Li-ion batteries with “nickel” as the main material or the highest ratio material on the cathode or anode electrode have attracted considerable attention. Nickel has high strength and corrosion resistance. Nickel has also been utilized successfully as the cathode and anode materials. The specific capacity and energy and power density of the material increased with increasing nickel content. However, several problems have limited the use of nickel-based Li-ion batteries. Problems such as cation mixing, the properties of nickel, and highly Ni-rich compounds leading to side reactions, influence the electrochemical performance of Li-ion batteries. The morphology is another factor affecting the electrochemical performance. Further studies will be needed to synthesize materials with the desired morphology and determine how the morphology affects the electrochemical performance. In a morphological perspective, extensive morphological adjustments are a pathway to a long and stable life cycle. In this light, nickel-based electrodes are manufactured continuously and will always be considered for next-generation secondary energy storage. The morphology of nickel-based active materials is one of the main factors determining the high-performance of Li-ion batteries.
Nickel is set to play a pivotal role in the next chapter of energy storage. Over the next decade, nickel-based Li-ion batteries are expected to dominate the battery market for both energy storage systems (ESS) and electric vehicles. One of the key features of nickel-based active materials is their morphology; the shape and size of the particles can affect the electrochemical performance of the active materials. Both nickel-containing anode and cathode materials with excellent morphology have been reported to have high capacity, excellent cycle stability, and rate-ability. These key performance metrics demonstrate the promising future for the development of a clean and sustainable energy industry.
While the formulation of pharmaceuticals as liquids is common practice, powders are associated with enhanced stability, avoidance of the cold chain, lower dosing requirements, and more convenient administration. These are particularly critical for proteins, as they are expensive and complicated to manufacture. Powders also have improved aerosol properties for pulmonary delivery. Conventional techniques for formulating powders include spray-drying, shelf freeze-drying, spray freeze-drying, and spray freezing into liquid, but they produce powders with poor aerosol performance and/or activity due to suboptimal powder properties. Thin-film freezing (TFF) is a new cryogenic technique that can engineer highly porous, brittle, powder matrices with excellent aerosol performance properties and stability. Herein, we describe TFF in comparison to other cryogenic techniques. Physical properties of TFF powders such as morphology, moisture sorption, stability, solubility, and dissolution, as well as aerosol properties are discussed. In addition, factors that significantly affect the physical and aerosol properties of dry powders prepared by TFF, such as solids content, drug loading, solvent system, excipient, and dry powder delivery device, are analyzed. Finally, we provide evidence supporting the applicability of using TFF to prepare dry powder formulations of protein-based pharmaceuticals, enabling their cold chain-free storage as well as efficient pulmonary delivery.
Pharmaceutical dry powders with desired aerosol properties are required for efficient pulmonary drug delivery. Thin-film freezing (TFF) followed by lyophilization is a particle engineering technology that produces highly porous, brittle, powder matrices with excellent aerosol properties and high drug loading. In this review article, the authors describe the TFF technology and discuss the physical and aerosol properties of TFF powders as well as factors affecting those properties. Finally, the authors provide a comprehensive review of published literature for applying the TFF technology to prepare aerosolizable dry powders of protein-based pharmaceuticals for pulmonary delivery.
Particle breakage occurs in comminution machines and, inadvertently, in other process equipment during handling as well as in geotechnical applications. For nearly a century, researchers have developed mathematical expressions to describe single-particle breakage having different levels of complexity and abilities to represent it. The work presents and analyses critically a breakage model that has been found to be suitable to describe breakage of brittle materials in association to the discrete element method, either embedded in it as part of particle replacement schemes or coupled to it in microscale population balance models. The energy-based model accounts for variability and size-dependency of fracture energy of particles, weakening when particles are stressed below this value, as well as energy and size-dependent fragment size distributions when particles are stressed beyond it, discriminating between surface and body breakage. The work then further validates the model on the basis of extensive data from impact load cell and drop weight tests. Finally, a discussion of challenges associated to fitting its parameters and on applications is presented.
Single-particle breakage studies were, in the not-so-distant past, only of academic interest, since no tools were available to transfer the microscale information they provide to deal with problems in industry. Fortunately, the discrete element method (DEM), along with properly-formulated population balance models, not make it possible to carry information from single particles to predict the performance of crushers, mills and handling systems that may cause their mechanical degradation. The work critically analyzes one model that has been found quite powerful in this task.
Microspheres composed of poly (lactic-co-glycolic acid) (PLGA) were formed in liquid droplets using the electrospray technique. The structure of the microspheres was controlled by changing the electric voltage of the electrospray. PLGA microspheres with porous structures and micro-sized nanocomposite particles comprising PLGA nanosphere aggregates were formed at 5.0–7.0 kV and 2.5–3.5 kV, respectively. The structural change was related to the extent of evaporation of the solvent from the droplets during their flight. When the evaporation was completed in the relatively small droplets, the microspheres with porous structures were formed in the droplets. To study the mechanism, we observed the effects of the electric voltage of the electrospray, PLGA concentration, flight distance of the droplets, and molecular weight of PLGA on the structure of the PLGA particles. The novelty of this study is the analysis of the size and structure of the PLGA microparticles, which were controlled by the electrospray technique. Therefore, this research has important implications for the structural design and preparation of nanocomposite particles.
Delivery systems using nanoparticles and microparticles composed of biodegradable polymers such as polylactic glycolic acid have attracted much attention in the pharmaceutical and cosmetic fields to the delivery of active ingredients into the body. This paper describes a novel microparticle preparation method using fine-charged droplets as reaction fields generated by electrospray. This method is unique and impactful because tailored PLGA microspheres with various sizes and different structures such as porous and solid structures can be prepared by controlling the process conditions. The formation mechanism of particles with different sizes and structures within the droplets is also explained.
A workflow for developing a multidimensional, linear correlation between the process conditions during fluidized bed spray granulation and the surface morphology of the resulting granules is presented. Spray coating experiments with Cellets®500 particles and sodium benzoate solution were performed in a lab-scale fluidized bed varying liquid spray rate, fluidization air flow rate, fluidization air temperature, spray air temperature and spray atomization pressure. To characterize the surface structure, the surface roughness of the coated particles was quantified using confocal laser-scanning microscopy. The roughness was correlated to the process conditions, and the resulting correlation was rigorously analyzed for the importance and co-linearities of the individual process parameters using a principal component analysis. The surface roughness is strongly dependent on the spray rate of the coating solution, the fluidization air temperature and the atomization pressure at the nozzle. In general, wet process conditions and large droplets with a low initial velocity favor the formation of particles with a rough surface structure, while dry conditions and fine droplets with a high velocity result in granules with a smooth and compact coating layer.
Due to their easy handling, transport, and storage compared to liquids and gases, solid products in particulate form are of great interest in both, daily life and industrial applications. Along with the high demand for those products comes the need for a thorough understanding of particle production and modification processes, like fluidized bed spray granulation, to achieve the desired product properties. To contribute to that process understanding and to, in the long term, enable the production of tailor-made particles, this study aims to correlate process parameters and particle surface structure in fluidized bed spray granulation.
On the Relationship between Torque and Flow Structure in Powder Mixers
Released on J-STAGE: May 30, 2014 | Volume 19 Pages 118-130
Bruno Laurent, John Bridgwater
A Review of the Fire and Explosion Hazards of Particulates
Released on J-STAGE: February 27, 2014 | Volume 31 Pages 53-81
Saul M. Lemkowitz, Hans J. Pasman