CoS Nanosheets Coated with Dopamine-Derived Carbon Standing on Carbon Fiber Cloth as Binder-Free Anode for Li-ion Batteries

Cobalt sulphides attract much attention as anode materials for Li-ion batteries(LIBs).However,its poor conductivity,low initial column efficiency and large volume changes during cycling have hindered its further development.Herein,novel interlaced CoS nanosheets were firstly prepared on Carbon Fiber Cloth(CFC)by two hydrothermal reactions followed with carbon coating via carbonizing dopamine(CoS NS@C/CFC).As a freestanding anode,the nanosheet structure of CoS not only accommodates the volume variation,but also provides a large interface area to proceed the charge transfer reaction.In addition,CFC works as both a three-dimensional skeleton and an active substance which can further improve the areal capacity of the resulting electrode.Furthermore,the coated carbon combined with the CFC work as a 3D conductive network to facilitate the electron conduction.The obtained CoS NS@C/CFC,and the contrast sample prepared with the same procedure but without carbon coating(CoS NS/CFC),are characterized with XRD,SEM,TEM,XPS and electrochemical measurements.The results show that the CoS NS@C/CFC possesses much improved electrochemical performance due to the synergistic effect of nanosheet CoS,the coated carbon and the CFC substrate,exhibiting high initial columbic efficiency(~87%),high areal capacity(2.5 at 0.15 mA cm−2),excellent rate performance(1.6 at 2.73 mA cm−2)and improved cycle stability(87.5%capacity retention after 300 cycles).This work may provide a new route to explore freestanding anodes with high areal specific capacity for LIBs.

Influence of carbon sources on the performance of carbon-coated nano-silicon

Silicon-based material is an important anode material for next-generation lithium-ion batteries.In order to overcome its shortcomings,carbon coating is often employed to improve the electrochemical performance.However,the carbon source,carbon content,and different contact and mixing schemes between carbon sources and silicon are all complex factors and need to be clarified.In this study,nano-silicon is coated by the chemical vapor deposition method using different carbon sources,such as acetylene,methane,propane,and propylene.Carbon content after coating is designed to stay at the same level to reduce the experimental error.Results show the sample with higher conductivity provides higher cycle performance.Propylene is the best choice of the four carbon sources studied in this work.These results indicate that the selection of the carbon source is an important factor that plays a significant role in electrochemical performance.

Carbon-coated ZnO Nanocomposite Microspheres as Anode Materials for Lithium-ion Batteries

The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method.The effect of carbon content on the microstructure,morphology and electrochemical performance of the materials was investigated by XRD,Raman spectroscopy,transmission electron microscopy,scanning electron microscopy and electrochemical techniques.Research results show that the spherical ZnO/C material with a carbon cladding content of 10%is very homogeneous and approximately 200 nm in size.The electrochemical performances of the ZnO/C nanospheres as an anode materials are examines.The ZnO/C exhibits better stability than pure ZnO,excellent lithium storage properties as well as improved circulation performance.The Coulomb efficiency of the ZnO/C with 10%carbon coated content reaches 98%.The improvement of electrochemical performance can be attributed to the carbon layer on the ZnO surface.The large volume change of ZnO during the charge-discharge process can be effectively relieved.

Preparation and electrochemical lithium storage performance of porous silicon microsphere composite with metal modification and carbon coating

This work adopts a multi⁃step etching⁃heat treatment strategy to prepare porous silicon microsphere com⁃posite with Sb⁃Sn surface modification and carbon coating(pSi/Sb⁃Sn@C),using industrial grade SiAl alloy micro⁃spheres as a precursor.pSi/Sb⁃Sn@C had a 3D structure with bimetallic(Sb⁃Sn)modified porous silicon micro⁃spheres(pSi/Sb⁃Sn)as the core and carbon coating as the shell.Carbon shells can improve the electronic conductivi⁃ty and mechanical stability of porous silicon microspheres,which is beneficial for obtaining a stable solid electrolyte interface(SEI)film.The 3D porous core promotes the diffusion of lithium ions,increases the intercalation/delithia⁃tion active sites,and buffers the volume expansion during the intercalation process.The introduction of active met⁃als(Sb⁃Sn)can improve the conductivity of the composite and contribute to a certain amount of lithium storage ca⁃pacity.Due to its unique composition and microstructure,pSi/Sb⁃Sn@C showed a reversible capacity of 1247.4 mAh·g^(-1) after 300 charge/discharge cycles at a current density of 1.0 A·g^(-1),demonstrating excellent rate lithium storage performance and enhanced electrochemical cycling stability.

Performance of activated carbon coated graphite bipolar electrodes on capacitive deionization method for salinity reduction

This research investigates a capacitive deionization method for salinity reduction in a batch reactor as a new approach for desalination.Reductions of cost and energy compared with conventional desalination methods are the significant advantages of this approach.In this research,experiments were performed with a pair of graphite bipolar electrodes that were coated with a one-gram activated carbon solution.After completing preliminary tests,the impacts of four parameters on electrical conductivity reduction,including(1)the initial concentration of feed solution,(2)the duration of the tests,(3)the applied voltage,and(4)the pH of the solution,were examined.The results show that the maximum efficiency of electrical conductivity reduction in this laboratory-scale reactor is about 55%.Furthermore,the effects of the initial concentration of feed solution are more significant than the other parameters.Thus,using the capacitive deionization method for water desalination with low and moderate salt concentrations(i.e.,brackish water)is proposed as an affordable method.Compared with conventional desalination methods,capacitive deionization is not only more efficient but also potentially more environmentally friendly.

Aromatic Carbon Coated Tin Composites as Anode Materials for Lithium Ion Batteries

Aromatic carbon coated tin composites（A/Sn） have been prepared by thermal decomposition of the stannous 1,8-naphthalenedicarboxylate precursors,which is a reformative preparation method.Sugar carbon coated tin composites（S/Sn） also are prepared as a contrast with the A/Sn composites.The morphology and composition of the products were characterized by Scanning Electricity Microscopy（SEM） and X-Ray Diffraction（XRD）.Their electrochemical performance as anode materials for lithium ion batteries were investigated;the results indicated that these materials exhibited good performance,and the cycle stability of A/Sn composites is especially superior to the S/Sn composites due to its special carbon resource.

Carbon-coated manganese dioxide nanoparticles and their enhanced electrochemical properties for zinc-ion battery applications

In this study, we report the cost-effective and simple synthesis of carbon-coated α-MnOnanoparticles(α-MnO@C) for use as cathodes of aqueous zinc-ion batteries(ZIBs) for the first time. α-MnO@C was prepared via a gel formation, using maleic acid(CHO) as the carbon source, followed by annealing at low temperature of 270 °C. A uniform carbon network among the α-MnOnanoparticles was observed by transmission electron microscopy. When tested in a zinc cell, the α-MnO@C exhibited a high initial discharge capacity of 272 m Ah/g under 66 m A/g current density compared to 213 m Ah/g, at the same current density, displayed by the pristine sample. Further, α-MnO@C demonstrated superior cycleability compared to the pristine samples. This study may pave the way for the utilizing carbon-coated MnOelectrodes for aqueous ZIB applications and thereby contribute to realizing high performance eco-friendly batteries.

Preparation and electrochemical properties of carbon-coated LiFePO_4 hollow nanofibers

Carbon-coated LiFePO_4 hollow nanofibers as cathode materials for Li-ion batteries were obtained by coaxial electrospinning. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area analysis, galvanostatic charge–discharge, and electrochemical impedance spectroscopy（EIS） were employed to investigate the crystalline structure, morphology, and electrochemical performance of the as-prepared hollow nanofibers. The results indicate that the carbon-coated LiFePO_4 hollow nanofibers have good long-term cycling performance and good rate capability： at a current density of 0.2C（1.0C = 170 mA ·g^-1） in the voltage range of 2.5–4.2 V, the cathode materials achieve an initial discharge specific capacity of 153.16 mA h·g^-1 with a first charge–discharge coulombic efficiency of more than 97%, as well as a high capacity retention of 99% after 10 cycles; moreover, the materials can retain a specific capacity of 135.68 mA h·g^-1, even at 2C.

Electrochemical properties of carbon-coated LiFePO_4 and LiFe_(0.98)Mn_(0.02)PO_4 cathode materials synthesized by solid-state reaction

Olivine structured LiFePO 4 /C (lithium iron phosphate) and Mn 2+ -doped LiFe 0.98 Mn 0.02 PO 4 /C powders were synthesized by the solid-state reaction. The effects of manganese partial substitution and different carbon content coating on the surface of LiFePO 4 were considered. The structures and electrochemical properties of the samples were measured by X-ray diffraction (XRD), cyclic voltammetry (CV), charge/discharge tests at different current densities, and electrochemical impedance spectroscopy (EIS). The electrochemical properties of LiFePO 4 cathodes with x wt.% carbon coating (x= 3, 7, 11, 15) at =0.2C, 2C (1C= 170 mAh·g 1 ) between 2.5 and 4.3 V were investigated. The measured results mean that the LiFePO 4 with 7 wt.% carbon coating shows the best rate performance. The discharge capacity of LiFe 0.98 Mn 0.02 PO 4 /C composite is found to be 165 mAh·g 1 at a discharge rate, = 0.2C, and 105 mAh·g 1 at =2C, respectively. After 10 cycles, the discharge capacity has rarely fallen, while that of the pristine LiFePO 4 /C cathode is 150 mAh·g 1 and 98 mAh·g 1 at =0.2 and 2C, respectively. Compared to the discharge capacities of both electrodes above, the evident improvement of the electrochemical performance is observed, which is ascribed to the enhancement of the electronic conductivity and diffusion kinetics by carbon coating and Mn 2+-substitution.

Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

Cobalt ferrite nanoparticles（CFNPs） were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition（TCVD）. In this process, acetylene gas（C2H2） was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750℃. The Ar/C2H2 ratio was 10：1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples＇ magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond-like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

Fabrication and properties of silver-based composites reinforced with carbon-coated Ti_(3)AlC_(2)

Ti_(3)AlC_(2)-reinforced Ag-based composites,which are used as sliding current collectors,electrical contacts,and electrode materials,exhibit remarkable performances.However,the interfacial reactions between Ag and Ti_(3)AlC_(2) significantly degrade the electrical and thermal properties of these composites.To diminish these interfacial reactions,we fabricated carbon-coated Ti_(3)AlC_(2) particles(C@Ti_(3)AlC_(2))as reinforcement and prepared Ag–10wt%C@Ti_(3)AlC_(2) composites with carbon-layer thicknesses ranging from 50–200 nm.Compared with the uncoated Ag–Ti_(3)AlC_(2) composite,Ag–C@Ti_(3)AlC_(2) was found to have a better distribution of Ti_(3)AlC_(2) particles.With increases in the carbon-layer thickness,the Vickers hardness value and relative density of Ag–C@Ti_(3)AlC_(2) gradually decreases.With a carbon-layer thickness of 150 nm,we obtained the lowest resistivity of Ag–C@Ti_(3)AlC_(2) of 29.4135.5×10^(−9)Ω·m,which is half that of Ag–Ti_(3)AlC_(2)(66.7×10^(−9)Ω·m).The thermal conductivity of Ag–C@Ti_(3)AlC_(2) reached a maximum value of 135.5 W·m^(−1)·K^(−1) with a 200-nm carbon coating(~1.8 times that of Ag–Ti_(3)AlC_(2)).These results indicate that the carbon-coating method is a feasible strategy for improving the performance of Ag–C@Ti_(3)AlC_(2) composites.

Carbon-Coated-Nylon-Fiber-Reinforced Cement Composites as an Intrinsically Smart Concrete for Damage Assessment during Dynamic Loading

Concrete containing short carbon-coated-nylon fibers (0.4-2.0 vol. pct) exhibited quasi-ductile response by developing a large damage zone prior to fracture localization. In the damage zone, the material was microcracked but continued to local strain-harden. The carbon-coated-nylon-fiber-reinforced concrete composites (NFRC) were found to be an intrinsically smart concrete that could sense elastic and inelastic deformation, as well as fracture. The fibers served to bridge the cracks and the carbon coating gave the conduction path. The signal provided came from the change in electrical resistance, which was reversible for elastic deformation and irreversible for inelastic deformation and fracture. The resistance decrease was due to the reduction of surface touch resistance between fiber and matrix and the crack closure. The resistance irreversible increase resulted from the crack opening and breakage of the carbon coating on nylon fiber.

Low Temperature Preparation of Carbide Coated Carbon for Refractory Castable Applications

Titanium carbide （ TiC ） coated graphite flakes （GF） and carbon black （CB） powders were prepared at relatively low temperatures （ 750 - 950 ℃ ） using a no- vel molten salt synthesis technique. The in-situ formed TiC coatings were homogeneous and crack-free and their thicknesses could be readily controlled/tailored by simply adjusting the Ti/C ratio. Compared to their uncoated counterparts, as prepared TiC coated GF and CB showed much improved water-wettability/dispersivity and rheological properties, and thus could be potentially used to prepare carbon-containing refractory castables.

In-Situ Corrosion Monitoring of Scratched Epoxy Coated Carbon Steel in Saturated Ca(OH)2 with or without 3% NaCl by Scanning Electrochemical Microscopy and Electrochemical Impedance Spectroscopy

The present work is investigated the in-situ monitoring of local corrosion process of scratched epoxy coated carbon steel in saturated Ca(OH)2 with and without 3% NaCl using SECM and correlated with EIS. The results obtained from EIS analysis showed that the corrosion resistance of scratched epoxy coated carbon steel decreases in Cl- containing solution as the increase in wet/ dry corrosion cycles. This was indicated by decrease in film resistance (Rf) and charge transfer resistance (Rct), while the coated steel maintain the resistance values in saturated Ca(OH)2, most of which recovered after drying. The corrosion process was monitored using SECM by setting the tip potential at -0.70 V vs Ag/AgCl, where the consumption of dissolved oxygen occurred at the surface of test sample. The consumption of dissolved oxygen current (I’oxy-c) values was increased during the immersion in a solution with 3% NaCl. However, in wet/dry corrosion cycles, I’oxy-c was decreased due to the coverage of hydroxides/oxides at scratch area which suppressed the consumption of dissolved O2. It was found that the continuous decrease in corrosion was mainly attributed to continuous formation of corrosion products at anodic spots.

Current collectors’ effects on the electrochemical performance of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) suspension electrodes for lithium slurry battery

Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density, while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors (CCs) are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance (Re) between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black (KB) slurry without active material (AM) and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.

Constructing a stable interface on Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode via lactic acid-assisted engineering strategy

Ni-rich layered oxides are potential cathode materials for next-generation high energy density Li-ion batteries due to their high capacity and low cost.However,the inherently unstable surface properties,including high levels of residual Li compounds,dissolution of transition metal cations,and parasitic side reactions,have not been effectively addressed,leading to significant degradation in their electrochemical performance.In this study,we propose a simple and effective lactic acid-assisted interface engineering strategy to regulate the surface chemistry and properties of Ni-rich LiNi_(0.8)Co_(0.1)Mr_(0.1)O_(2) cathode.This novel surface treatment method successfully eliminates surface residual Li compounds,inhibits structural collapse,and mitigates cathode-electrolyte interface film growth.As a result,the lactic acidtreated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) achieved a remarkable capacity retention of 91.7% after 100 cycles at 0.5 C(25℃) and outstanding rate capability of 149.5 mA h g^(-1) at 10 C,significantly outperforming the pristine material.Furthermore,a pouch-type full cell incorporating the modified LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode demonstrates impressive long-term cycle life,retaining 81.5% of its capacity after 500 cycles at 1 C.More importantly,the thermal stability of the modified cathode is also dramatically improved.This study offers a valuable surface modification strategy for enhancing the overall performance of Ni-rich cathode materials.

Influence of carbon coating prepared by microwave pyrolysis on properties of LiNi_(1/3) Mn_(1/3) Co_(1/3) O_2

A novel synthesis method of carbon-coated LiNil/3Mnl/3COl/302 cathode material for lithium-ion battery was reported. The carbon coating was produced from a precursor, glucose, by microwave-pyrolysis method. The prepared powders were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, X-ray fluorescence （XRF） and charge/discharge tests. XRD results indicate that the carbon coating does not change the phase structure of LiNil/3Mnl/3C01/302 material. SEM results show that the surface of spherical carbon-coated material becomes rough. Electrochemical performance results show that the carbon coating can improve the cycling performance of LiNii/3Mnl/3C01/302. The specific discharge capacity retention of the carbon-coated LiNi1/3Mnt/3Col/30z reached 85.0%-96.0% at the 50th cycle at 0.2C rate, and the specific discharge capacity retention is improved at a high rate.

Properties of hydrophobic carbon-PTFE composite coating with high corrosion resistance by facile preparation on pure Ti

Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and corrosion properties of the composite coatings were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), water contact angle method, X-ray photoelectron spectroscopy(XPS) and electrochemical technique, respectively. The effect of PTFE content on the corrosion properties of the composite coatings was studied. It is found that the composite coating film exhibits a full coverage with uniformly distributed PTFE when 0.1 mol/L of glucose is used as carbon source and 20 wt.% PTFE suspension as impregnating solution. The coating with 20 wt.% PTFE has a good bonding strength with Ti plate and exhibits excellent hydrophobic property with a water contact angle of 142.3° as well as superior corrosion resistance with corrosion current density as low as 0.0045 μA/cm^2. With regard to its excellent hydrophobicity and corrosion resistance, the carbon-PTFE composite coating may find potential application in automobiles and metal corrosion industries.

Corrosion performance and tribological behavior of diamond-like carbon based coating applied on Ni−Al−bronze alloy

The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.

Porous Microspheres Comprising CoSe2 Nanorods Coated with N-Doped Graphitic C and Polydopamine-Derived C as Anodes for Long-Lived Na-Ion Batteries

Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte system.The microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume stress.Consequently,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life stability.For instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.