxygen electrocatalysis.Up to now,various mono-and dual-single-atom catalysts have been fabricated,though it is still challenging to synthesise ternary single-atom catalysts due to the difference of interaction forces between different metal ions(Fe,Co,Ni,etc.)and ligands.Here,we report a Fe-Co-Ni ternary single-atom catalyst(FeCoNi-Nx)derived from a zeolitic imidazolate frameworks(ZIF)precursor as an efficient oxygen electrocatalyst,and an optimised flexible casting-drying polyvinyl alcohol(CD-PVA)film as a quasi-solid electrolyte host,for high-efficiency solid-state Zn-air batteries.The aberration-corrected HAADF-STEM and EELS spectrum confirm the co-existence of Fe,Co and Ni single atoms in the FeCoNi-Nx catalyst,and the electrochemical,mechanical,and durability tests prove the superiority of the CD-PVA film.As a result,the FeCoNi-Nx-based rechargeable Zn-air battery delivers superior specific capacity(846.8 mAh·gZn-1)and power density(135 mW·cm^(-2))in aqueous electrolyte,as well as an over 60 mW·cm^(-2)power density in quasi-solid electrolyte.As a result,the quasi-solid-state Zn-air battery with a small area of only 2 cm2 is able to charge a mobile phone,which outperforms all the reported devices to date.

In situ construction of heterostructured bimetallic sulfide/phosphide with rich interfaces for high-performance aqueous Zn-ion batteries

It is still challenging to develop suitable cathode structures for high-rate and stable aqueous Zn-ion batteries.Herein,a phosphating-assisted interfacial engineering strategy is designed for the controllable conversion of NiCo_(2)S_(4) nanosheets into heterostructured NiCoP/NiCo_(2)S_(4) as the cathodes in aqueous Zn-ion batteries.The multicomponent heterostructures with rich interfaces can not only improve the electrical conductivity but also enhance the diffusion pathways for Zn-ion storage.As expected,the NiCoP/NiCo_(2)S_(4) electrode has high performance with a large specific capacity of 251.1 mA h g^(−1) at a high current density of 10 A g^(−1) and excellent rate capability(retaining about 76%even at 50 A g^(−1)).Accordingly,the Zn-ion battery using NiCoP/NiCo_(2)S_(4) as the cathode delivers a high specific capacity(265.1 mA h g^(−1) at 5 A g^(−1)),a long-term cycling stability(96.9%retention after 5000 cycles),and a competitive energy density(444.7W h kg^(−1) at the power density of 8.4 kW kg^(−1)).This work therefore provides a simple phosphating-assisted interfacial engineering strategy to construct heterostructured electrode materials with rich interfaces for the development of high-performance energy storage devices in the future.

In-situ electrochemical modification of pre-intercalated vanadium bronze cathodes for aqueous zinc-ion batteries

Vanadium bronzes have been well-demonstrated as promising cathode materials for aqueous zinc-ion batteries. However, conventional single-ion pre-intercalated V_(4)O_(9)nearly reached its energy/power ceiling due to the nature of micro/electronic structures and unfavourable phase transition during Zn;storage processes. Here, a simple and universal in-situ anodic oxidation method of quasi-layered Ca V_(4)O_(9)in a tailored electrolyte was developed to introduce dual ions(Ca^(2+) and Zn^(2+)) into bilayer δ-V_(4)O_(9)frameworks forming crystallographic ultra-thin vanadium bronzes,Ca^(2+)Zn^(2+)V_(4)O_(9)·n H;O. The materials deliver transcendental maximum energy and power densities of 366 W h kg-1(478 m A h g^(-1)@ 0.2 A g^(-1)) and 6627 W kg-1(245 m A h g^(-1)@10 A g^(-1)), respectively, and the long cycling stability with a high specific capacity up to 205 m A h g^(-1)after 3000 cycles at10 A g^(-1). The synergistic contributions of dual ions and Ca^(2+) electrolyte additives on battery performances were systematically investigated by multiple in-/ex-situ characterisations to reveal reversible structural/chemical evolutions and enhanced electrochemical kinetics, highlighting the significance of electrolyte-governed conversion reaction process. Through the computational approach, reinforced “pillar” effects,charge screening effects and regulated electronic structures derived from pre-intercalated dual ions were elucidated for contributing to boosted charge storage properties.

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.

Soluble porous organic cages as homogenizers and electron-acceptors for homogenization of heterogeneous alloy nanoparticle catalysts with enhanced catalytic activity

The creation of ultrafine alloy nanoparticles(<5 nm) that can maintain surface activity and avoid aggregation for heterogeneous catalysis has received much attention and is extremely challenging.Here,ultrafine PtRh alloy nanoparticles imprisoned by the cavities of reduced chiral covalent imine cage(PtRh@RCC3) are prepared successfully by an organic molecular cage(OMC) confinement strategy,while the soluble RCC3 can act as a homogenizer to homogenize the heterogeneous PtRh alloy in solution.Moreover,the X-ray absorption near-edge structure(XANES) results show that the RCC3 can act as an electron-acceptor to withdraw electrons from Pt,leading to the formation of higher valence Pt atoms,which is beneficial to improving the catalytic activity for the reduction of 4-nitrophenol.Attributed to the synergistic effect of Pt/Rh atoms and the unique function of the RCC3,the reaction rate constants of Pt_(1)Rh_(16)@RCC3 are 49.6,8.2,and 5.5 times than those of the Pt_(1)Rh_(16)bulk,Pt@RCC3 and Rh@RCC3,respectively.This work provides a feasible strategy to homogenize heterogeneous alloy nanoparticle catalysts in solution,showing huge potential for advanced catalytic application.