In Situ Growth of 2D Metal–Organic Framework Ion Sieve Interphase for Reversible Zinc Anodes

Zinc metal anodes are gaining popularity in aqueous electrochemical energy storage systems for their high safety,cost-effectiveness,and high capacity.However,the service life of zinc metal anodes is severely constrained by critical challenges,including dendrites,water-induced hydrogen evolution,and passivation.In this study,a protective two-dimensional metal–organic framework interphase is in situ constructed on the zinc anode surface with a novel gel vapor deposition method.The ultrathin interphase layer(~1μm)is made of layer-stacking 2D nanosheets with angstrom-level pores of around 2.1Å,which serves as an ion sieve to reject large solvent–ion pairs while homogenizes the transport of partially desolvated zinc ions,contributing to a uniform and highly reversible zinc deposition.With the shielding of the interphase layer,an ultra-stable zinc plating/stripping is achieved in symmetric cells with cycling over 1000 h at 0.5 mA cm−2 and~700 h at 1 mA cm^(−2),far exceeding that of the bare zinc anodes(250 and 70 h).Furthermore,as a proof-of-concept demonstration,the full cell paired with MnO_(2) cathode demonstrates improved rate performances and stable cycling(1200 cycles at 1 A g−1).This work provides fresh insights into interphase design to promote the performance of zinc metal anodes.

Development of Superhydrophobic Nano-SiO_(2)and Its Field Application in Low-permeability,High-temperature,and High-salinity Oil Reservoirs

In this study,to meet the stringent requirements on the hydrophobicity of nano-SiO_(2)particles for use in depressurization and enhanced injection operations in high-temperature and high-salinity oil reservoirs,secondary chemical grafting modification of nano-SiO_(2)is performed using a silane coupling agent to prepare superhydrophobic nano-SiO_(2) particles.Using these superhydrophobic nano-SiO_(2)particles as the core agent,and liquid paraffin or diesel as the dispersion medium,a uniform dispersion of nano-SiO_(2)particles is achieved under high-speed stirring,and a chemically enhanced water injection system with colloidal stability that can be maintained for more than 60 d is successfully developed.Using this system,a field test of depressurization and enhanced injection is carried out on six wells in an oilfield,and the daily oil production level is increased by 11 t.The cumulative increased water injection is 58784 m^(3),the effective rate of the measures was 100%,and the average validity period is 661 d.

Activation mechanism of conventional electrolytes with amine solvents:Species evolution and hydride-containing interphase formation

Rechargeable magnesium(Mg)-metal batteries have brought great expect to overcome the safety and energy density concerns of typical lithium-ion batteries.However,interracial passivation of the Mgmetal anode impairs the reversible Mg plating/stripping chemistries,resulting in low Coulombic efficiency and large overpotential.In this work,a facile isobutylamine(IBA)-assisted activation strategy has been proposed and the fundamental mechanism has been unveiled in a specific way of evolving active species and forming MgH_(2)-based solid-electrolyte interphase.After introducing IBA into a typical electrolyte of magnesium bis(trifluoromethanesulfo nyl) imide(Mg(TFSI)_(2)) in diglyme(G2) solvents,electrolyte species of [Mg^(2+)(IBA)5]^(2+) and protonated amine-based cations of [(IBA)H]^(+) have been detected by nuclear magnetic resonance and mass spectra.This not only indicates direct solvation of IBA toward Mg^(2+)but also suggests its ionization,which is central to mitigating the decomposition of G2 and TFSI anions by forming neutrally charged [(IBAH^(+))(TFSI^(-))]~0 and other complex ions.A series of experiments,including cryogenic-electron microscopy,D_(2)O titration-mass spectra,and time of flight secondary ion mass spectrometry results,reveal a thin,non-passivated,and MgH_(2)-containing interphase on the Mg-metal anode.Besides,uniform and dendrite-free Mg electrodeposits have been revealed in composite electrolytes.Benefiting from the activation effects of IBA,the composite electrolyte displays superior electrochemical performance(overpotential is approximately 0.16 V versus 2.00 V for conventional electrolyte;Coulombic efficiency is above 90% versus <10% for conventional electrolyte).This work offers a fresh direction to advanced electrolyte design for next-generation rechargeable batteries.

Nano-SiO_(2)和镍渣掺量对碱矿渣砂浆强度和自收缩的影响

为改善碱矿渣砂浆自收缩大的缺陷,将Nano-SiO_(2)和镍渣掺入其中,研究两者掺量对抗折强度、抗压强度和自收缩的影响。研究结果表明:在镍渣掺量一定时,随着Nano-SiO_(2)掺量的增加强度值先提高后降低,掺量为1%时强度值最高,对强度的提高幅度也最大;当Nano-SiO_(2)掺量一定时,随着镍渣掺量的增加强度值逐渐降低,掺量为30%时强度降低幅度最小;当镍渣掺量为30%,随着Nano-SiO_(2)掺量的增加,自收缩值先降低后提高,掺量为1%时,自收缩值最小,对自收缩的降低幅度也最大;当Nano-SiO_(2)掺量为1%时,随着镍渣掺量的增加自收缩值逐渐降低,掺量为30%时降低幅度最大。

Work-function effect of Ti_(3)C_(2)/Fe-N-C inducing solid electrolyte interphase evolution for ultra-stable sodium storage

In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge efficiency and the overall longevity of the battery.Herein,a novel two-dimensional Ti_(3)C_(2) fragments enmeshed on iron-nitrogen-carbon(Fe-N-C)nanosheets(Ti_(3)C_(2)/Fe-NC)has been synthesized.This electrode features a matrix which has been shown to expedite SEI layer formation through the facilitation of selective anion adsorption,thus augmenting battery performance.Density functional theory calculation reveals that the SEI evolution energy of NaPF6 at the Ti_(3)C_(2)/Fe-N-C interface is 0.81 eV,significantly lower than the Ti_(3)C_(2)(1.23 eV).This process is driven by the electron transportation from Ti_(3)C_(2) to Fe-N-C substrate,facilitated by their work-function difference,leading to the formation of ferromagnetic Fe species,which possesses Fe 3d d_(xz)d_(z)2 orbitals and undergoes hybridization with theπandσorbitals of NaF,creating a key intermediate during charging.This process diminishes the antibonding energy and attenuates the orbital interaction with NaF,thus reducing the activation energy and improving the SEI formation reaction kinetics.Consequently,it leads to the creation of multi-interface SEI characterized by high-throughput ion transport and an efficient reaction network.

Research on a New Process of Preparation for Nano-SiO_2 with High Activity and Mesopores

Nano-SiO_2 with high activity and mesopores was prepared through sol-gel synthesis followed by low-temperatureheat treatment and ball milling firstly in our experiments. TEM was performed to measure particle sizes. Nitrogenadsorption experiments were carried out to estimate specific surface area, porous distribution and porous ratio by BETand BJH methods. The content of Si-OH in SiO_2 surface was calculated by analysis of the results of hydrogen-oxygencontent mensuration (HOCM). As a result, appropriate heat treatment system and ball milling time are important topreparation for nano-SiO_2 with high activity and mesopores, which are 5～50 nm particles, 5～6 nm average aperture,85%～93% porous ratio, and 51%～55% Si-OH content in surface. Nano-SiO_2 with that structure has high surfaceenergy and activity. This process, which has simple facilities and operation rules, is a new way of preparation fornano-SiO_2 with high activity and mesopores.

Protective electrode/electrolyte interphases for high energy lithium-ion batteries with p-toluenesulfonyl fluoride electrolyte additive

High energy density lithium-ion batteries using Ni-rich cathode(such as LiNi0.6Co0.2Mn0.2O2) suffer from severe capacity decay.P-toluenesulfonyl fluoride(pTSF) has been investigated as a novel film-forming electrolyte additive to enhance the cycling performances of graphite/LiNi0.6Co0.2Mn0.2O2 pouch cell.In comparison with the baseline electrolyte,a small dose of pTSF can significantly improve the cyclic stability of the cell.Theoretical calculations together with experimental results indicate that pTSF would be oxidized and reduced to construct protective interphase film on the surfaces of LiNi0.6Co0.2Mn0.2O2 cathode and graphite anode,respectively.These S-containing surface films derived from pTSF effectively mitigate the decomposition of electrolyte,reduce the interphasial impedance,as well as prevent the dissolution of transition metal ions from Ni-rich cathode upon cycling at high voltage.This finding is beneficial for the practical application of high energy density graphite/LiNi0.6Co0.2Mn0.2O2 cells.

Tailoring interphase structure to enable high-rate, durable sodium-ion battery cathode

Na-based layered transition metal oxides with O_(3)-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the Otype Na-coordinate environment compromises their rate and cycle capability, hindering their practical application. Here, we report an interphase-structure tailoring strategy that improves the electrochemical properties of O_(3)-type layered cathodes achieved through surface coating and doping processes.Specifically, a Zr-doped interphase structure is designed in the model compound NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2) using the ionic conductor Na_(3)Zr_(2)Si_(2)PO_(12) as the surface coating material and Zr-dopant provider. We discover that the modified NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)cathode shows a stable Na-storage structure as well as an enhanced rate/cycle capability. Combined with theoretical calculations, it is suggested that the superior electrochemical performances originate from the Zr-doped interphase structure, which has an enlarged Na layer spacing that forms favorable Na-ion diffusion channels. This work highlights a general material interface optimization method which opens a new perspective for fabricating high-performance electrodes for Na-ion batteries and beyond.

Ultraviolet shielding property of crylic acid resin filled with nano-SiO_2

The present status and development trends of nano-composite coatings were briefly introduced. The nano-SiO2 was dispersed into crylic acid resin by ultrasonic wave and high-energy ball milling, the influence of nano-SiO2 on shielding property of coatings was investigated. Relation between particle size distribution of original nano-SiO2 and its dispersal in water and alcohol after treatment were analyzed, respectively. The ultraviolet permeation rate of coatings filled with nano-SiO2 was detected by ultraviolet spectral photometer. And the particle size distribution of coatings was examined by TEM. The results show that particle size distribution is comparative convergence and smaller one order of magnitude after dispersal treatment. The size of most nano-SiO2 in coatings is smaller than 100nm, which indicates that the amount of nano-SiO2 in the resin is 20% （solid content of resin）, the permeation rate of ultraviolet of composite coatings decreases to 20%. The research of its excellent ultraviolet shielding property mechanism indicates minor size and high surface energy of nano-SiO2 can produce different absorption, reflection and scatter actions to different wavelengths.

Mechanical Properties and Fire Retardancy of Wood Flour/High-Density Polyethylene Composites Reinforced with Continuous Honeycomb-Like Nano-SiO_(2)Network and Fire Retardant

The mechanical properties of wood flour/high-density polyethylene composites(WPC)were improved by adding a small amount of nano-SiO_(2)to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO_(2)network.The wood flour was modified with a fire retardant(a mixture of sodium octabonate and amidine urea phosphate)to improve its fire retardancy.The flexural properties,creep resistance,thermal expansion,and fire retardancy of the WPC were compared to a control(WPCCTRL)without nano-SiO_(2)or fire retardant.The flexural strength and modulus of the WPC containing only 0.55 wt.%nano-SiO_(2)were 6.6%and 9.1%higher than the control,respectively,while the creep strain and thermal expansion rate at 90°C were 33.8%and 13.6%lower,respectively.The cone calorimetry tests revealed that the nano-SiO_(2)network physically shielded the WPC,giving it lower heat release and smoke production rates.The thermal expansion was further decreased by incorporating fire retardants into the WPC,which showed the lowest total heat release and total smoke production and the highest mass retention.This study demonstrates a facile procedure for producing WPC with desired performances by forming a continuous honeycomb-like network by adding a small amount of nanoparticles.

Synthesis and Characterization of Modified Epoxy Resins by Silicic Acid Tetraethyl Ester and Nano-SiO_2

A kind of modified epoxy resins was obtained by condensation of epoxy resin with silicic acid tetraethyl ester（TEOS） and nano-SiO2. The reactions were performed with hydrochloric acid as a catalyst at 63 ℃. The structure, thermal stability and morphological characteristics of the modified epoxy resins were studied through infrared spectra（FT-IR） analysis, thermogravimetric（TG） analysis and scanning electron microscopy respectively. It has been found from the IR and TG study that modified epoxy resins have greater thermal stability than epoxy resins, and its thermal stability has been improved by the formation of inter-crosslinked network structure. The modified epoxy resins exhibit heterogeneous morphology and heterogeneity increases with more TEOS feeding, which in turn confirms the formation of inter-crosslinked network structure in modified epoxy resins.

A robust interphase via in-situ pre-reconfiguring lithium anode surface for long-term lithium-oxygen batteries

Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.

Effect of nano TiO_(2) and SiO_(2) on gelation performance of HPAM/PEI gels for high-temperature reservoir conformance improvement

Nanoparticles have been widely used in polymer gel systems in recent years to improve gelation performance under high-temperature reservoir conditions. However, different types of nanoparticles have different effects on their gelation performance, which has been little researched. In this study, the high-temperature gelation performance, chemical structure, and microstructure of polymer gels prepared from two nanomaterials (i.e., nano-SiO_(2) and nano-TiO_(2)) were measured. The conventional HPAM/PEI polymer gel system was employed as the control sample. Results showed that the addition of nano-TiO_(2) could significantly enhance the gel strength of HPAM/PEI gel at 80 ℃. The gel strength of the enhanced HPAM/PEI gel with 0.1 wt% nano-TiO_(2) could reach grade I. The system also had excellent high-temperature stability at 150 ℃. The enhanced HPAM/PEI gel with 0.02 wt% nano-TiO_(2) reached the maximum gel strength at 150 ℃ with a storage modulus (G′) of 15 Pa, which can meet the need for efficient plugging. However, the nano-SiO_(2) enhanced HPAM/PEI polymer gel system showed weaker gel strength than that with nano-TiO_(2) at both 80 and 150 ℃ with G′ lower than 5 Pa. Microstructures showed that the nano-TiO_(2) enhanced HPAM/PEI gel had denser three-dimensional (3D) mesh structures, which makes the nano-TiO_(2) enhanced HPAM/PEI gel more firmly bound to water. The FT-IR results also confirmed that the chemical structure of the nano-TiO_(2) enhanced HPAM/PEI gel was more thermally stable than nano-SiO_(2) since there was a large amount of –OH groups on the structure surface. Therefore, nano-TiO_(2) was more suitable as the reinforcing material for HPAM/PEI gels for high-temperature petroleum reservoir conformance improvement.

右美托咪定对老年2型糖尿病患者全麻气管插管期心血管反应的影响

目的探讨静脉注射盐酸右美托咪定对老年2型糖尿病患者全身麻醉(全麻)气管插管期心血管反应的影响。方法 82例择期行中上腹部手术的老年2型糖尿病患者,随机分成D组和C组,各41例。D组行盐酸右美托咪定静脉注射麻醉诱导,C组行等容量氯化钠(NaCl)溶液静脉注射空白对照,记录并比较麻醉前后不同时刻的QTc间期、血压及心率(HR)变化。结果麻醉诱导后1 min(T_1)、3 min(T_2),两组收缩压(SBP)、舒张压(DBP)较麻醉诱导前(T_0)稍降低,且D组SBP和DBP降低幅度大于C组,差异有统计学意义(P<0.05);插管后30 s(T_3)、3 min(T_4),两组HR、SBP和DBP较T0均显著升高,且D组HR、SBP及DBP小于C组,差异有统计学意义(P<0.05),D组QTc间期与T0比较差异无统计学意义(P>0.05),C组延长且明显长于D组,差异有统计学意义(P<0.05)。气管插管后C组QTc间期延长并>440 ms者11例(26.8%),明显多于D组的2例(4.9%),差异有统计学意义(P<0.05)。结论静脉注射右美托咪定能明显抑制老年2型糖尿病患者因全麻诱导围气管插管期导致的QTc间期延长,能一定程度抑制插管引起的心血管应激反应,维持血流动力学平稳。

Synthesis of a High-Efficiency Demulsifier and Study on Optimal Demulsification Conditions

Oil and water separation has always been a top priority in the oil industry.In this study,a series of hyperbranched fluorinated polyamine-amine polymers(HFPA1-5)were synthesized directly using an improved“one-pot method.”The highly active fluorinated p-trifluoromethylaniline was used as the core raw material,while diethylenetriamine and methyl acrylate were used as the chain segment.A hyperbranched fluorine-containing polyamine-amine demulsifier(NHFPA6)was obtained through nano-grafting copolymerization of HFPA5.To enhance the demulsification and dehydration performance,the copolymerized HFPA6 was modified and combined.Then,the effects of the combination ratio,demulsifier concentration,demulsification time,and demulsification temperature on the demulsification effect were investigated.The results revealed that a combination ratio of DE-401:NHFPA6=1:1,a demulsification temperature of 50℃,a demulsification time of 60 min,and a demulsifier concentration of 150 mg/L yielded a dehydration rate as high as 99.80%.A response surface optimization design of demulsification conditions was performed.The model verified that the optimal demulsification conditions were 50℃,300 mg/L,and 90 min.However,considering the economic benefits of factories,it is more favorable to select demulsification conditions with a shorter time and lower concentration when the dehydration standard is met.Therefore,the demulsification conditions were selected as 50℃,150 mg/L,and 60 min.Compared to existing demulsifiers,the demulsifier developed in this study exhibits a lower demulsification temperature and higher demulsification efficiency.

Tailored ZnF_(2)/ZnS-rich interphase for reversible aqueous Zn batteries

The urgent need for highly safe and sustainable large-scale energy storage systems for residential buildings has led to research into aqueous zinc ion batteries.However,when zinc is used in aqueous zinc ion batteries,it suffers from severe irreversibility due to its low Coulombic efficiency,dendrite growth,and side reactions.To address these challenges,we take advantage of organic cation to induce trifluoromethanesulfonate decomposition to build zinc fluoride/zinc sulfide-rich solid electrolyte interphase(SEI)that not only can adapt to a high areal capacity of deposition/stripping disturbance but also adjust zinc ion deposition path to eliminate dendrite.As a result,the unique interface can promote the Zn battery to achieve excellent electrochemical performance:high levels of plating/stripping Coulombic efficiency(99.8%),stability life(6,600 h),and cumulative capacity(66,000 mAh·cm^(−2))at 68%zinc utilization(20 mAh·cm^(−2)).More importantly,the SEI significantly enhances the cyclability of full battery under limited Zn,lean electrolyte,and high areal capacity cathode conditions.

Preparation and Properties of Heat Resistant Polylactic Acid(PLA)/Nano-SiO2 Composite Filament

In order to improve the thermal properties of polylactic acid（PLA） filament,nano-SiO_2 was applied to mix with PLA,then they were spun as composite filament by melt-spinning.The dispersion of nano SiO_2 and the fracture surfaces of filaments were studied by scanning electron microscopy（SEM）.The properties of composite filament,such as orientation degree,mechanical properties,and surface friction properties,were analyzed.The thermal performances of composite filament were analyzed by differential scanning calorimetry（DSC） and thermo gravimetric analysis（TGA）.The results showed that the nano-SiO_2 modified by 5% KH-550 could disperse evenly and loosely in nano-scale,and 1 wt% and 3 wt% nano-SiO_2 dispersed throughout PLA evenly.As the quantity of nano-SiO_2 increased,the properties of composite filament,such as orientation degree,friction coefficient,thermal decomposition temperature,and glass transition temperature,increased more or less.The breaking tenacity increased when 1 wt% SiO_2 was added in PLA,but declined when 3 wt% SiO_2 was added.

Electron energy levels determining cathode electrolyte interphase formation

Cathode electrolyte interphase(CEI)has a significant impact on the performance of rechargeable batteries and is gaining increasing attention.Understanding the fundamental and detailed CEI formation mechanism is of critical importance for battery chemistry.Herein,a diverse of characterization tools are utilized to comprehensively analyze the composition of the CEI layer as well as its formation mechanism by LiCoO_(2)(LCO)cathode.We reveal that CEI is mainly composed of the reduction products of electrolyte and it only parasitizes the degraded LCO surface which has transformed into a disordered spinel structure due to oxygen loss and lithium depletion.Based on the energy diagram and the chemical potential analysis,the CEI formation process has been well explained,and the proposed CEI formation mechanism is further experimentally validated.This work highlights that the CEI formation process is nearly identical to that of the anode-electrolyte-interphase,both of which are generated due to the electrolyte directly in contact with the low chemical potential electrode material.This work can deepen and refresh our understanding of CEI.

Y_5Si_3C and Y_3Si_2C_2: Theoretically predicted MAX phase like damage tolerant ceramics and promising interphase materials for SiC_f/SiC composites

Researching for interphase materials that can protect SiC fibers from oxygen and water vapor attacks has become one of the most important issues for the applications of SiC_f/SiC composites in high-temperature combustion environment. However, such kinds of interphase materials are not available yet. Herein,we report theoretically predicted properties of two promising interphase materials Y_5Si_3 C and Y_3Si_2C_2.Although crystallizing in different structures, they share the common features of layered structure,anisotropic chemical bonding, anisotropic electrical and mechanical properties, and low shear deformation resistance. The bulk moduli for Y_5Si_3C and Y_3Si_2C_2 are 78 and 93 GPa, respectively; while their shear moduli are 52 and 50GPa, respectively. The maximum to minimum Young's modulus ratios are1.44 for Y_5Si_3C and 3.27 for Y_3Si_2C_2. Based on the low shear deformation resistance and low Pugh's ratios(G/B = 0.666 forY_5Si_3C and 0.537 for Y_3Si_2C_2; G: shear modulus; B: bulk modulus), they are predicted as damage tolerant and soft ceramics with predicted Vickers hardness of 9.6 and 6.9 GPa, respectively.The cleavage plane and possible slip systems are(000 l) and(0001)[1120] and(1010)[0001] forY_5Si_3C,and those for Y_3Si_2C_2 are {h00} and(010)[101]. Since the oxidation products are water-vapor resistant Y2 Si2 O7, Y2 SiO5 and/or Y_2 O_3 upon oxidation, and the volume expansions are ca 140% and ca 26% for Y_5Si_3C and Y_3Si_2C_2, they are expected to seal the interfacial cracks in SiC_f/SiC composites. The unique combination of easy cleavage, low shear deformation resistance, volume expansions upon oxidation, and the resistance of the oxidation products to water vapor attack warrant them promising as interphase materials of SiC_f/SiC composites for water-vapor laden environment applications.

Role of nanoparticles in achieving macroscale superlubricity of graphene/nano-SiO_(2) particle composites

Recent studies have reported that adding nanoparticles to graphene enables macroscale superlubricity to be achieved.This study focuses on the role of nanoparticles in achieving superlubricity.First,because graphene nanoscrolls can be formed with nanoparticles as seeds under shear force,the applied load(or shear force)is adjusted to manipulate the formation of graphene nanoscrolls and to reveal the relationship between graphene-nanoscroll formation and superlubricating performance.Second,the load-carrying role of spherical nano-SiO_(2)particles during the friction process is verified by comparison with an elaborately designed fullerene that possesses a hollow-structured graphene nanoscroll.Results indicate that the incorporated nano-SiO_(2)particles have two roles in promoting the formation of graphene nanoscrolls and exhibiting load-carrying capacity to support macroscale forces for achieving macroscale superlubricity.Finally,macroscale superlubricity(friction coefficient:0.006–0.008)can be achieved under a properly tuned applied load(2.0 N)using a simple material system in which a graphene/nano-SiO_(2)particle composite coating slides against a steel counterpart ball without a decorated diamond-like carbon film.The approach described in this study could be of significance in engineering.