Impact of Lithium-Ion Coordination on Lithium Electrodeposition

The lithium dendrite and parasitic reactions are two major challenges for lithium(Li)metal anode—the most promising anode materials for high-energy-density batteries.In this work,both the dendrite and parasitic reactions that occurred between the liquid electrolyte and Li-metal anode could be largely inhibited by regulating the Li+-solvation structure.The saturated Li+-solvation species exist in commonly used LiPF 6 liquid electrolyte that needs extra energy to desolvation during Li-electrodeposition.Partial solvation induced high-energy state Li-ions would be more energy favorable during the electron-reduction process,dominating the competition with solvent reduction reactions.The Li-symmetric cells that are cycling at higher temperatures show better performance;the cycled lithium metal anode with metallic lustre and the dendrite-free surface is observed.Theoretical calculation and experimental measurements reveal the existence of high-energy state Li+-solvates species,and their concentration increases with temperature.This study provides insight into the Li+-solvation structure and its electrodeposition characteristics.

SlZF3 regulates tomato plant height by directly repressing SlGA20ox4 in the gibberellic acid biosynthesis pathway

Plant height is an important target trait for crop genetic improvement.Our previous work has identified a salt-tolerant C2H2 zinc finger,SlZF3,and its overexpression lines also showed a semi-dwarf phenotype,but themolecular mechanism remains to be elucidated.Here,we characterized the dwarf phenotype in detail.The dwarfism is caused by a decrease in stem internode cell elongation and deficiency of bioactive gibberellic acids(GAs),and can be rescued by exogenous GA3 treatment.Gene expression assays detected reduced expression of genes in the GA biosynthesis pathway of the overexpression lines,including SlGA20ox4.Several protein-DNA interaction methods confirmed that SlZF3 can directly bind to the SlGA20ox4 promoter and inhibit its expression,and the interaction can also occur for SlKS and SlKO.Overexpression of SlGA20ox4 in the SlZF3-overexpressing line can recover the dwarf phenotype.Therefore,SlZF3 regulates plant height by directly repressing genes in the tomato GA biosynthesis pathway.

CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

The gas-solid reaction process with wide particle size distribution is extensively used in the chemical engineering field,especially the particle reacts with the gas gradually,such as fluorination reactions in fluidized beds.When the computational fluid dynamics-discrete element method(CFD-DEM)is used for the coupling simulation of multiphase and polydisperse particle reaction system,the grid size directly affects the accuracy of flow field information and simulation of chemical reaction.Furthermore,particle calculation time step will directly affect the efficiency of coupling calculation.In this work,a local grid and time step refinement method is proposed to simulate multiphase and polydisperse particle fluid-ization reaction system.In this method,the refined DEM grids are automatically generated in the computational domain around the fine particles,and the detailed fluid phase information is obtained with the interpolation algorithm.In the two-phase coupling process,particles are divided into different groups based on physical properties,each group has its own independent time step.The multistage conical-cylindrical spouted bed is proposed for the fluorination reaction process;the operating gas ve-locity range of the polydisperse particle system is extended by the new design while the particle size distribution changes with the gas-solid reaction process.It is demonstrated that the local grid and time step refinement method can improve the accuracy and efficiency of the traditional CFD-DEM method in the reaction process simulation,which describes a polydisperse particle system with wide particle size distribution.Aimed at improving the simulation accuracy and efficiency,this paper will be helpful for simulating the particle reaction process in the gas-solid fluidized bed and beneficial for the development of the CFD-DEM method.

Numerical simulation of uranium tetrafluoride fluorination in a multistage spouted bed using the improved CFD-DEM chemical reaction model

A CFD-DEM reaction coupling model was established to simulate UF_(4) fluorination process,in which heat and mass transfer,heterogeneous chemical reaction,and particle shrinkage model were considered.The gas behavior was described by the conservation laws of mass,momentum,and energy.The solid phase is modeled with the discrete element method,considering the gas-solid interphase force,contact force,heat transfer,and chemical reaction models based on the discretized surface.Each particle can be individually tracked and associated with specific physical properties.The proposed CFD-DEM reaction coupling model based on particle shrinking reaction model with discretized surface was validated by the experimental and literature results at first.Then a multistage conical spouted bed was proposed and the process of UF_(4) fluoridation reaction in it was investigated.The fluidization characteristics and the con-centration distribution of gaseous products in the spouted bed with an extended gas velocity range were obtained and analyzed.In addition,the effects of different parameters,such as superficial gas velocity,temperature,fluorine concentration,on fluoridation rate and the fluorine conversion rate were inves-tigated based on the proposed CFD-DEM reaction coupling model.The results obtained in this work are beneficial for method development of the chemical reaction simulation research in particle scale using the CFD-DEM model,and useful for operation and equipment parameters design of the uranium tetra-fluoride fluorinate industrial process in the future.

CFD–DEM–CVD multi-physical field coupling model for simulating particle coating process in spout bed

Particle coating is a very important step in many industrial production processes as the particle coating layers may fix surfaces with unique advantages. Given the limitation and disadvantages of the existing simulation methods, a coupled CFD–DEM–CVD multi-physical field model for particle-coating simulations has been established taking into account the velocity field, temperature field, concentration field, and deposition model. In this model, gas behavior and chemical reactions are simulated in the CFD frame based on the conservation laws of mass, momentum, and energy. The particle behavior is simulated in the DEM frame based on the gas–solid interphase force model and contact force model. The deposition behavior is simulated in the CVD frame based on the particle movement–adhesion–deposition model. The coupled model can be implemented in Fluent-EDEM software with their user definition function and application programming interface. The particle coating process involving the pyrolysis of acetylene was investigated, and the effect of bed temperature and inlet gas velocity on deposition rate and coating efficiency were investigated based on the proposed model with adjustable deposition coefficients. Both the average deposition layer mass and the average deposition layer thickness were found to be proportional to the elapsed time and increased at the rate of about 1.05 × 10^-2 mg/s and 3.45 × 10^-4 mm/s, respectively, setting the inlet gas velocity to 11 m/s and bed temperature to 1680 K. A higher temperature and larger inlet gas velocity lead to a larger deposition rate, but the coating efficiency decreases because of limits imposed by the chemical reaction. At a bed temperature of 1280 K, the average deposition rate is 7.40 × 10?3 mg/s when the inlet gas velocity is set to 11 m/s, which is about double the deposition rate when the inlet gas velocity is set as 5 m/s. The proposed model can provide some guidance for the operating conditions and parameters design of the spouted bed in actual coating settings and can also be further developed as a basic model of mechanisms to integrate detailed information across multiple scales.

CFD-DEM-VDGM method for simulation of particle fluidization behavior in multi-ring inclined-hole spouted fluidized bed

The simulation of particle fluidization behavior in a complex geometry with a large number of particles is challenging owing to the complexity of unstructured computational grids and high computational intensity.In this study,a virtual dual-grid model(VDGM)is proposed to calculate the solid volume fraction in unstructured grids and speed up the calculation.The VDGM is coupled with a computational fluid dynamics-discrete element method model to simulate particle fluidization behavior in a multi-ring inclined-hole spouted fluidized bed with 4.2 million particles under a high temperature of 1423 K.A computational fluid dynamics-discrete element method-virtual dual-grid model(CFD-DEM-VDGM)coupling model is implemented based on commercial software Fluent and EDEM.The time step settings in Fluent and EDEM and the pattern of particle data transfer in Fluent are improved to speed up the calculation.It is discovered that the VDGM can calculate the solid volume fraction in unstructured grids of complex geometry and speed up the calculation effectively.The calculation speed increased by more than 10 times compared with that of the segmentation sampling method.The new pattern of particle data transfer in Fluent can reduce data transfer time by more than 90%.The fluidization behavior of 4.2 million high-density particles in the multi-ring inclined-hole spouted fluidized bed is obtained and analyzed in detail.The CFD-DEM-VDGM coupling method is validated for the bed expansion height and spouting cycle time in a spouted fluidized bed via experimental results.