Search Results (5)

A jet-based direct mixing process is used to effectively mix heterogeneous materials. In this work, its application in the structuring, coating and agglomeration of cathode materials for all-solid-state battery (ASSB) production is investigated, with the aim of increasing the homogeneity and conductivity of the composites and ultimately improving battery performance. In this process, different particle systems consisting of lithium iron phosphate (LFP), carbon black (CB) and sodium chloride (NaCl) are dispersed in the gas phase and brought together in a mixing zone as particle-laden aerosol jets. The cathode material’s structure is studied through scanning electron microscopy combined with a focussed ion beam (SEM–FIB). Electrical conductivity measurements of the resulting composites assess the degree of mixing and the changes in tortuosity, while a laser light diffractor and a cascade impactor analyse the particle size distribution (PSD). The jet-based process effectively produces hetero-agglomerates with the possibility of creating different composite structures by adjusting the process parameters. The mass concentration influences not only the structure, but also the PSD in the flow and the electrical conductivity of the composite. The results serve as a basis for future experiments with solid electrolytes to comprehensively evaluate the process and the resulting battery materials. Full article

The mixing transport courses of three-phase particle flows exist in some industrial applications, such as metallurgy material extraction, lithium electric slurry dispersion, and material mixing in the high-end chemical industry. Its mixing transport mechanism is a fluid–structure coupling dynamic issues with intensive shear and nonlinear characteristics, making the real-time prediction of the flow field face challenges. To address the above problem, a bidirectional fluid–structure coupling three-phase particle flow dynamic model is built based on the coupled computational fluid dynamics and discrete element model (CFD-DEM) to explore the mixing transport mechanism. An interphase coupling solution method is utilized to solve the interaction effects of the fluid and particle. Research results illustrate that the proposed method modeling can well reveal the mixing transport mechanism of the three-phase particle flows. Due to the additive effects of stirring speed, stirring blade size, and stirring blade structure, the flow field near the blade has a high-velocity gradient change, while the flow field away from the stirring blade has no significant change. When the particle material settles and accumulates to a certain extent, the particle movement is blocked, and the stirring speed of the particle material near the blade is reduced. The mixing effect of the particle material will be reduced near the wall. It can provide a valuable reference for particle flow transport and pattern identification and support technical support for lithium electric homogenate mixing, chemical extraction, and pharmacy process regulation. Full article

As the market for electric vehicles and portable electronic devices continues to grow rapidly, sodium-ion batteries (SIBs) have emerged as energy storage systems to replace lithium-ion batteries (LIBs). However, sodium-ion is heavier and larger than lithium-ion, resulting in volume expansion and slower ion transfer. It is necessary to find suitable anode materials with high capacity and stability. In addition, wearable electronics are starting to be commercialized, requiring a binder-free electrode used in flexible batteries. In this work, we synthesized nano flake-like VSe₂ using organic precursor and combined it with MWCNT as carbonaceous material. VSe₂@MWCNT was mixed homogenously using sonication and fabricated film electrodes without a binder and substrate via vacuum filter. The hybrid electrode exhibited high-rate capability and stable cycling performance with a discharge capacity of 469.1 mAhg⁻¹ after 200 cycles. Furthermore, VSe₂@MWCNT exhibited coulombic efficiency of ~99.7%, indicating good cycle stability. Additionally, VSe₂@MWCNT showed a predominant 85.5% of capacitive contribution at a scan rate of 1 mVs⁻¹ in sodiation/desodiation process. These results showed that VSe₂@MWCNT is a suitable anode material for flexible SIBs. Full article

In this work, magnetite nanoparticles (Fe₃O₄) that are well dispersed by a submicron sized carbon framework in a pomegranate shape are engineered using a flexible one-step spray pyrolysis strategy. Under inert gas atmosphere, the homogeneously mixed Fe³⁺ ions and chitosan (CS) molecules are in situ transformed to Fe₃O₄ nanoparticles and spherical nitrogen-doped carbon coating domains, respectively. Moreover, the obtained Fe₃O₄@C composite exhibits a unique submicron sized pomegranate configuration, in which favorable electric/ionic pathways have been constructed and the Fe₃O₄ nanoparticles have been effectively dispersed. When used as an anode electrochemical active material, the Fe₃O₄@C composite exhibits impressive lithium-ion storage capabilities, and maintains a reversible capacity of 500.2 mAh·g⁻¹ after 500 cycles at a high current density of 1000 mA·g⁻¹ as well as good rate capability. The strategy in this work is straightforward and effective, and the synthesized Fe₃O₄@C material has good potential in wider applications. Full article

Lithium-ion batteries have led the revolution in portable electronic devices and electrical vehicles due to their high gravimetric energy density. In particular, layered cathode material Li(Ni_0.6Mn_0.2Co_0.2)O₂ (NMC 622) can deliver high specific capacities of about 180 mAh/g. However, traditional cathode manufacturing involves high processing costs and environmental issues due to the use of organic binder polyvinylidenfluoride (PVDF) and highly toxic solvent N-methyl-pyrrolidone (NMP). In order to overcome these drawbacks, aqueous processing of thick-film NMC 622 cathodes was studied using carboxymethyl cellulose and fluorine acrylic hybrid latex as binders. Acetic acid was added during the mixing process to obtain slurries with pH values varying from 7.4 to 12.1. The electrode films could be produced with high homogeneity using slurries with pH values smaller than 10. Cyclic voltammetry measurements showed that the addition of acetic acid did not affect the redox reaction of active material during charging and discharging. Rate capability tests revealed that the specific capacities with higher slurry pH values were increased at C-rates above C/5. Cells with laser structured thick-film electrodes showed an increase in capacity by 40 mAh/g in comparison to cells with unstructured electrodes. Full article