Amorphous Ag Research Articles

Controllable Silver Release for Efficient Treatment of Drug-Resistant Bacterial-Infected Wounds.

The use of traditional Ag-based antibacterial agents is usually accompanied by uncontrollable silver release, which makes it difficult to find a balance between antibacterial performance and biosafety. Herein, we prepared a core-shell system of ZIF-8-derived amorphous carbon-coated Ag nanoparticles (Ag@C) as an ideal research model to reveal the synergistic effect and structure-activity relationship of the structural transformation of carbon shell and Ag core on the regulation of silver release behavior. It is found that Ag@C prepared at 600 °C (AC6) exhibits the best ion release kinetics due to the combination of relatively simple shell structure and lower crystallinity of the Ag core, thereby exerting stronger antibacterial properties (>99.999 %) at trace doses (20 μg mL-1) compared with most other Ag-based materials. Meanwhile, the carbon shell prevents the metal Ag from being directly exposed to the organism and thus endows AC6 with excellent biocompatibility. In animal experiments, AC6 can effectively promote wound healing by inactivating drug-resistant bacteria while regulating the expression of TNF-α and CD31. This work provides theoretical support for the scientific design and clinical application of controllable ion-releasing antibacterial agents.

Ferromagnetic semiconductor EuO thin films characterized by vacuum electrochemical process with ionic liquid

In this study, the electrochemical impedance analysis was demonstrated for thin film EuO, a ferromagnetic semiconductor, by taking the advantage of our original instrument, which enables to perform the entire process from thin film deposition to electrochemical measurement with ionic liquid in a vacuum. Effects of whether surface protecting layers were insulative or metallic, as well as their thickness on the electrochemical measurement of EuO thin films were examined by comparing the choices of amorphous alumina and Ag metal as the protecting layer. As a result, the relative permittivity of EuO films, even with a thickness of 2 nm, was successfully estimated and the averaged value was 6.6 within an error of 10 %. Furthermore, the donor density accordingly estimated was found well correlated with the Curie temperature TC of the EuO films.

A Molecular Dynamics Study of Ag-Ni Nanometric Multilayers: Thermal Behavior and Stability.

Nanometric multilayers composed of immiscible Ag and Ni metals were investigated by means of molecular dynamics simulations. The semi-coherent interface between Ag and Ni was examined at low temperatures by analyzing in-plane strain and defect formation. The relaxation of the interface under annealing conditions was also considered. With increasing temperature, a greater number of atomic planes participated in the interface, resulting in enhanced mobility of Ag and Ni atoms, as well as partial dissolution of Ni within the amorphous Ag. To mimic polycrystalline layers with staggered grains, a system with a triple junction between a silver single layer and two grains of nickel was examined. At high temperatures (900 K and 1000 K), the study demonstrated grain boundary grooving. The respective roles of Ni and Ag mobilities in the first steps of grooving dynamics were established. At 1100 K, a temperature close but still below the melting point of Ag, the Ag layer underwent a transition to an amorphous/premelt state, with Ni grains rearranging themselves in contact with the amorphous layer.

Biosynthesis, Spectrophotometric Follow-Up, Characterization, and Variable Antimicrobial Activities of Ag Nanoparticles Prepared by Edible Macrofungi.

The biosynthesis of silver nanoparticles (Ag NPs) could play a significant role in the development of commercial antimicrobials. Herein, the biosynthesis of Ag NPs was studied using the edible mushroom Pleurotus floridanus, and following its formation, spectrophotometry was used to detect the best mushroom content, pH, temperature, and silver concentration. After that, the morphology was described via transmission electron microscopy (TEM), and nanoscale-size particles were found ranging from 11 to 13 nm. The best conditions of Ag content and pH were found at 1.0 mM and 11.0, respectively. In addition, the best mushroom extract concentration was found at 30 g/L. According to XRD analysis, the crystal structure of the formed amorphous Ag NPs is cubic with a space group of fm-3m and a space group number of 225. After that, the function groups at the surface of the prepared Ag NPs were studied via FTIR analysis, which indicated the presence of C=O, C-H, and O-H groups. These groups could indicate the presence of mushroom traces in the Ag NPs, which was confirmed via the amorphous characteristics of Ag NPs from the XRD analysis. The prepared Ag NPs have a high impact against different microorganisms, which could be attributed to the ability of Ag NPs to penetrate the cell bacterial wall.

Preparation, characterization and densification studies of W-Ag nanocomposites produced by chemical route

W-Ag has applications in a wide range of cutting-edge fields, counting heat sinks and microwave absorbers for micro—electronic components, electric arc ends, and filaments for welding processes, electrical contacts, and durable electronic connections. Chemical methods provide a number of benefits, including improved purity, and controlled particle size. The present study focused on the fabrication of W-Ag nano composites using chemical synthesis. W-Ag nanocomposites with average size less than 50 nm were synthesized using Tungsten hexacarbonyl (W(CO)6, and silver acetate (CH3-COOAg) as metal precursors in the present study. The W-Ag composites were sintered using conventional sintering. X-ray diffraction studies of as-prepared powders showed amorphous W-phase and FCC Ag, while sintered W-Ag composites exhibited crystalline BCC W and FCC Ag phase. The effect of sintering temperature on relative density and mechanical properties of W-Ag sintered compacts was investigated. Relative density in excess of 97.6%, 98.2% and 98.8% was achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composites on conventional sintering at 1000°C for 1 h. Vickers hardness of 364 ± 10 and 320 ± 8 Hv and 279 ± 6 were achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composite compacts respectively. The hardness value of W-Ag composites decreased with an increase in Ag content. The combination of properties realized in this study renders the composites suitable for automotive and heat sink applications.

Investigation on the microstructure, mechanical and electrical properties of Ti3SiC2/Cu joint obtained by Ti25Zr25Ni25Cu25 amorphous high entropy alloy and Ag composite filler

Ti3SiC2/Cu brazed joint has an important application in the pantograph of high-speed trains, but excessively continuous intermetallic compounds (IMC) and thick diffusion reaction zone (DRZ) in the joint are detrimental to both the mechanical and electrical properties of the joint. Therefore, regulating the interfacial microstructure is an effective way to acquire an excellent brazed joint. In this study, Ti25Zr25Ni25Cu25 amorphous high entropy alloy (HEA) was fabricated, and the brazing of Ti3SiC2 to Cu was carried out by the Ti25Zr25Ni25Cu25 HEA and Ag foil composite filler. The hysteresis effect of the HEA effectively slowed down the interfacial atomic diffusion and metallurgical reactions, which is conducive to the formation of relatively thin DRZ. Due to the combination of Ag foil and the HEA, the IMC distribution in the joint obtained at a relatively low temperature is more dispersed and uniform. Under the optimal brazing conditions, the maximum shear strength of the brazed joint obtained with the Ti25Zr25Ni25Cu25 and Ag composite filler is 34.85% higher than that obtained with Ag-26.7Cu-4.5Ti conventional filler. In particular, the electrical resistance of the joint obtained with the composite filler is 20.35% lower than that obtained with the single Ti25Zr25Ni25Cu25 HEA filler.

A facile and new preparation of crystalline Ag loaded TiO2 nanoparticles by a one-step method at room temperature

Crystalline Ag loaded TiO2 (c-Ag/TiO2) nanoparticles (NPs) has higher photocatalytic activity than amorphous Ag loaded TiO2 (a-Ag/TiO2) NPs, but its preparation usually requires multi steps and high temperatures. In this work, c-Ag/TiO2 NPs have been successfully prepared by one-step UV reduction at room temperature, using TiO2 (P25) and AgNO3 as raw materials. The phase, grain size, crystallinity and morphology of such c-Ag/TiO2 NPs have been analyzed by X-ray diffraction, element surface distribution and field emission transmission electron microscope. The crystal plane form of TiO2 is the main factor affecting the formation of c-Ag/TiO2 in the process of photoreduction of Ag+ to Ag0 on the surface of TiO2 at room temperature. Among the anatase and rutile phases of TiO2 (P25), rutile TiO2 (101) crystal plane is the predominant crystal plane for precipitation of crystalline Ag (111) to form c-Ag/TiO2.

Preparation of Ag–Fe2O3-Based black and electrically insulating coatings by magnetron sputtering from metal targets

Black and electrically insulating coatings provide touch panel displays with a classic appearance. In this study, black and electrically insulating Ag–Fe2O3-based coatings were prepared using reactive magnetron sputtering, stainless steel and silver foil. The thin films prepared with oxygen introduction and no Ag foil showed blue light absorption and high electrical resistance, which are comparable to those of Fe2O3 single crystals. The optimal Ag foil size for maintaining a high electrical resistivity of 108 Ω·sq−1 was determined to be 54 mol%Ag in the film samples. Black and electrically insulating thin films composed of metallic Ag, amorphous Ag–Fe–O, and slightly crystallized Fe2O3 were prepared using 3.4 or 3.9 %O2. Metallic Ag segregated randomly in the high-refractive-index Fe2O3-based matrix, resulting in plasmonic absorption over a wide range of wavelengths centered in the red-wavelength region. At 3.9 %O2, a high sheet resistance of 108 Ω·sq−1 and strong visible absorption of 35.2 μm−1 (on average), slightly deviating by 2.4 μm−1 were simultaneously achieved by clear phase separation of the Ag grains and Fe2O3-based matrix. A clear phase separation mechanism based on thermodynamic nonequilibrium oxidation of the metallic Ag phase is proposed.

Synthesis of TiO2/MoSx/Ag nanocomposites via photodeposition for enhanced photocatalysis and membrane fouling mitigation

In this research, to improve photocatalytic organic pollutant removal, we synthesized amorphous MoSx (a-MoSx) and Ag on TiO2 via a two-step photodeposition method. The As-synthesized TiO2/a-MoSx/Ag (TMA) photocatalyst exhibited a highly enhanced photocatalytic degradation performance of methylene blue which showed 3.6 times higher reaction rate constant than that of TiO2 photocatalyst. Furthermore, TMA photocatalyst was applied to the ultrafiltration (UF) membrane to mitigate fouling of the membrane. To realize a stable immobilization of photocatalyst on the membrane surface, polydopamine (PDA), which is a biocompatible mussel-inspired adhesive material, was utilized to form an adhesive layer. After PDA coating, TMA photocatalyst was stably deposited on the UF membrane, resulting to increased hydrophilicity. Fouling was successfully mitigated by photocatalytic self-cleaning property of TMA deposited UF membrane and flux recovery ratio was improved by 28% under irradiation. Owing to the simple and easy approach of both photodeposition-based heterostructure photocatalyst synthesis and post-processing of photocatalyst coating on the membrane, we present that our strategy for membrane fouling mitigation is suitable for future membrane technology.

Silver-functionalized silica aerogel for iodine capture: Adsorbent aging by NO2 in spent nuclear fuel reprocessing off-gas

Silver-functionalized silica aerogel (Ag 0 -Aerogel) is considered a promising porous adsorbent for the capture of iodine from nuclear fuel reprocessing off-gas. The Ag 0 -Aerogel, nevertheless, experiences a steady loss of capacity when exposed to NO 2 in the off-gas. This phenomenon is known as aging and its governing processes remain unclear. We exposed Ag 0 -Aerogel samples to 2% NO 2 in dry air at 150 °C for up to 1 month, followed by I 2 loading. Samples were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Our results elucidated the precise Ag species in Ag 0 -Aerogel that adsorb I 2 : (i) Ag 0 nanoparticles, (ii) Ag thiolates (Ag–S-r) covering the nanoparticles and the aerogel backbone, and (iii) Ag–S complexes including amorphous Ag 2 S. We unraveled the two predominant underlying processes of aging in NO 2 : (i) Ag–S-r is oxidized by NO 2 forming silver sulfonate (Ag–SO 3 -r) which is oxidized further to silver sulfate (Ag 2 SO 4 ) molecules, (ii) Ag 2 SO 4 molecules then migrate from the pores to the aerogel surface and aggregate yielding Ag 2 SO 4 particles that do not adsorb I 2 . Plausible reaction pathways and aggregation mechanisms are explored. These findings may be used to guide the discovery of more advanced materials for iodine capture and the development of accurate predictive models. • The iodine capacity of Ag-aerogel is reduced by NO 2 at elevated temperatures. • Ag nanoparticles and Ag–S compounds coherently adsorb iodine. • NO 2 oxidizes Ag-thiolates forming Ag 2 SO 4 molecules that favor iodine adsorption. • Ag 2 SO 4 molecules migrate and accumulate on particles preventing iodine adsorption. • Thiolation step directly impacts Ag-aerogel aging in NO 2 .

Изменение состояния поверхности монокристаллического германия в результате имплантации ионами серебра и отжига световыми импульсами

Single-crystal c-Ge plates implanted with Ag+ ions with an energy of E=30 keV, current density of the ion beam J = 5 μA/cm2 and a dose of D=2.5×1016 ion/cm2 were subjected to rapid thermal annealing by single light pulses of various durations from 1 up to 9.5 s. By scanning electron microscopy and optical reflection spectroscopy measurements it was shown that after ion implantation an amorphous porous Ag:PGe layer of spongy structure, consisting of Ge nanowires, is formed on the surface of c-Ge substrates. It was found that the annealing with an increase in the pulse duration up to 5 s successively leads to an increase in the Ge nanowire diameters from 26 to 35 nm. With longer pulses, the porous Ag:PGe structure is destroyed and Ag evaporates from the implanted layers.

Change in the surface state of the single-crystal germanium as a result of implantation with silver ions and annealing with light pulses

Single-crystal c-Ge plates implanted with Ag+ ions with an energy of E=30 keV, current density of the ion beam J = 5 μA/cm2 and a dose of D = 2.5· 1016 ion/cm2 were subjected to rapid thermal annealing by single light pulses of various durations from 1 up to 9.5 s. By scanning electron microscopy and optical reflection spectroscopy measurements it was shown that after ion implantation an amorphous porous Ag : PGe layer of spongy structure, consisting of Ge nanowires, is formed on the surface of c-Ge substrates. It was found that the annealing with an increase in the pulse duration up to 5 s successively leads to an increase in the Ge nanowire diameters from 26 to 35 nm. With longer pulses, the porous Ag : PGe structure is destroyed and Ag evaporates from the implanted layers. Keywords: nanoporous germanium, ion implantation, rapid thermal annealing.

Formation of nanoporous Ge layers by ion implantation at different temperatures of c-Ge substrate

The flat monocrystalline c-Ge wafers implanted by 108Ag + ions with the energy E = 30 keV, dose D = 1.3·1016 ion/cm2 and at current density J = 5 μA/cm2 for various substrate temperatures from 25 to 400 °C were studied. By scanning electron microscopy and optical reflection spectroscopy it was found that as a result of ion implantation in the temperature range from 25 to 300 °C an amorphous porous Ag:PGe layers of a spongy structure consisting of Ge nanowires on the c-Ge substrate surface are formed. The diameter of Ge nanowires increases from 16 to 24 nm with a rising of substrate temperature. It is shown that at the highest temperature of 400 °C, the porous structure does not form and the Ge surface remains flat on which the formation of Ag nanoparticles can be observed. A change in the level of the sample surface in dependence on substrate temperature due to swelling up to 280 °C was replaced by effective ion sputtering at higher temperatures.

Metallic Ag Confined on SnO2 Surface for Soot Combustion: the Influence of Ag Distribution and Dispersion on the Reactivity

AbstractTo unravel the surface confinement effect of SnO2 for Ag, and find an effective way to design practical soot combustion catalysts, an XRD extrapolation method has been adopted for the first time to analyze the distribution and dispersion of metallic Ag on SnO2 surface. Ag addition can generate more surface oxygen vacancies on SnO2, thus forming richer amount of surface O2− and O22− anions. However, the amount of soot reactive oxygen sites is significantly influenced by the distribution of Ag. It is quantified that 1.86 mmol Ag/100 m2 SnO2 surface, which is equal to 5.2 wt% loading, is a threshold value for Ag distribution. Below the threshold, Ag is nearly in amorphous state, and has strong interaction with the SnO2 support, thus producing more soot reactive surface oxygen sites. Furthermore, the redox property of SnO2 lattice oxygen is enhanced by Ag addition. Therefore, metallic Ag in nearly amorphous state plays a critical role for the reaction. Ag crystallites formed on the surface above the threshold have negative influence on the activity. The best Ag/SnO2 catalyst can be fabricated by loading the threshold amount of Ag over SnO2 surface to get the maximum quantity of amorphous Ag species.

Incoherent-light pulse annealing of nanoporous germanium layers formed by ion implantation

The study addresses the monocrystalline c-Ge substrates implanted by Ag+ ions with the energy of 30 keV, irradiation dose of 7.5·1016 ion/cm2 at current density of 8 μA/cm2 and annealed by incoherent-light pulse. By scanning electron microscopy and optical reflection spectroscopy measurements it was shown that after ion implantation an amorphous porous Ag:PGe layer of a spongy structure with nanowires on the c-Ge substrate were formed. Pulsed light annealing of the implanted samples leads to partial melting and recrystallization of the surface Ag:PGe layer. The spongy annealed structure of the Ag:PGe layer was not destroyed, however the diameters of nanowires increased by about 1,5 times.

Multi-particle molecular dynamics simulation: shell thickness effects on sintering process of Cu-Ag core-shell nanoparticles

As a substitute for pure silver nanoparticles, Cu-Ag core-shell nanoparticles (CS NPs) have received significant attention in the fields of electronic packaging and conductive inks. Shell thickness is one of the important factors affecting the sintering performance of CS NPs. In this work, we conduct a multi-particle molecular dynamics simulation to investigate the shell thickness effects on the sintering process of Cu-Ag CS NPs at different temperatures. The results show that the less the shell thickness, the lower the potential energy decrease during sintering. This study mainly involves two sintering mechanisms, plastic deformation mechanism, and diffusion mechanism. During the sintering process, the contribution of the plastic deformation mechanism decrease with the layer thickness decreases. As for the diffusion mechanism, the self-diffusion coefficient at 500 K is much lower than that at higher temperatures. However, the slow diffusion can increase the densification by filling the pores generated in the initial stage of sintering. The self-diffusion coefficient of surface atoms increases as the shell thickness decreases. The decrease of shell thickness can produce more lattice mismatches at the core-shell interface, which hinders crystallization during the sintering process. And we found more amorphous Ag atoms at the sintering neck. A higher sintering temperature can induce the diffusion of Cu atom near the core-shell interface, especially for the particle with thinner shell thickness. Some diffused Cu atoms were found in the neck area of sintered CS NP of Ag5Cu3.5 and Ag5Cu4 at 700 K. Moreover, the sintered neck partly composed of Cu atoms was observed in sintered Ag5Cu4 CS NPs at 900 K.

Characterization of the iron oxide phases formed during the synthesis of core–shell FexOy@C nanoparticles modified with Ag

Core–shell FexOy@C nanoparticles (NPs) modified with Ag were studied with x-ray diffraction, transmission electron microscopy, energy dispersive elemental mapping, Mössbauer spectroscopy, static magnetic measurements, and optical magnetic circular dichroism (MCD). FexOy@C NPs synthesized by the pyrolysis process of the mixture of Fe(NO3)3 · 9H2O with oleylamine and oleic acid were added to a heated mixture of oleylamine and AgNO3 in different concentrations. The final product was a mixture of iron oxide crystalline NPs in an amorphous carbon shell and Ag crystalline NPs. The iron oxide NPs were presented by two magnetic phases with extremely close crystal structures: Fe3O4 and γ-Fe2O3. Ag is shown to form crystalline NPs located very close to the iron oxide NPs. An assumption is made about the formation of hybrid FexOy@C-Ag NPs. Correlations were obtained between the Ag concentration in the fabricated samples, their magnetic properties and the MCD spectrum shape. Introducing Ag led to a approximately linear decrease of the NPs saturation magnetization depending upon the Ag concentration, it also resulted into the MCD spectrum shift to the lower light wave energies. MCD was also studied for the Fe3O4@C NPs synthesized earlier with the same one-step process using different heat treatment temperatures, and MCD spectra were compared for two series of NPs. A possible contribution of the surface plasmon excitation in Ag NPs to the MCD spectrum of the FexOy@C-Ag NPs is discussed.

Thermally-evaporated C60/Ag/C60 multilayer electrodes for semi-transparent perovskite photovoltaics and thin film heaters

ABSTRACT We investigated the characteristics of thermally evaporated fullerene (C60)/Ag/C60 (CAC) multilayer films for use in semi-transparent perovskite solar cells (PSCs) and thin-film heaters (TFHs). The top and bottom C60 layers and Ag interlayer were prepared using multi-source thermal evaporation, and the thickness of the Ag interlayer was investigated in detail for its effects on the resistivity, optical transmittance, and mechanical properties of the CAC electrodes. We used a figure-of-merit analysis to obtain a CAC electrode with a smooth surface morphology that exhibited a sheet resistance of 5.63 Ohm/square and an optical transmittance of 66.13% at a 550 nm wavelength. We conducted mechanical deformation tests to confirm that the thermally evaporated multilayer CAC electrode has a high durability, even after 10,000 times of inner and outer bending, rolling, and twisting due to the flexibility of the amorphous C60 and Ag interlayer. We evaluated the feasibility of using CAC electrodes for semi-transparent PSCs and TFHs. The semi-transparent PSC with 1.08 cm2 active area prepared with a transparent multilayer CAC cathode showed a power conversion efficiency (PCE) of 5.1%. Furthermore, flexible TFHs (2.5 × 2.5 cm2) fabricated on a thermally evaporated CAC electrode show a high saturation temperature of 116.6 C, even at a low input voltage of 4.5 V, due to a very low sheet resistance. Based on the performance of the PSCs and TFHs, we conclude that the thermally evaporated multilayer CAC electrode is promising for use as a transparent conductive electrode (TCE) for semi-transparent PSCs and TFHs, with characteristics comparable to sputtered TCEs.

Synthesis of Ag–Carbon–TiO2 composite tubes and their antibacterial and organic degradation properties

Ag–Carbon–TiO2 composite tubes were prepared by using polystyrene/AgNO3 composite fibers as a sacrifice template and a co-pyrolysis process. The Ag–Carbon–TiO2 tubes were characterized by SEM, TEM, X-ray diffraction, Raman spectrum, XPS, and UV–vis spectrum. The results showed that the Ag–Carbon–TiO2 tubes possessed uniform tubular structure with amorphous carbon, graphitic carbon, and Ag nanoparticles (AgNPs) distributing uniformly in TiO2. The Ag–Carbon–TiO2 tubes were confirmed high UV–vis light utilization and photocatalytic degradation efficiency to Rhodamine B due to the carbon doping, the surface plasmon resonance of AgNPs and the tubular structure, and the degradation of Rhodamine B reached 90% in 6 h. Meanwhile, they showed an excellent antibacterial effect on staphylococcus aureus, and the fatality rate of Ag–Carbon–TiO2 tubes to staphylococcus aureus reached 99.9% in 24 h when its concentration was higher than 4 mg/ml. The co-pyrolysis process could repress the AgNPs to grow to be large particles, which could be a key for the excellent antibacterial property. The research showed a promising strategy for preparing Ag–Carbon–TiO2 composite tubes by co-pyrolysis of PS composite electrospinning fibers, indicating their potential application in wastewater treatment and antibacterial materials.

Effects of Ag coating on the structural and electrochemical properties of LiNi0.8Co0.1Mn0.1O2 as cathode material for lithium ion batteries

Ni-rich layered oxide LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode materials are synthesized using Ni0.8Co0.1Mn0.1(OH)2 precursors obtained from a co-precipitation reaction and then coated with of metal Ag for the first time. X-ray diffraction results verify that Ag+ ions can hardly dope into the bulk NCM811 particles and the ion mixing degree of Li+/Ni2+ has been reduced. Amorphous Ag coating layers formed on the surface of Ag coated NCM811 materials are proved by scanning electron microscope and transmission electron microscope. X-ray photoelectron spectroscopy demonstrates that more Ni3+ ions on the surface of Ag coated NCM811 materials than that of pure NCM811. Galvanostatic charge-discharge tests indicate that 1 wt% Ag coated NCM811 exhibits initial discharge capacity of 209.1 mAh·g−1 and superior capacity retention of 90.5% after 90 cycles between 2.8 and 4.3 V, which shows greatly improved cycling stability compared with the pure NCM811 (87.9%). After Ag coating, reduced electrode polarization is certified by cyclic voltammetry, and better electron conductivity and higher Li+ diffusion coefficient are testified by electrochemical impedance spectroscopy. These results clearly indicate Ag coating can enhance the structural and electrochemical properties of NCM811 materials.