Microstructure and abrasive wear behaviour of anodizing composite films containing Si C nanoparticles on Ti6Al4V alloy

Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.

ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures

As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly important.However,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature performance.The ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature applications.Electrochemical analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 C.The outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.

Pioneering the direct large-scale laser printing of flexible“graphenic silicon”self-standing thin films as ultrahigh-performance lithium-ion battery anodes

Recent technological advancements,such as portable electronics and electric vehicles,have created a pressing need for more efficient energy storage solutions.Lithium-ion batteries(LIBs)have been the preferred choice for these applications,with graphite being the standard anode material due to its stability.However,graphite falls short of meeting the growing demand for higher energy density,possessing a theoretical capacity that lags behind.To address this,researchers are actively seeking alternative materials to replace graphite in commercial batteries.One promising avenue involves lithiumalloying materials like silicon and phosphorus,which offer high theoretical capacities.Carbon-silicon composites have emerged as a viable option,showing improved capacity and performance over traditional graphite or pure silicon anodes.Yet,the existing methods for synthesizing these composites remain complex,energy-intensive,and costly,preventing widespread adoption.A groundbreaking approach is presented here:the use of a laser writing strategy to rapidly transform common organic carbon precursors and silicon blends into efficient“graphenic silicon”composite thin films.These films exhibit exceptional structural and energy storage properties.The resulting three-dimensional porous composite anodes showcase impressive attributes,including ultrahigh silicon content,remarkable cyclic stability(over 4500 cycles with∼40%retention),rapid charging rates(up to 10 A g^(-1)),substantial areal capacity(>5.1 mAh cm^(-2)),and excellent gravimetric capacity(>2400 mAh g^(-1) at 0.2 A g^(-1)).This strategy marks a significant step toward the scalable production of high-performance LIB materials.Leveraging widely available,cost-effective precursors,the laser-printed“graphenic silicon”composites demonstrate unparalleled performance,potentially streamlining anode production while maintaining exceptional capabilities.This innovation not only paves the way for advanced LIBs but also sets a precedent for transforming various materials into high-performing electrodes,promising reduced complexity and cost in battery production.

Effects of polyaniline on electrochemical properties of composite inert anodes used in zinc electrowinning

In order to search for a suitable anode material used in zinc electrowinning in place of Pb-Ag alloy,Al/Pb-PANI（polyaniline）-WC（tungsten carbide） composite inert anodes were prepared on aluminum alloy substrate by double pulse electrodeposition（DPE） of PANI and WC particles with Pb2＋ from an original plating bath.Thereafter,anodic polarization curves,cyclic voltammetry curves and Tafel polarization curves for the composite inert anodes obtained under different PANI concentrations in the original plating bath were measured,and the microstructural features were also investigated by scanning electron microscopy（SEM）.The results show that Al/Pb-PANI-WC composite inert anode obtained under PANI concentration of 20 g/L in the original plating bath possesses uniform microstructures and composition distributions,higher electrocatalytic activity,better reversibility of electrode reaction and corrosion resistance in a synthetic zinc electrowinning electrolyte of 50 g/L Zn2＋,150 g/L H2SO4 at 35 °C.Compared with Pb-1%Ag alloy,the overpotential of oxygen evolutions for the composite inert anode are decreased by 185 mV and 166 mV,respectively,under 500 A/m2 and 1000 A/m2.

Properties of a new type Al/Pb-0.3%Ag alloy composite anode for zinc electrowinning

An A1/Pb-0.3%Ag alloy composite anode was produced via composite casting. Its electrocatalytic activity for the oxygen evolution reaction and corrosion resistance was evaluated by anodic polarization curves and accelerated corro- sion test, respectively. The microscopic morphologies of the anode section and anodic oxidation layer during accelerated corrosion test were obtained by scanning electron microscopy. It is found that the composite anode （hard anodizing） dis- plays a more compact interracial combination and a better adhesive strength than plating tin. Compared with industrial Pb-0.3%Ag anodes, the oxygen evolution overpotentials of A1/Pb-0.3%Ag alloy （hard anodizing） and A1/Pb-0.3%Ag alloy （plating tin） at 500 A.m-2 were lower by 57 and 14 mV, respectively. Furthermore, the corrosion rates of Pb-0.3%Ag alloy, A1/Pb-0.3%Ag alloy （hard anodizing）, and A1/Pb-0.3%Ag alloy （plating tin） were 13.977, 9.487, and 11.824 g.m-2.h-1, respectively, in accelerated corrosion test for 8 h at 2000 A-m-2. The anodic oxidation layer of A1/Pb-0.3%Ag alloy （hard anodizing） is more compact than Pb-0.3%Ag alloy and A1/Pb-0.3%Ag alloy （plating tin） after the test.

Polar interaction of polymer host-solvent enables stable solid electrolyte interphase in composite lithium metal anodes

The lithium(Li) metal anode is an integral component in an emerging high-energy-density rechargeable battery.A composite Li anode with a three-dimensional(3 D) host exhibits unique advantages in suppressing Li dendrites and maintaining dimensional stability.However,the fundamental understanding and regulation of solid electrolyte interphase(SEI),which directly dictates the behavior of Li plating/stripping,are rarely researched in composite Li metal anodes.Herein,the interaction between a polar polymer host and solvent molecules was proposed as an emerging but effective strategy to enable a stable SEI and a uniform Li deposition in a working battery.Fluoroethylene carbonate molecules in electrolytes are enriched in the vicinity of a polar polyacrylonitrile(PAN) host due to a strong dipole-dipole interaction,resulting in a LiF-rich SEI on Li metal to improve the uniformity of Li deposition.A composite Li anode with a PAN host delivers 145 cycles compared with 90 cycles when a non-polar host is employed.Moreover,60 cycles are demonstrated in a 1:0 Ah pouch cell without external pressure.This work provides a fresh guidance for designing practical composite Li anodes by unraveling the vital role of the synergy between a 3 D host and solvent molecules for regulating a robust SEI.

Single-step Preparation of Nano-homogeneous NiO/YSZ Composite Anode for Solid Oxide Fuel Cells

Homogeneous co-precipitation and hydrothermal treatment were used to prepare nano- and highly dispersed Ni O/YSZ(yttria-stabilized zirconia) composite powders. Composite powders of size less than 100 nm were successfully prepared. This process did not require separate sintering of the YSZ and Ni O to be used as the raw materials for solid oxide fuel cells. The performance of a cell fabricated using the new powders(max.power density ~0.87 W/cm^2) was higher than that of a cell fabricated using conventional powders(max. power density ~0.73 W/cm^2). Co-precipitation and hydrothermal treatment proved to be very effective processes for reducing cell production costs as well as improving cell performance.

An α-Fe_(2)O_(3)/Circulating Fluidized Bed Fly Ash Based Geopolymer Composite Anode for Electrocatalytic Degradation of Indigo Carmine Dye Wastewater

Geopolymers have been developed to various catalysts due to their advantages.However,low conductivity restricts their application in the electrocatalysis field.In this study,anα-Fe_(2)O_(3)/circulating fluidized bed fly ash based geopolymer(CFAG)composite anode was fabricated using a facile dip-coating method by loadingα-Fe_(2)O_(3) in the matrix of CFAG.The effects ofα-Fe_(2)O_(3) content on the composition,surface morphology and electrochemical performance ofα-Fe_(2)O_(3)/CFAG composite anode were investigated.The X-ray diffraction(XRD)and scanning electron microscope(SEM)results demonstrated thatα-Fe_(2)O_(3) was successfully inlaid with the surface of amorphous CFAG matrix.The electrochemical measurements indicated thatα-Fe_(2)O_(3)/CFAG composite anode had higher oxygen evolution potential,greater electrochemical activity area,and smaller electrochemical impedance than CFAG.The as-prepared composite anode was applied for electrocatalytic degradation of indigo carmine dye wastewater.It was discovered that the highest degradation efficiency over 10α-Fe_(2)O_(3)/CFAG reached up 92.6%,and the degradation of indigo carmine followed pseudo-first-order kinetics.Furthermore,10α-Fe_(2)O_(3)/CFAG composite anode presented excellent stability after five cycles.The active hydroxyl radical was generated over theα-Fe_(2)O_(3)/CFAG composite anode,which acted as strong oxidizing agents in the electrocatalytic degradation process.

Development of High Efficient Composite Anodes

A new type of high efficient Ti composite anodes for electrodeposition of MnO 2 was successfully developed and was widely satisfied with production in many factories in China. The process parameters of electrolysis in using the composite anodes were optimized and discussed.

Properties of Al/Conductive Coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 Composite Anode for Zinc Electrowinning

The properties of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 composite anode for zinc electrowinning were investigated. The electrochemical performance was studied by Tafel polarization curves（Tafel）, electrochemical impedance spectroscopy（EIS） and corrosion rate obtained in an acidic zinc sulfate electrolyte solution. Scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and energy dispersive X-ray spectroscopy（EDXS） were used to observe the microstructural features of coating. Anodes of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-ZrO2, and Pb-1%Ag anodes were also researched. The results indicated that the Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 showed the best catalytic activity and corrosion resistant performance; the intensity of diffraction peak exhibited the highest value as well as a new PbWO4 phase; the content of WC and ZrO2 in coating showed the highest value as well as the finest grain size.

Rare Earth Application in Sealing Anodized Al-Based Metal Matrix Composites

A new method for corrosion protection of Al-based metal matrix composites (MMC) was developed using two-step process, which involves anodizing in H2SO4 solution and sealing in rare earth solution. Corrosion resistance of the treated surface was evaluated with polarization curves. The results showed that the effect of the protection using rare earth sealing is equivalent to that using chromate sealing for Al6061/SiCp. The rare earth metal salt can be an alternative to the toxic chromate for sealing anodized Al MMC.

Preparation and Properties of Al-Ni Composite Anodic Films on Aluminum Surface

Ni element was introduced to aluminum surface by a simple chemical immersion method, and A1-Ni composite anodic films were obtained by following anodizing. The morphology, structure and composition of the A1-Ni anodic films were examined by scanning electron microscopy （SEM）, energy disperse spectroscopy （EDS） and atomic force microscopy（AFM）. The electrochemical behaviors of the films were studied by means of polarization measurement and electrochemical impedance spectroscopy （EIS）. The experimental results show that the A1-Ni composite anodic film is more compact with smaller pore diameters than that of the A1 anodic film. The introduction of nickel increases the impedances of both the barrier layer and the porous layer of the anodic films. In NaC1 solutions, the A1-Ni composite anodic films show higher impedance values and better corrosion resistance.

Forging Inspired Processing of Sodium-Fluorinated Graphene Composite as Dendrite-Free Anode for Long-Life Na–CO_(2) Cells

Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling,while a facile method to solve this issue is still lacking.In this work,we report an effective,environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable,NaF-rich solid electrolyte interface(SEI)layer on metallic Na via adding a small amount(~3 wt%)of fluorinated graphene(FG)in bulk Na.Inspired by the forging processing,a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes.The Na/FG–Na/FG half cell exhibits a low voltage hysteresis of 110–140 mV over 700 h at a current density up to 5 mA cm^(-2) with an areal capacity as high as 5 mAh cm^(-2).Na–CO_(2) full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g^(-1).Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na.Both experiments and density functional theory(DFT)calculations confirm the formation of the NaF-rich SEI layer.The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.

Review on lithium metal anodes towards high energy density batteries

Lithium metal anode(LMA) is a promising candidate for achieving next-generation high-energy-density batteries due to its ultrahigh theoretical capacity and most negative electrochemical potential. However, the practical application of lithium metal battery(LMB) is largely retarded by the instable interfaces, uncontrolled dendrites, and rapid capacity deterioration. Herein, we present a comprehensive overview towards the working principles and inherent challenges of LMAs. Firstly, we diligently summarize the intrinsic mechanism of Li stripping and plating process. The recent advances in atomic and mesoscale simulations which are crucial in guiding mechanism study and material design are also summarized. Furthermore, the advanced engineering strategies which have been proved effective in protecting LMAs are systematically reviewed, including electrolyte optimization, artificial interface, composite/alloy anodes and so on. Finally, we highlight the current limitations and promising research directions of LMAs. This review sheds new lights on deeply understanding the intrinsic mechanism of LMAs, and calls for more endeavors to realize practical Li metal batteries.

Design and application of copper/lithium composite anodes for advanced lithium metal batteries

Lithium(Li)is a promising candidate for nextgeneration battery anode due to its high theoretical specific capacity and low reduction potential.However,safety issues derived from the uncontrolled growth of Li dendrite and huge volume change of Li hinder its practical application.C onstructing dendrite-free composite Li anodes can significantly alleviate the above problems.Copper(Cu)-based materials have bee n widely used as substrates of the composite electrodes due to their chemical stability,excellent conductivity,and good mechanical strength.Copper/lithium(Cu/Li)composite anodes significantly regulate the local current density and decrease Li nucleation overp otential,realizing the uniform and dendrite-free Li deposition.In this review,Cu/Li composite methods including electrodeposition,melting infusion,and mechanical rolling are systematically summarized and discussed.Additionally,design strategies of Cu-based current collectors for high performance Cu/Li composite anodes are illustrated.General challenges and future development for Cu/Li composite anodes are presented and postulated.We hope that this review can provide a comprehensive understanding of Cu/Li composite methods of the latest development of Li metal anode and stimulate more research in the future.

Optimization of two-dimensional solid-state electrolyte-anode interface by integrating zinc into composite anode with dual-conductive phases

Solid-state electrolytes(SSEs)are a solution to safety issues related to flammable organic electrolytes for Li batteries.Insufficient contact between the anode and SSE results in high interface resistance,thus causing the batteries to exhibit high charging and discharging overpotentials.Recently,we reduced the overpotential of Li stripping and plating by introducing a high proportion of dual-conductive phases into a composite anode.The current study investigates the interface resistance and stability of a composite electrode modified with Zn and a lower proportion of dual-conductive phases.Zn-cation-adsorbed Prussian blue is synthesized as an intermediate component for a Zn-modified composite electrode(Li-FeZnNC).The Li-FeZnNC symmetric cell presents a lower interface resistance and overpotential compared with Li-FeNC(without Zn modification)and Li-symmetric cells.The Li-FeZnNC symmetric cell shows high electrochemical stability during Li stripping and plating at different current densities and high stability for 200 h.Full batteries with a Li-FeZnNC composite anode,garnet-type SSE,and LiFePO4 cathode show low charging and discharging overpotentials,a capacity of 152 mAh g^(−1),and high stability for 200 cycles.

Status and challenges facing representative anode materials for rechargeable lithium batteries

Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.

Lithiophilic interface guided transient infiltration of molten lithium for stable 3D composite lithium anodes

Fabricating three-dimensional(3D)composite lithium anodes via thermal infusion effectively addresses uncontrollable Li deposition and large volume changes.However,potential risks due to the long wetting time and high melting point remain a critical yet unconsidered issue.Herein,we report a stable 3D composite Li anode by infusing molten Li into a 3D scaffold within 3 s at 220℃.The key-enabling technique is the growth of a lithiophilic Mg-Al double oxide(LDO)nanosheet array layer on the scaffold.The in-situ formed lithiophilic alloy,combined with the capillary forces from the nanosheet arrays,enabled the transient infiltration of molten Li.In addition,the formed high ionic-conductivity Li phase can help construct a robust solid electrolyte interphase(SEI),stabilize the Li anode/electrolyte interface,and guide uniform Li deposition.The 3D composite anode exhibited a long cycling life of 1,000 h under a current density of 1 mA·cm^(−2)and over 1,600 h under a current density of 2 mA·cm^(−2)with a high areal capacity of 4 mAh·cm^(−2)in Li/Li symmetric cells.The 3D composite anodes paired with high areal capacity LiFePO_(4)(LFP)and S cathodes demonstrate its practical application feasibility.

Solid-state corrosion of lithium for prelithiation of SiO_(x)-C composite anode with carbon-incorporated lithium phosphorus oxynitride

In order to address the issues of low initial Coulombic efficiency of SiO_(x)-C composite anode due to the formation of solid electrolyte interphase,irreversible conversion reaction,and large volume change,the prelithiation method using metal lithium has been employed as one of effective solutions.However,violent side reactions with liquid electrolyte for prelithiation lead to low prelithiation efficiency and induce poor interface between the SiO_(x)-C electrode and liquid electrolyte.Here,a new prelithiation method with so called solid-state corrosion of lithium is developed.By replacing liquid electrolyte with solid-state electrolyte of carbon-incorporated lithium phosphorus oxynitride(LiCPON),not only various side reactions associated with metal lithium are avoided,but also the perfect interface is achieved from the decomposition products of LiCPON.The successful implementation of solid-state corrosion prelithiation can be confirmed by changes in optical image,scanning electron microscopy,and X-ray diffraction.Compared with pristine electrode,the initial Coulombic efficiency of the prelithiated electrode using solid electrolyte can be increased by about 10%,reaching 98.6%in half cell and 88.9%in full cell.Compared with prelithiated electrode using liquid electrolyte,the prelithiation efficiency of the prelithiated anode with solid-state corrosion can be increased from 25.7%to 82.8%.Solid-state corrosion of lithium is expected to become a useful method for prelithiation of SiO_(x)-C composite electrode with high initial Coulombic efficiency and large prelithiation efficiency.

Effects of sintering temperature on microstructure and performance of Ti-based Ti-Mn alloy anodic material

A novel Ti-based Ti-Mn composite anode used for electrolytic manganese dioxide(EMD) fabrication was developed by a two-step heating manganizing technique.The effects of sintering temperature on the manganized microstructure and the performance of the composite anode were studied by scanning electron microscopy(SEM),mechanical properties tests at room temperature and electrochemical methods.The results show that the thickness of the diffusion layer increases with the increase of sintering temperature up to 1 100 °C;whereas,the surface Mn content increases and reaches the maximum at 1 000 °C and then decreases thereafter.Lower surface Mn content is beneficial for the enhanced corrosion resistance and lowered open cell voltage in electrolytic process.The new anode prepared under the optimized conditions has been applied in industry and exhibits superior economic benefits to conventional Ti anodic materials.