Dielectric Barrier Discharge Plasma Research Articles

Effect of O2/n-C5H12 Ratio on Oxygenates Production from Plasma N-pentane Partial Oxidation

Objective: Non-thermal plasma is a promising method for producing clean fuels. This work provides a deeper understanding of the impact of O2/n-C5H12 ratio on the partial oxidation of n-pentane from both physical and chemical perspectives. Moreover, this work offers insight into improving fuel combustion efficiency and technical support for the preparation of clean fuels. Methods: An experimental system based on dielectric barrier discharge plasma was established. The discharge characteristics and product generation status of n-pentane partial oxidation were measured by changing the concentration of oxygen and n-pentane to evaluate different O2/n-C5H12 ratios. Results: Research on discharge characteristics showed that the O2/n-C5H12 ratio did not affect the discharge mode, and typical Lissajous shapes were present at different ratios. Changing the O2/n-C5H12 ratio affected the oxygen concentration, average electron energy or electron density, and background temperature. As the O2/n-C5H12 ratio increased, the conversion of the n-pentane partial oxidation reaction increased. However, changing the O2/n-C5H12 ratio did not affect the type of generated products. The oxygenates exhibited a volcano curve, and an O2/n-C5H12 ratio of 1.00 achieved the highest selectivity of 35.1%. As the O2/n-C5H12 ratio continued to increase, the selectivity of oxygenates decreased and the selectivity of CO2 increased. This was potentially due to a shift from partial oxidation toward complete oxidation, which led to the generation of secondary pollutants. Thus, higher O2/n-C5H12 ratios were not conducive to clean fuel production and environmental friendliness. Conclusion: In the partial oxidation of n-pentane, the highest clean fuel production rate was achieved when the O2/n-C5H12 ratio was 1.00. When this ratio exceeded 1.00, the reaction shifted toward complete oxidation, producing secondary pollutants. This study provides ideas for improving fuel combustion efficiency and technical support for the preparation of clean fuels.

E. Coli inactivation by humidified air barrier discharge plasmas and the chemical stability of amino acids

Abstract In this study, we use atmospheric air dielectric barrier discharge (DBD) plasma to inactivate Escherichia coli (E. coli) by changing the air humidity levels. In order to analyze the inactivation process of E. coli during the humidified air DBD plasma treatment, we analyze the byproducts of 12 representational amino acids and compare their chemical stability. The experimental results show that the E. coli surface density (CFU/cm2) on a steel disc decreased significantly when the air humidity was increased from 20% to 60%, and humidified air DBD plasma at 60% humidity is very effective in inactivating E. coli. A consistently potent deactivation effect on E. coli can be seen in plasma afterglow treatment experiments over a storage time of two minutes, indicating that plasma-activated long-lived reactive oxygen and nitrogen species play a crucial role in controlling the E. coli inactivation. Compared to the low humidity (20%) condition, the concentration of reactive species produced by the plasma at high humidity (60%) increased 2-fold for 2-hydroxyterephthalic acid and 5-fold for hydrogen peroxide while ozone production was halved. Amino acid experiments showed that amino acids may be oxidized, hydroxylated and nitroxylated by reactive species. The reduction of amino acids by air DBD plasma was even more pronounced at high air humidity compared to low air humidity. Our analysis indicates that the significant inactivation of E. coli by humified air DBD plasma is related to the chemical instability of amino acids.

Destruction of n-hexane from the air stream by pulsed discharge plasma: Modelling and key process parameters optimization by CCD-RSM

In this study, a Dielectric-Barrier Discharge (DBD) plasma reactor was used for the degradation of n-hexane from an air stream. a Central Composite Design (CCD) based Response Surface Methodology (RSM), (CCD-RSM) was utilized to explore the effects of experimental parameters including discharge voltage, initial concentration, gas flow rate, relative humidity and their interactions on the reactor performance. The proposed optimization model showed a satisfactory correlation between the predicted and actual results. According to the results, discharge voltage was the most significant parameter affecting the removal efficiency, CO2 selectivity and the level of O3 and NOx formation, whereas energy yield was mainly influenced by gas flow rate and initial concentration. At optimized conditions (discharge voltage of 8.5 kV, inlet concentration of 94.3 ppm, relative humidity of 55 % and gas flow rate of 733.16 ml/min with combined desirability of 0.921), removal efficiency of 92.57 %, CO2 selectivity of 58.87 %, energy efficiency of 0.25 g/kWh, O3 formation of 140.88 mg/m3 and NOx formation of 122.46 ppm were obtained. Water vapour significantly increased the removal efficiency and CO2 selectivity as well as reduced O3 and NOx. The results revealed that the CCD-RSM provided the optimum process parameters for the Non-Thermal Plasma (NTP) system.

Effect of dielectric barrier discharge (DBD) plasma treatment on physicochemical and 3D printing properties of wheat starch

In recent years, the focus has shifted towards carbohydrate-based hydrogels and their eco-friendly preparation methods. This study involved an investigation into the treatment of wheat starch using dielectric barrier discharge (DBD) plasma technology over varying time gradients (0, 2, 5, 10, 15, and 20 min). The objective was to systematically examine the impact of different treatment durations on the physicochemical properties of wheat starch and the suitability of its gels for 3D printing. Morphology of wheat starch remained intact after DBD treatment. However, it led to a reduction in the amylose content, molecular weight, and crystallinity. This subsequently resulted in a decrease in the pasting temperature and viscosity. Moreover, the gels of the DBD-treated starch exhibited superior 3D printing performance. After a 2-min DBD treatment, the 3D printed samples of the wheat starch gel showed no significant improvements, as broken bars were evident on the surface of the 3D printed graphic, whereas DBD-20 showed better printing accuracy and surface structure, compared to the original starch without slumping. These results suggested that DBD technology holds potential for developing new starch-based gels with impressive 3D printing properties.

Nanosized curing catalyst via nano-templated plasma PVD for attaining superior low-cure powder coating films

The addition of curing catalysts into powder coating is a key method to fabricate low-temperature curing powder coating for reducing energy consumption and expanding its applications to heat-sensitive substrates. However, the heterogeneous dispersion of the unmodified catalysts in powder coatings results in inconsistent catalysis of resin crosslinking, thus leading to compromised surface smoothness and gloss. Utilizing nanosized catalysts is an efficient solution to such problems. In this paper, we propose a nano-templated dielectric barrier discharge (DBD) plasma-assisted physical vapor deposition (PVD) strategy to fabricate the nanosized catalysts. The curing catalyst, 2-ethylimidazole (2-elm), is successfully vaporized and deposited on nano-carrier SiO2 (SiO2-NPs) in the DBD plasma reactor at atmospheric pressure, producing 2-elm@SiO2-NPs. The mechanical strength and chemical resistance of finishes of powder coating incorporated with the 2-elm@SiO2-NPs remained at low curing temperature (170 °C for 15 min) and fast curing condition (190 °C for 8 min). In addition, their surface qualities are comparable to that of the original powder coating, with up to 100 % gloss retention, successfully eliminating the issue of more than 25 % gloss attenuation of the powder coating with unmodified 2-elm. This study provides an effective, solvent-free strategy for fabricating nanosized curing catalysts and achieving high-quality film finishes.

Effect of the component and the concentration ratio on the removal of volatile organic compound mixtures by non-thermal plasma

Abstract The feasibility and efficiency of the degradation of volatile organic compounds (VOCs) by non-thermal plasmas(NTP) has been extensive investigated and proved in laboratory experiments with single target component. In practical, multicomponent VOCs are emitted during industrial production. It is urgent need to study the abatement of multicomponent VOCs to evaluate the effectiveness of NTP technology in application, and explore the impact of interactions between VOCs components on degradation efficiency. This study focused on the degradation of VOCs mixtures composed of toluene (TOL), acetone (AC), and ethyl acetate (EA) by dielectric barrier discharge (DBD) plasma in room temperature. Through changing the target gas in turn and the concentration ratio of additive gas in binary mixture, the influence of the composition and the concentration ratio of the additive gases on the target gas degradation have been investigated by comparing the decomposition of the single compound. The results showed that AC and EA had little or no inhibitory effect on degradation of TOL. When AC was added and degraded together with TOL, the degradation rate of TOL remained almost unchanged with slight fluctuations in the range of 75.3 ± 1.0% as the ratio of added AC increased. However, TOL significantly inhibited the degradation of EA, and AC, and more seriously on AC. When the ratio of added TOL increased, the degradation rates of EA or AC changed from 41.1% or 34.5% to 29.8% or 12.2%, which were 11.3% or 22.3% reduced respectively. It’s indicated that there was a mutual inhibitory effect between the AC and EA when they were degraded together, and a stronger inhibitory effect of EA on AC was observed. When the ratio of added AC to EA changed from 0:1 to 3:1, the degradation rate of EA decreased by 9.5%, from 49.8% to 40.3%. When the ratio of added EA to AC changed from 0:1 to 3:1, the degradation rate of AC decreased by 16.0%, from 37.9% to 21.9%.

Optimizing electrode arrangement in plasma actuators: a study on induced velocity and efficiency

This study investigates the performance of two types of multi-encapsulated electrode (MEE) plasma actuators, compared to typical dielectric barrier discharge (DBD) plasma actuators, in quiescent air. The objective is to determine whether the multiple encapsulated structure can enhance the performance of the plasma actuator. In the present paper, flow characteristics are investigated by using particle image velocimetry (PIV) and Schlieren visualisation. In addition, the distribution of body force over the gas volume based on the Navier–Stokes equations is calculated from velocity measurements. The obtained results demonstrate that the starting vortex behavior is influenced by electrode arrangement. Specifically, it can be observed that when the first encapsulated electrode is positioned closer to the exposed electrode, then a significantly higher induced velocity can be obtained compared to the baseline condition. In fact, the induced velocity can be increased by up to 1.5 times under this optimize configuration. These results highlight the importance of electrode arrangement in the plasma actuator design. Based on body force estimation, MEE plasma actuators exhibit a significantly higher momentum transfer, particularly in the wall normal direction. The investigation on the mechanical efficiency also reveals that the optimized configuration proposed in the present study can significantly enhance the efficiency. In fact, a four-fold increase in maximum efficiency compared to the typical configuration is observed. These results suggest that the proposed configuration could be considered a promising solution for improving the mechanical efficiency of plasma actuators.

Surface modification of polymers by 50 Hz dielectric barrier discharge (DBD) plasma produced in air at 40 Torr

This study deals with the surface modification of polymer films utilizing a custom designed cost- effective dielectric barrier discharge (DBD) plasma produced in air at reduced pressure. We comprehensively examine diverse aspects of surface modification, encompassing electrical discharge characterization, optical signal analysis, contact angle measurements, and surface morphology assessment. Our observations unveiled the presence of distinctive filamentary streamer-based micro-discharges during the DBD process, with a power consumption of approximately 5.64 watts and an electron density of 3.4 × 1011 cm−3. Optical emission spectroscopy identifies multiple emission peaks attributed to nitrogen emissions. Notably, plasma treatment substantially reduced the water contact angle and augmented surface energy on polypropylene (PP) and polyethylene terephthalate (PET) films. Surface morphology analysis illustrated an increase in surface roughness following plasma treatment. Intriguingly, the initial rapid alterations in wettability and surface morphology attained equilibrium after approximately 30 seconds of treatment. This study highlights atmospheric DBD plasma's effectiveness in customizing polymer surfaces, improving wettability and roughness, offering promising applications for enhanced adhesion and wetting.

Human coronavirus 229E inactivation on porous and nonporous materials using dielectric barrier discharge (DBD) plasma.

Viruses can spread through contaminated aerosols and contaminated surface materials, and effective disinfection techniques are essential for virus inactivation. Nonthermal plasma-generated reactive oxygen and nitrogen species can effectively inactivate the coronavirus. We aim to interpret the coronavirus inactivation level and mechanism of surface interaction with materials with and without dielectric barrier discharge (DBD) plasma treatment. Nonthermal plasma, particularly surface-type DBD plasma, can inactivate human coronavirus 229E (HCoV-229E) on porous (paper, wood, mask) and nonporous (plastic, stainless steel, glass, Cu) materials. Virus inactivation was analyzed using a 50% tissue culture infectivity dose (TCID50) using cell line, flow cytometry, and immunofluorescence. Surfaces contaminated with HCoV-229E were treated at different time intervals (0-5 h) with and without plasma exposure (natural decay in ambient air conditions). HCoV-229E persistence conformed to the following order: plastic > cover glass > stainless steel > mask > wood > paper > Cu with and without plasma exposure. HCoV-229E was more stable in plastic, cover glass, and stainless steel in 5 h, and the viable virus titer gradually decreased from its initial log10 order of 6.892 to 1.72, 1.53, and 1.32 TCID50/mL, respectively, under plasma exposure. No virus was observed in Cu after treatment for 5 h. The use of airflow, ambient nitrogen, and argon did not promote virus inactivation. Flow cytometry and immunofluorescence analysis demonstrated a low expression level of spike protein (fluorescence intensity) during plasma treatment and in E and M genes expression compared with the virus control.

Optimisation of plasma-activated water: Plasma DBD technology and application in recirculating aquaculture system for Nile tilapia larval culture

Plasma-activated water (PAW) is a useful tool for producing pathogen-free seed fish. This study aimed to apply dielectric barrier discharge (DBD) plasma to reduce the microbial population in the water of a recirculating aquaculture system (RAS) for Nile tilapia larval culture. Initially, a PAW system prototype was developed and found to effectively reduce bacterial populations in both stagnant and circulating water. Additionally, a slight increase in water temperature was observed in the circulating water. Subsequently, the optimisation of PAW conditions in the circulating water was performed. The PAW system, with a copper anode distance of 2 cm and a 1 cm distance between the copper tip and the water surface, combined with a non-spaced cathode pad, exhibited the highest bactericidal effect. Using the optimised PAW conditions from Experiment I, Nile tilapia larval culture was established in the RAS, supplemented with a bacterial suspension (Bacillus subtilis, Streptococcus agalactiae and Aeromonas hydrophila) to assess the bactericidal effects. Three treatments were applied: 1) control (no PAW or antibiotics), 2) PAW, and 3) antibiotic treatment for Nile tilapia larvae cultured in the RAS system for 672 h. The results demonstrated that both PAW and antibiotic treatments significantly reduced the bacterial populations in the water in relation to the control (P < 0.05). Moreover, a substantial reduction in bacterial population was observed in the whole body of the fingerlings in both the PAW and antibiotic groups in relation to the control fingerlings (P < 0.05). In Experiment II, Nile tilapia larval culture in the RAS was conducted under three different conditions: 1) control (no PAW or antibiotic), 2) PAW, and 3) antibiotic treatment, to evaluate the antimicrobial effects of PAW on waterborne bacterial populations for 672 h. Similar to Experiment I, both antibiotic and plasma treatments significantly reduced the bacterial populations in the water and whole-body fingerlings in relation to the control (P < 0.05). Notably, the growth performance and whole-body composition (moisture, crude protein, crude fat, and ash) of the fingerling fish appeared comparable among the experimental groups (P > 0.05), suggesting that PAW had no detrimental effects on long-term fish culture. Therefore, PAW can be employed to effectively reduce bacterial populations in water, thus minimising bacteria-related issues in fish without adverse impacts on fish growth.

Study on the Control Mechanism of DBD-PA on Near Wall Flow

Based on the Shyy plasma simulation model, this paper studied the control mechanism of positive and reverse DBD-PA (dielectric barrier discharge plasma actuator) on near wall flow, and discussed the influence of incoming boundary layer thickness and parallel double DBD-PA on control effect. The results showed that: the positive DBD-PA had an obvious acceleration effect on the near wall flow field, and the acceleration effect first increased and then decreased; the reverse DBD-PA had an obvious deceleration effect on the near wall flow field, and the deceleration effect decreased gradually; increasing the thickness of the incoming boundary layer can improve the control effect, but the improvement effect is gradually reduced; when parallel double DBD-PA, the control effect of positive and reverse DBD-PA is improved by 88.7 % and 62.5 % respectively.

Virtual leading-edge aero-shaping of an airfoil using a dielectric barrier discharge plasma actuator

Recently, it has been demonstrated that dielectric barrier discharge plasma actuators, which can be capable of generating a quasi-steady wall jet under the effect of a sinusoidal power supply, are well suitable for controlling the flow around the airfoil at a low Reynolds number. To uncover the controlling mechanism of plasma actuators, flow separation control over an SC (2)-0714 supercritical airfoil using an asymmetrical plasma actuator arranged at the leading edge of the airfoil, is studied at Reynolds number of 7.8 × 104. The stall angle of attack is delayed from 9° to 13°, and the maximum lift coefficient is increased by about 27%. In addition to the momentum injection to the boundary layer, which is one of the control mechanisms and can be achieved by the induced spanwise vortex of the plasma actuator, the closed recirculation region, which is similar to superimposing a hump on the leading edge of the airfoil, is another control mechanism, leading to an increase in the effective camber of the airfoil. The localized recirculation zone, which is created by the plasma actuator and modifies the leading-edge aero-shaping and results in the enhancement of the lift coefficient, is first observed, and this effect of the plasma actuator is called the virtual leading-edge aero-shaping.

Influence of air DBD plasma treatment on the shear and flexural strength of adhesively bonded glass fiber reinforced epoxy composite joints

In this study, air dielectric barrier discharge (DBD) plasma treatment was applied at various voltages and treatment durations to improve the bonding strength of glass fiber reinforced epoxy composites (GF/EP). In addition, single lap shear and three-point bending strengths of adhesively bonded joints were compared between untreated and surface-treated (sanding, peel ply, and plasma) samples. Surface properties of GF/EP composites were examined using contact angle, surface free energy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Atomic Force Microscopy (AFM). Then, mechanical tests (single lap shear and three point bending) were performed and the damage modes were determined. Surface analyses revealed that wettability and polar functional groups increased on the GF/EP surface after plasma treatment. From the mechanical test results, it was observed that the plasma treatment applied to GF/EP composites increased both single lap shear and flexural strength compared to untreated, sanding and peel ply surface treatments. After both single lap shear and 3-point bending tests, adhesive, and light fiber tear failure modes were observed.

Metal–organic framework–derived trimetallic particles encapsulated by ultrathin nitrogen-doped carbon nanosheets on a network of nitrogen-doped carbon nanotubes as bifunctional catalysts for rechargeable zinc–air batteries

Economical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) bifunctional catalysts with high activity aimed at replacing precious metal catalysts for rechargeable zinc-air batteries (ZABs) must be developed. In this study, a multiple hierarchical-structural material is developed using a facile dielectric barrier discharge (DBD) plasma surface treatment, solvothermal reaction, and high-temperature carbonization strategy. This strategy allows for the construction of nanosheets using nitrogen-doped carbon (NC) material-encapsulated ternary CoNiFe alloy nanoparticles (NPs) on a network of NC nanotubes (NCNTs), denoted as CoNiFe–NC@p–NCNTs. Precisely, the presence of abundant CoNiFe alloy NPs and the formation of M–N–C active sites created by transition metals (cobalt, nickel, and iron) coupled with NC can provide superior OER/ORR bifunctional properties. Moreover, the prepared NC layers with a multilevel pore structure contribute to a larger specific surface area, exposing numerous active sites and enhancing the uniformity of electron and mass movement. The CoNiFe0.08–NC@p–NCNTs show remarkable dual functionality for electrochemical oxygen reactions (ORR half-wave potential of 0.811 V, limiting current density of 5.73 mA cm−2 measured with a rotating disk electrode at a rotation speed of 1600 rpm, and OER overpotential of 351 mV at 10 mA cm−2), which demonstrates similar ORR performance to 20 wt% Pt/C and better OER performance than the commercial RuO2. A liquid ZAB prepared using the proposed material has excellent bifunctionality with an open-circuit voltage of 1.450 V and long-term cycling stability of 230 h@10 mA cm−2.

Enhanced norfloxacin removal from sludge by dielectric barrier discharge plasma synthesis with Fe3O4/g-C3N4

The excess sludge adsorbed with antibiotics poses a huge threat to the ecological environment and human health, and the removal of antibiotics from sludge was focused on. The dielectric barrier discharge (DBD) coupled with Fe3O4/g-C3N4 to degrade norfloxacin (NOR) in excess sludge of wastewater treatment plant was studied, where Fe3O4/g-C3N4 was prepared through high-temperature calcination. At an input voltage of 90 V and at a current of 0.5 A, NOR concentration of 100 mg/kg total suspended solids (TSS), Fe3O4/g-C3N4 dosing of 100 mg/g TSS, and pH 6.94, the NOR degradation efficiency was 89.2 %, the energy yield was 1.98 mg/kWh, and the synergy factor of DBD with Fe3O4/g-C3N4 was 1.85. In this system, •OH, •O2−, h+, H2O2 and O3 played an important role in the degradation of NOR in sludge, and Fe3O4/g-C3N4 induced Fenton-like reactions using H2O2 generated by DBD and facilitated photocatalytic reactions with ultraviolet and visible light. There was a positive correlation between the NOR degradation efficiency and the sludge disintegration, and the sludge disintegration process released NOR from the solid phase to the liquid phase. Three possible degradation pathways and the toxicity evaluation of the intermediates were proposed based on the results of DFT and HPLC-MS. Additionally, the DBD/Fe3O4/g-C3N4 system improved the sludge disintegration and dewatering performance effectively.

Performance enhancement for direct borohydride fuel cells through ternary Ru–Co–B oxide catalyst

Dielectric barrier discharge (DBD) plasma is used to prepare ternary heterostructured Ru–Co–B oxide catalyst with considerable RuO2/CoO/B20H26O interface and oxygen vacancy (Ov) for enhanced borohydride oxidation reaction. the Ru–Co–B catalyst displayed remarkable electrocatalytic activity and long-term stability Due to the difference in energy band structure at the interface where the charge distribution is not homogeneous, the heterogeneous structure will spontaneously generate a built-in electric field which prompts the interfacial charge transfer. The production of Ov increases its active site and promotes its catalytic activity. While it is used in membrane-less direct borohydride fuel cells (DBFCs), it showed a peak power density of 206 mW cm−2 at room temperature and a remarkable stability of 270 h at a constant current of 20 mA that is superior to commercial Pt/C.

Efficient simultaneous removal of diesel particulate matter and hydrocarbons from diesel exhaust gas at low temperatures over Cu–CeO2/Al2O3 coupling with dielectric barrier discharge plasma

Diesel particulate matter (DPM) and hydrocarbons (HCs) emitted from diesel engines have a negative affect on air quality and human health. Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem. In this study, Cu-doped CeO2 loaded on Al2O3 coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs. Removals of DPM and HCs at 200 °C using the catalyst were as high as 90% with plasma but below 30% without plasma. Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process. It was found that Cu–CeO2 can promote the formation of adsorbed oxygen ( – ) and terminal oxygen (M=O), which can react with DPM to form carbonates that are easily converted to gaseous CO2. Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.

Preventing thermal aggregation of ovalbumin through dielectric-barrier discharge plasma treatment and enhancing its emulsification properties

The impact of Dielectric-Barrier Discharge (DBD) plasma treatment on the prevention of heat-induced aggregation of Ovalbumin (OVA) and improvement in emulsification properties was investigated. Results highlighted the effective inhibition of thermal aggregation of OVA following exposure to plasma. Structural analysis revealed that the plasma-induced oxidation of sulfhydryl and intermolecular disulfide bonds played a pivotal role in inhibiting the thermal aggregation, considered by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE), multiplies spectroscopy, and analysis of dynamic exchange of sulfhydryl-disulfide bonds. Meanwhile, the oxidation of exposed hydrophobic sites due to plasma treatment resulted in the transformation of the OVA molecule's surface from hydrophobic to hydrophilic, contributing significantly to the aggregation inhibition. Additionally, compared to an untreated sample of OVA, almost one-fold increase in emulsifying ability (EAI) and 1.5-fold in emulsifying stability (ESI) was observed after 4 min of plasma treatment. These findings demonstrated that plasma treatment not only enhanced the thermal stability of OVA, but also improved its emulsification properties.

Engineering Nano-Sized Silicon Anodes with Conductive Networks toward a High Average Coulombic Efficiency of 90.2% via Plasma-Assisted Milling.

Si-based anode is considered one of the ideal anodes for high energy density lithium-ion batteries due to its high theoretical capacity of 4200 mAh g-1. To accelerate the commercial progress of Si material, the multi-issue of extreme volume expansion and low intrinsic electronic conductivity needs to be settled. Herein, a series of nano-sized Si particles with conductive networks are synthesized via the dielectric barrier discharge plasma (DBDP) assisted milling. The p-milling method can effectively refine the particle sizes of pristine Si without destroying its crystal structure, resulting in large Brunauer-Emmett-Teller (BET) values with more active sites for Li+ ions. Due to their unique structure and flexibility, CNTs can be uniformly distributed among the Si particles and the prepared Si electrodes exhibit better structural stability during the continuous lithiation/de-lithiation process. Moreover, the CNT network accelerates the transport of ions and electrons in the Si particles. As a result, the nano-sized Si anodes with CNTs conductive network can deliver an extremely high average initial Coulombic efficiency (ICE) reach of 90.2% with enhanced cyclic property and rate capability. The C-PMSi-50:1 anode presents 615 mAh g-1 after 100 cycles and 979 mAh g-1 under the current density of 5 A g-1. Moreover, the manufactured Si||LiNi0.8Co0.1Mn0.1O2 pouch cell maintains a high ICE of >85%. This work may supply a new insight for designing the nano-sized Si and further promoting its commercial applications.

Different Methods to Modify the Hydrophilicity of Titanium Implants with Biomimetic Surface Topography to Induce Variable Responses in Bone Marrow Stromal Cells.

The osteoblastic differentiation of bone marrow stromal cells (bMSCs), critical to the osseointegration of titanium implants, is enhanced on titanium surfaces with biomimetic topography, and this is further enhanced when the surfaces are hydrophilic. This is a result of changing the surface free energy to change protein adsorption, improving cell attachment and differentiation, and improving bone-to-implant contact in patients. In this study, we examined different methods of plasma treatment, a well-accepted method of increasing hydrophilicity, and evaluated changes in surface properties as well as the response of bMSCs in vitro. Commercially pure Ti and titanium-aluminum-vanadium (Ti6Al4V) disks were sand-blasted and acid-etched to impart microscale and nanoscale roughness, followed by treatment with various post-processing surface modification methods, including ultraviolet light (UV), dielectric barrier discharge (DBD)-generated plasma, and plasma treatment under an argon or oxygen atmosphere. Surface wettability was based on a sessile water drop measurement of contact angle; the elemental composition was analyzed using XPS, and changes in topography were characterized using scanning electron microscopy (SEM) and confocal imaging. The cell response was evaluated using bMSCs; outcome measures included the production of osteogenic markers, paracrine signaling factors, and immunomodulatory cytokines. All plasma treatments were effective in inducing superhydrophilic surfaces. Small but significant increases in surface roughness were observed following UV, DBD and argon plasma treatment. No other modifications to surface topography were noted. However, the relative composition of Ti, O, and C varied with the treatment method. The cell response to these hydrophilic surfaces depended on the plasma treatment method used. DBD plasma treatment significantly enhanced the osteogenic response of the bMSCs. In contrast, the bMSC response to argon plasma-treated surfaces was varied, with an increase in OPG production but a decrease in OCN production. These results indicate that post-packaging methods that increased hydrophilicity as measured by contact angle did not change the surface free energy in the same way, and accordingly, cells responded differently. Wettability and surface chemistry alone are not enough to declare whether an implant has an improved osteogenic effect and do not fully explain how surface free energy affects cell response.