Sputtering Coating of Lithium Fluoride Film on Lithium Cobalt Oxide Electrodes for Reducing the Polarization of Lithium-Ion Batteries

Lithium cobalt oxide (LCO) is the most widely used cathode materials in electronic devices due to the high working potential and dense tap density, but the performance is limited by the unstable interfaces at high potential. Herein, LiF thin film is sputtered on the surface of LCO electrodes for enhancing the electrochemical performance and reducing the voltage polarization. The polarization components are discussed and quantified by analyzing the relationship between electrochemical polarization and charger transfer resistance, as well as that between concentration polarization and Li-ion diffusion coefficients. In addition, the decreased charge transfer resistance, increased lithium-ion diffusion coefficients, and stabilized crystal structure of LiF-coated LCO are confirmed by various electrochemical tests and in-situ XRD experiments. Compared to that of pristine LCO, the capacity and cycling performance of LiF-coated LCO is improved, and the overpotential is reduced upon cycling. This work provides reference for quantifying the various polarization components, and the strategy of coating LiF film could be applied in developing other analogous cathode materials.

Characterization of Moringa oleifera Leaf Powder Extract Encapsulated in Maltodextrin and/or Gum Arabic Coatings

The encapsulation of bioactive-rich plant extracts is an effective method of preventing their damage or loss of activity during processing and storage. Here, the techno-functional properties of microcapsules developed from Moringa oleifera leaf powder (MoLP) extract (core) with maltodextrin (MD), gum Arabic (GA), and a combination (MDGA) (coatings) were assessed. The bulk and tap density were 0.177, 0.325 and 0.297 g/mL and 0.13, 0.295 and 0.259 g/mL for GA, MD and MDGA microcapsules, respectively. Flowability properties of microcapsules indicated an intermediate flow except for GA which had a poor flow. The moisture content of the microcapsules ranged from 1.47% to 1.77% with no significant differences (p > 0.05) observed. All the microcapsules had high water solubility (86.35% for GA to 98.74% for MD and 90.51% for MDGA). Thermogravimetric analyses revealed that encapsulation enhanced the thermal stability of the core material. The X-ray diffraction analysis revealed that the microcapsules and extracts have an amorphous nature, which was validated by the surface morphology analysis that showed amorphous, irregular, and flake-like attributes except for MDGA microcapsules which had slightly spherical and agglomerated surfaces. The Fourier Transform Infra-Red spectra of the microcapsules showed the presence of C-O and O-H aromatic rings as well as amine groups. New spectra were observed at 1177, 1382 and 1411 cm−1 for MDGA, MD and GA, respectively, after encapsulation, which connotes a slight modification in the chemical structural pattern after encapsulation. Storage stability tests (28 days at 4, 25 and 40 °C) showed that the microcapsules were most stable at 4 °C and the stability differs significantly (p ≤ 0.05) with coating material type and temperature with MDGA showing better storage stability than others. Altogether, the attributes of the MDGA microcapsules were comparatively better than either MD or GA alone. The present data, therefore, demonstrate an effective encapsulation process for MoLP extract that can serve as fortificants in processed food products where MoLP may be used.

Microencapsulation of steroidal saponins from agave sap concentrate using different carriers in spray drying

Concentrated agave sap is a product with in vivo proven hypocholesterolemic and hypoglycemic activities, as well as in vitro anticancer potential. In the present work, a factorial design was used to determine the suitable drying conditions of concentrated agave by studying the effect of inlet temperature (150 °C, 180 °C and 210 °C) and the type of carrier agent (maltodextrin, hydroxypropyl methylcellulose, guar gum and xanthan gum). The response variables for each treatment were the product recovery and microencapsulated saponins. Further characterization of concentrated agave powders was performed: solubility in water, hygroscopicity, moisture content, tap density, bulk density, Carr’s index followability and morphology by scanning electron microscopy analysis. The hydroxypropyl methylcellulose proved to improve physicochemical properties and enhance product yield, using 210 °C inlet temperature and a mix of carrier agents of maltodextrin/hydroxypropyl methylcellulose/xanthan gum at 50/48.5/1.5 (w/w/w) proportion exhibited the highest saponin recovery of 53.81%. Moreover, different carrier agents in powders revealed two shapes, regular spherical shape with smooth surface and collapsed shapes. The use of polymers excipients helped to decrease the stickiness of the desired product and enhanced the powder stability and microencapsulation of the steroidal saponins.

Study on Preparation Technology and Physical Fingerprint of Chuilian Jianpi Granules Based on QbD

Objective. To optimize the preparation formula and technology of Chuilian Jianpi granules. Methods. The formulation and preparation process were optimized by single factor experiment and response surface analysis, with the molding rate, hygroscopicity, and fluidity of particles as the comprehensive evaluation indexes, and the comprehensive score as the response value according to different weights. To further evaluate the stability and feasibility of the preparation formulation and technology, the physical fingerprint of the granules was constructed by seven indicators including particle tap density, bulk density, hygroscopicity, water content, angle of repose, Hausner ratio, and relative homogeneity index. Results. The optimum formula conditions of Chuilian Jianpi granules were as follows: the dosage ratio of drug to adjuvant was 1 : 0.8, lactose:mannitol = 1.5 : 1, and the amount of wetting agent (90% ethanol) was 25% of the granules, with high-speed stirring granulation. The similarity of the physical fingerprints of the 10 batches of Chuilian Jianpi granules was high, which is above 98.5%. Conclusion. The optimized preparation technology was stable and feasible, which can provide reference for the development of Chuilian Jianpi granules and other Chinese medicine granules.

Comparative Evaluation of Characterization Methods for Powders Used in Additive Manufacturing

In recent years, the interest in additive manufacturing technologies has increased significantly, most of them using powders as feedstock material. It is therefore essential to check the quality of the powder before processing in order to ensure the same quality of the printed components at all times. This kind of quality assurance of a powder should be carried out independently of the additive manufacturing technology used. Since there is a lack of standards in this field, various powder analysis methods are available, with which, in principle, the same characteristics can often be measured, at least nominally. To verify the validity of these methods, three different nickel-based powders used for additive manufacturing were examined in the present study using standard methods (apparent density, tap density, Hall flow rate, optical microscopy, scanning electron microscopy) and advanced characterization methods (dynamic image analysis, x-ray microcomputed tomography, adsorption measurement by Brunauer–Emmett–Teller method). A special focus has been given on particle size distribution, particle shape, specific surface area, and internal porosity. The results of these measurements were statistically compared. This study therefore provides an insight into the advantages and disadvantages of various optical characterization techniques.

Compaction behavior of powder bed fusion feedstock for metal and polymer additive manufacturing

Purpose Powder bed-based additive manufacturing (AM) is a promising family of technologies for industrial applications. The purpose of this study is to provide a new metrics based on the analysis of the compaction behavior for the evaluation of flowability of AM powders. Design/methodology/approach In this work, a novel qualification methodology based on a camera mounted onto a commercially available tap density meter allowed to assess the compaction behavior of a selection of AM materials, both polymers and metals. This methodology automatizes the reading of the powder height and obtains more information compared to ASTM B527. A novel property is introduced, the “tapping modulus,” which describes the packing speed of a powdered material and is related to a compression/vibration powder flow. Findings The compaction behavior was successfully correlated with the dynamic angle of repose for polymers, but interestingly not for metals, shedding more light to the different flow behavior of these materials. Research limitations/implications Because of the chosen materials, the results may lack generalizability. For example, the application of this methodology outside of AM would be interesting. Originality/value This paper suggests a new methodology for assessing the flowing behavior of AM materials when subjected to compression. The device is inexpensive and easy to implement in a quality assurance environment, being thus interesting for industrial applications.