Dry-coating Method Research Articles

Acid Mine Drainage Prevention through the Dry Coating Method Using Fly Ash and Bottom Ash

Acid Mine Drainage Prevention through the Dry Coating Method Using Fly Ash and Bottom Ash

A nickel-rich oxide, Li(Ni0.90Co0.06Mn0.04)0.995Al0.005 O2, with a dual conductive coating

Nickel (Ni)-rich layered oxides have high specific capacities and are inexpensive, but their synthesis and electrochemical performance continue to present difficulties. In this study, we investigated the effect of a dual conductive compound of dot-like Nb12WO33 and film-like lithium boron oxide (Li-B-O; applied using a simple dry-coating method) on the Ni-rich oxide layer in Li batteries. The film-like Li-B-O homogeneous coating segregated the cathode from the electrolyte, which improved the initial efficiency and cycle stability, and the dot-like Nb12WO33 provided a fast Li-ion transition channel, which improved the rate performance of the Ni-rich oxide layer. The modified cathode with dual conductive coating exhibited significantly improved electrochemical performance. Its discharge capacity was 225.6 mAh g−1, with high initial efficiency of 92.73% in the voltage range of 3.0–4.3 V at 0.1 C, whereas that of the uncoated sample was 219.4 mAh g−1, with an initial efficiency of 90.4%. The modified cathode had a discharge capacity of 179.1 mAh g−1 at 5 C, compared with that of 161.1 mAh g−1 for the uncoated sample; the capacity retention of the coated sample was 92.84% at 0.5 C after 50 cycles at 25 ℃, whereas that of the uncoated sample was only 81.41%. A similar strategy could be utilized to enhance the performance of other cathode materials.

Influence of Mixing Process on the Performance of Electrodes Made by a Dry Coating Method

Thick NMC-LMO blend positive electrodes were manufactured using dry-powder electrostatic spray deposition (ESD) to avoid the use of unwanted solvents. The effects of two dry powder mixing processes prior to ESD on the dry-made electrodes were investigated by peel tests, electrochemical techniques, and microscopic analyses. Electrodes made using high-speed mixing had a dense carbon black/binder layer on the active materials (AM), limiting their contact area with the electrolyte and decreasing the ionic conductivity. Electrodes made using ball mill mixing exhibited a porous structure, enabling more AM-electrolyte contact, thus improving ionic conductivity and lowering charge transfer resistance.

Specialised Coating Processes Finding Pharmaceutical Applicability

The manuscript aims at furnishing comprehensive information pertaining specialised coating technology/ processes. Solid dosage forms and solid particulates (SDFSP) are the major contributing group in the solid pharmaceuticals (SoPs). SDFSP exhibit peculiar physico-chemical properties and interaction behaviour which create problems/ issues during their handling, processing, storage, and use. Modifying and/or engineering surface attributes of SDFSP are advocated as powerful tool to modify their interaction behaviour and realise their worthy applications and functionalities. In this regard coating their surfaces with coating material (CM) is novel approach. Said approach involves wet and dry process for realising deposition of CM onto the surface of SDFSP substrates. Both the processes modify and/or alter innate properties of SDFSP substrates either physically or chemically. Basing on involved wet or dry process the coating method is either dry coating method (DCM) or wet coating method (WCM). Accordingly nowadays there available number of specialised devices, that bases on diverse technologies. Amongst them some involves state-of-art process/ technology like Supercell coating technology (SCT), Chemical vapour deposition (CVD), Atomic/molecular layer deposition (AMLD), Electrostatic deposition, Thermo-mechanical process, Resonant acoustic technology, Fluidised-bed process, Supercritical fluid (SCF) technology, and others. These foundational for commercially availability of specialised equipments like Magnetically Assisted Impaction Coater (MAIC), Resodyn acoustic mixer, Hybridizer®, Theta-composer®. Mechanofusion®, and others. Working and working principle, applicability, benefits, pros and limitations of specialised coating processes and technologies are herein discussed and presented. Contained information hoped to be beneficent for pharmaceutical professionals and technocrats and professionals of allied field.
 Keywords: Coating, composite product, modification, specialised, surface.

Facile Dry Coating Method of High‐Nickel Cathode Material by Nanostructured Fumed Alumina (Al2O3) Improving the Performance of Lithium‐Ion Batteries

Surface coating is a crucial method to mitigate the aging problem of high‐Ni cathode active materials (CAMs). By avoiding the direct contact of the CAM and the electrolyte, side reactions are hindered. Commonly used techniques like wet or ALD coating are time consuming and costly. Therefore, a more cost‐effective coating technique is desirable. Herein, a facile and fast dry powder coating process for CAMs with nanostructured fumed metal oxides are reported. As the model case, the coating of high‐Ni NMC (LiNi0.7Mn0.15Co0.15O2) by nanostructured fumed Al2O3 is investigated. A high coverage of the CAM surface with an almost continuous coating layer is achieved, still showing some porosity. Electrochemical evaluation shows a significant increase in capacity retention, cycle life and rate performance of the coated NMC material. The coating layer protects the surface of the CAM successfully and prevents side reactions, resulting in reduced solid electrolyte interface (SEI) formation and charge transfer impedance during cycling. A mechanism on how the coating layer enhances the cycling performance is hypothesized. The stable coating layer effectively prevents crack formation and particle disintegration of the NMC. In depth analysis indicates partial formation of LixAl2O3/LiAlO2 in the coating layer during cycling, enhancing lithium ion diffusivity and thus, also the rate performance.

Coating 1-Octanethiol-Coated Copper Nano-Ink on a Paper Substrate via Multi-Pulse Flash Light Sintering for Application in Disposable Devices

Inkjet-printed patterns were formed on a paper substrate using anti-oxidant copper nano-ink for application to disposable electronic devices. To prevent substrate damage, the pattern was flash light sintered under ambient conditions using the multi-pulse technique. Pure copper nanoparticles were coated with 1-octanethiol for oxidation resistance using the dry-coating method. Mixing these with 1-octanol solvent at a concentration of 30 wt% produced the copper nano-ink. Photo paper was used as the substrate. The contact angle between the photo paper and copper nano-ink was 37.2° and the optimal energy density for the multi-pulse flash light sintering technique was 15.6 J/cm2. Using this energy density, the optimal conditions were an on-time of 2 ms (duty cycle of 80%) for three pulses. The resistivity of the resulting pattern was 2.8 × 10−7 Ω∙m. After bending 500 times to a radius of curvature of 30 mm, the relative resistance (ΔR/R0) of the multi-pulse flash light-sintered pattern hardly changed compared to that of the unbent pattern, while the single-pulse-sintered pattern showed dramatic increase by 8-fold compared to the unbent pattern. Therefore, the multi-pulse light sintering technique is a promising approach to produce an inkjet-printed pattern that can be applied to disposable electronic devices.

Multiwalled carbon nanotube pretreatment to enhance tensile properties, process stability, and filler dispersion of polyamide 66 nanocomposites

Multiwalled carbon nanotube-dispersed polyamide 66 nanocomposites (PA66/MWCNTs) were fabricated by melt-mixing pretreated MWCNTs and PA66, and the effects of pretreating techniques and types of pretreating materials were investigated. The non-fluffy method (NFM) and the dry-coating method (DCM) were studied to determine the effects of pretreatment techniques. The tensile properties were enhanced by the NFM. However, the DCM improved the stability of the process, which greatly decreased the coefficient of variation (CV) of the physical properties. To examine the effects of pretreatment materials, an epoxy modifier (bisphenol-F diglycidyl ether; DGEBF), a fluorosurfactant (FSO100), and a silane coupling agent ((3-aminopropyl)triethoxysilane; APTES) were evaluated. Compared with DGEBF, FSO100 and APTES noticeably improved the tensile properties. However, DGEBF provided highly stable physical properties. Furthermore, the relationship between the stability of physical properties and MWCNT dispersion was investigated. Dispersion was quantified in terms of the dispersion ratio, which was determined by Voronoi diagram analysis. The dispersion ratio was inversely correlated with the CVs of the physical properties.

Surface modification of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode materials via a novel mechanofusion alloy route

This study aimed to prepare a composite coating material comprising a solid ionic conductor of lithium aluminum titanium phosphate (Li1.4Al0.4Ti1.6(PO4)3, LATP) and porous carbon through a sol-gel method. LiNi0.8Co0.1Mn0.1O2 (LNCM811) cathode material with dual-functional composite conductors (i.e., LATP@porous carbon), denoted as LATP-PC, was prepared. The dry-coating method, also called the “mechanical-fusion alloy route,” was used to modify Ni-rich LNCM811 cathode materials. X-ray diffraction (XRD), micro-Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed that the LATP ionic conductor generated herein was uniformly deposited on 3D porous carbon and served as a dual-functional composite coating on LNCM811. Furthermore, the capacity retention of LATP-PC@LNCM811 was approximately 85.57% and 80.86% after 100 cycles at −20 °C and 25 °C, respectively. By contrast, pristine LNCM811 had the capacity retention of 78% and 74.96% at −20 °C and 25 °C, respectively. Furthermore, the high-rate capability of the LATP-PC@LNCM811 material was markedly enhanced to 169.81 mAh g−1 at 10C relative to that of pristine LNCM811, which was approximately 137.67 mAh g−1. The electrochemical performance of LNCM811 was enhanced by the uniform dual-conductive composite coating. The results of the study indicate that the LATP-PC@LNCM811 composite material developed herein is a potentially promising material for future high-energy Li-ion batteries.

Improved electrochemical performances of LiNi0.6Co0.2Mn0.2O2 cathode material by reducing lithium residues with the coating of Prussian blue

Reducing the lithium residues on the surface of LiNi0.6Co0.2Mn0.2O2 (NCM) cathode is one of the most main challenges in Li-ion battery research. To address this task, a surface coating of Prussian blue (PB) of metal-organic framework is applied to NCM cathode to solve this intractable problem via a simple dry-coating method. The transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results show that the uniform smooth coating can provide a protective shell to block H2O and CO2 absorption from the air, suppressing lithium residues formed on the surface. The color change experiment between PB and Li residuals illustrates PB can react directly with surface residual lithium species. As a result, the amount of residual lithium, such as LiOH and Li2CO3, is significantly reduced. The 0.5 wt% PB-modified NCM delivers a high discharge capacity retention of 81% after 500 cycles at 1 C discharge rate and exhibits a superior storage property after storing in air for 14 days. Furthermore, electrochemical impedance spectroscopy (EIS) confirms that the PB-NCM could hinder the impedance increase during cycling. These results clearly indicate that the PB coating layer contributes to the reduction of lithium residues and the creation of thinner cathode-electrolyte interface, improving structural stability and cycling performance of NCM.

LiNi0.6Mn0.2Co0.2O2 Dry-Coated with Nano- Alumina As Positive Electrode Material

Applications of lithium ion batteries in grid storage and electric vehicle require long lifetime. Surface coating of active material is an effective way to improve the long-term cycling of lithium ion batteries.1 Most of the coating methods reported so far are wet-coating method, which produces waste liquid and requires additional drying process. In this study, LiNi0.6Mn0.2Co0.2O2 was coated with nano-alumina using a convenient dry-coating method and characterized in Li cells. Commercial LiNi0.6Mn0.2Co0.2O2 powders (obtained from Umicore) were mixed with 3% Al2O3 (13 nm, from Sigma-Aldrich) using a dry-coating method. For comparison, LiNi0.6Mn0.2Co0.2O2 powders were also mixed with 3% Al2O3 by hand-grinding. Electrodes were made with active material, PVDF binder, carbon black at a ratio of 86:7:7 and dried under vacuum at 120 ℃ overnight. 1M LiPF6 in a solution of EC and DEC (volume ratio 1:2) was used as electrolyte and Li foil was used as counter/reference electrode. Figure 1(a) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders. Secondary particles with spherical morphology were observed. The average particle size is ~1 μm for primary particle and ~10 μm for secondary particle. Figure 1(b) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders coated with 3% Al2O3 using the dry coating method. Figure 1(c) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders mixed with 3% Al2O3 by hand-grinding. The dry coating method produced a more homogeneous and dense coating, compared to materials produced by hand-grinding. Figure 2 shows the cycling performance at C/2 for all the materials cycled between 3 V – 4.4 V. Compared to pristine NMC 622, the materials processed with 3% Al2O3 displayed lower reversible capacity. However, the cycling performance was improved for both materials. Notably, materials dry-coated with 3% Al2O3 showed little capacity fade in 50 cycles. This study gives an example of using dry coating method for improving the cycling performance of positive electrode materials for lithium ion batteries. References Z. Chen et al., J. Mater. Chem., 20, 7606-7612 (2010) Figure 1

Correction to: Preparation of Controlled-Release Particles Based on Spherical Porous Silica Used as the Drug Carrier by the Dry Coating Method.

In the present notation, the formula names and the formulas (page 7, left column, lines 20-21) do not correspond to each other. It is a completely incorrect description, due to a typesetting mistake by the publisher. See below for details. The original article has been corrected.

Preparation of Controlled-Release Particles Based on Spherical Porous Silica Used as the Drug Carrier by the Dry Coating Method.

A controlled-release formulation is a dosage form that could improve a patient's quality of life by reducing the frequency of administration, while ensuring the continued effect of the medicine and reducing the side effects. To prepare these controlled-release particles, a wet coating method in which a drug is coated with a controlled-release material using water or an organic solvent is used, but with this method, the coating process is very time-consuming and requires large amounts of energy for the drying phase. In addition, contact with water or an organic solvent may cause problems such as alteration of the drug. Therefore, the use of a dry coating method has attracted attention as a means of overcoming these issues. However, since the drug is fixed to the surface of a core particle, it is necessary to further coat it with a water-soluble material. We used spherical porous silica (SPS) particles, considering that the drug fixation via a water-soluble material would not be necessary if the drug were to be placed in the pores of these particles. We used SPS filled with theophylline (TP), a model drug, as the core particles. To prepare controlled-release particles (CRP), a controlled-release layer consisting of hydrogenated castor oil (HCO) was applied to the core particle surface by a dry coating method. The paddle method using 1% w/v polysorbate 80 solution as the test medium was employed to estimate the TP dissolution rate of the resulting CRPs. The 50% dissolution time of TP extended from 14 to 405min with increasing the amount of the coated HCO. The Korsmeyer-Peppas model applied to the TP dissolution behavior yielded an n value of around 1. Moreover, the K value was comparable with the case in which a zero-order model was applied. It is thought that the dissolution of TP from CRPs will conform to the zero-order model.

Preparation of Controlled-Release Fine Particles Using a Dry Coating Method.

Wet coating methods use organic solvents to prepare layered particles that provide controlled-release medications. However, this approach has disadvantages in that it can cause particle agglomeration, reduce pharmaceutical stability, and leave residual organic solvents. We used a dry coating method to overcome these issues. Fine particles (less than 50μm in diameter) of controlled-release theophylline were created using theophylline (TP; model drug), polyethylene glycol 20,000 (PEG; drug fixative), hydrogenated castor oil (HCO; controlled-release material), hydrogenated rapeseed oil (HRSO; controlled-release material), and cornstarch (CS; core particle). An ultrahigh-speed mixer was employed to mix TP and CS for 5min at 28,000rpm. Subsequent addition of PEGproduced single-core particles with a drug reservoir coating. Addition of HCO and HRSO to these particles produced a controlled-release layer on their surface, resulting in less than 10% TP dissolution after 8h. We successfully demonstrated that this dry coating method could be used to coat 16-μm CS particles with a drug reservoir layer and a controlled-release layer, producing multi-layer coated single-core particles that were less than 50μm in diameter. These can be used to prepare controlled-release tablets, capsules, and orally disintegrating tablets.

Microencapsulation of Ascorbic Acid with Tripalmitin by Using Dry Coating Method

It was tried to microencapsulate the ascorbic acid powder as a redox initiator with tripalmitin by use of the dry coating method. In the experiment, the feed ratio of the amount of tripalmitin to that of ascorbic acid, the coating time and the concentration of ethyl alcohol of pulverizing solvent were changed stepwise. The characteristics of microcapsules such as the content of core material, the yield, the water proof degree, the microencapsulation efficiency and the mean diameter were estimated. The yield, the microencapsulation efficiency and the water proof degree gradually increased with the feed ratio, the coating time and the concentration of pulverizing solvent. The microcapsules showed the thermal responsibility and induced polymerization of methyl methacrylate monomer.

Controlled Thicknesses of Vaporized Self-Assembled Multilayers on Copper Nanopowders Under Ultra-High Vacuum (UHV)

Copper nanoparticles were coated with 1-octanethiol self-assembled monolayers (SAMs) using the dry-coating method for oxidation prevention. In this study, thicknesses of 1-octanethiol SAMs were successfully controlled, and the stability of SAMs as a passivation layer on copper nanoparticles was examined. Thicknesses of 1-octanethiol SAMs varied with vacuum levels and coating cycles. Under low-vacuum conditions, the thickness was 10 nm, regardless of the coating conditions. In contrast, various thicknesses resulted under ultra-high vacuum (UHV) and ranged from 4 nm to 10 nm. SAMs that were nearly a monolayer thick (4 nm) resulted from two coating cycles of 1.5 min, and the oxidation inhibition period was 15 days. Thus, the dry-coating method successfully controlled the thicknesses of SAMs with satisfactory oxidation inhibition properties under ultra-high vacuum.

Deposition of TiO 2 layers for dye-sensitized solar cells using nano-particle deposition system

A novel method was applied for the deposition of TiO 2 powders using Nano-Particle Deposition System (NPDS) for a dye-sensitized solar cell (DSSC). NPDS is a method used to deposit ceramic and metallic powders on substrates at room temperature by accelerating particles to subsonic speeds. In this study, TiO 2 powders were directly sprayed on transparent conductive oxide (TCO) glass at room temperature. TiO 2 powder deposition resolved problems common to conventional pastes of TiO 2 powders, such as crack formation and poor adhesion on substrates. Using this dry-coating method, the maximum light-conversion efficiency of the fabricated cell was 2.86% with a photocurrent density of 7.72 mA cm −2. The cell efficiency improved when the sealing-sheet thickness was 25 μm because the amount of electrolyte in the cell was optimized to prevent unnecessary recombination of electrons and holes. Therefore, sealing-sheet thickness is crucial in maximizing photovoltaic efficiency. Overall, this study proved that dry-coating of TiO 2 is possible for DSSC, and this method can also be applied on flexible substrates.

High Performance LiCoO2 Cathode Materials at 60 ° C for Lithium Secondary Batteries Prepared by the Facile Nanoscale Dry-Coating Method

A mass scalable dry-coating method was used on a cathode to improve cycling stability at and, in contrast to the conventional wet-coating method, this one did not require a solvent. Electrochemical results of the , , and coatings on cathodes showed a fast capacity fade, resulting in capacity retention at under 1C rate cycling, whereas an uncoated cathode showed 64% retention. This difference was believed to be because the residual coating layers which did not react with the bulk layer accelerated the side reactions with the electrolytes at , leading to increased formation of the surface films. However, when and were used for dry coating, the coating layers completely disappeared, but a higher concentration of coating elements was found near the surfaces. Overall, the cathodes coated with and exhibited 79 and 88% capacity retention, respectively, at under 1C rate cycling.

Improvement of Dissolution Property of Poorly Water-Soluble Drug by Novel Dry Coating Method Using Planetary Ball Mill

The dissolution property of a poorly water-soluble drug, flurbiprofen (FP), was improved by a novel dry coating method using a planetary ball mill. Several mixtures composed of water-soluble additives (D-mannitol, lactose, and erythritol), light anhydrous silicic acid, and flurbiprofen were prepared. These mixtures and several starches were co-ground in a planetary ball mill, and the surface of the starches was dry coated with the mixtures. The size, appearance, yield, and drug dissolution property of the dry coated preparations were evaluated, and the optimal formulation which improved the dissolution property of poorly water-soluble flurbiprofen was determined. The dissolution rate of FP was increased by dry coating of the surface of starches with microparticulated FP. It was further increased by co-grinding of FP, starch, and a water-soluble additive, or dry coating of the starch surface with microparticulated FP and light anhydrous silicic acid, as a glidant. These co-ground and dry coated preparations could be recovered from the pot of the planetary ball mill readily without adhesion to the inside wall of the pot. These are considered to be novel, industrially applicable methods for improving the dissolution rate of poorly water-soluble drugs.

Dry Coating Method Using Magnetically Assisted Impaction in a Randomly Turbulent Fluidized Bed

Dry Coating Method Using Magnetically Assisted Impaction in a Randomly Turbulent Fluidized Bed

Dry coating method for surface modification of particulates

Surface modified particulates have many potential industrial applications, ranging from new technologies such as rechargeable batteries and fiat panel displays to a wide variety of unit operation processes such as dispersion, transport and handling, and separation of particulate systems. Owing to environmental constraints, there has recently been a strong interest in the development of dry methods (chemical and/or water free) for particulate coatings. This paper reports on the feasibility of a novel dry method based on a magnetically assisted impaction process for synthesis of surface modified particulates. In this process magneticparticles in the coating system accelerate and collide with the core and secondary particles to form composite particles. Experiments have been conducted on a variety of particle systems such as Si02–SiC, CoO–Ni(OH)2, Al203–PMMA, and Ti02–Al203. The composite particles were subjected to high frequency ultrasound so that weakly adhering particles could be removed from the surface. The experiments showed that adherent uniformly distributed coatings could be formed in a wide variety of systems. Magnetically assisted impaction coatings were found to be more adherent and possess a higher surface coverage than coatings produced by standard blending methods. Preliminary experiments have also been conducted to investigate the effects of variations in materials parameterssuch as hardness of core and secondary particles.