The lithium-and manganese-rich layered oxide(LMR)holds great promise as a cathode material for lithiumion battery(LIB)applications due to its high capacity,high voltage and low cost.Unfortunately,its poor initial Coul...The lithium-and manganese-rich layered oxide(LMR)holds great promise as a cathode material for lithiumion battery(LIB)applications due to its high capacity,high voltage and low cost.Unfortunately,its poor initial Coulombic efficiency(ICE)and unstable electrode/electrolyte interface with continuous growth of the solid electrolyte interphase leads to high impedance and large overpotential.These effects cause severe capacity loss and safety issues.In this work,we have developed a novel approach to fabricate a stable LMR cathode with a uniform thin layer of aluminum oxide(Al2O3)coated on the surface of the LMR particles.This synthesis approach uses the microemulsion method that is environment-friendly,cost-effective and can be easily scaled.Typically,an 8-nm layer of Al2O3 is shown to be effective in stabilizing the electrode/electrolyte interface(enhanced ICE to82.0%and moderate impedance increase over 200 cycles).Moreover,the phase transformation from layered to spinel is inhibited(96.3%average voltage retention)and thermal stability of the structure is significantly increased(heat release reduced by 72.4%).This study opens up a new avenue to address interface issues in LIB cathodes and prompts the practical applications of high capacity and voltage materials for high energy density batteries.展开更多
Coating of particulate materials in fluidized beds is a widely used technique to eliminate particle agglomeration,provide slow release of an active substance,or protect active ingredients.When thin polymer shells are ...Coating of particulate materials in fluidized beds is a widely used technique to eliminate particle agglomeration,provide slow release of an active substance,or protect active ingredients.When thin polymer shells are applied on a particle surface,it is important to determine the process parameters that provide coating uniformity.In this study,the degree of coverage,defined as the fraction of the coated surface of the particles,is proposed as a quantitative criterion of coating uniformity.A new model for the batch fluidized-bed coating process is presented.The model allows prediction of the function of particle distribution according to the degree of coverage at a given process time and thereby enables assessment of coating uniformity.An algorithm for the numerical solution of model equations for a batch fluidized-bed coater is described.The influences of the main process parameters on the coating uniformity were shown.展开更多
The digital camouflage spraying of special vehicles carried out by robots can greatly improve the spraying efficiency, spraying quality, and rapid adaptability to personalized patterns. The selection of spray tool and...The digital camouflage spraying of special vehicles carried out by robots can greatly improve the spraying efficiency, spraying quality, and rapid adaptability to personalized patterns. The selection of spray tool and the accuracy of the adopted mathematical spray tool model has a great impact on the effectiveness of spray path planning and spraying quality. Since traditional conical spray tool models are not suitable for spraying rectangular digital camouflage, according to the characteristics of digital camouflage, the coating thickness cumulative distribution model of strip nozzle spray tool for 2 D plane spraying and 3 D surface spraying is derived, and its validity is verified by simulation. Based on the accumulation velocity model of the coating thickness(AVCT) on the curved surface and aiming at spraying path planning within the same surface and different surfaces, a path parameter optimization method based on coating uniformity evaluation of adjacent path overlapping area is proposed. Combined with the vehicle surface model, parameters such as path interval, spray tool angle and spray tool motion velocity can be calculated in real-time to ensure uniform coating. Based on the known local three-dimensional model of vehicle surface and the comprehensive spraying simulation, the validity of the purposed models: the coating thickness on the adjacent path area(CTAPA), the coating thickness on the intersection of two surfaces(CTITS), the coating thickness on the intersection of a plane and a surface(CTIPS), and the optimization method of path parameters are verified. The results show that compared with the traditional spray tool, the strip nozzle can better ensure the uniformity of the coating thickness of digital camouflage spray. Finally, according to a practical spraying experiment, the results prove that the proposed models not only are effective but also meet the practical industrial requirements and are of great practical value.展开更多
Controlled-release coated urea(CRCU)is an important agrochemical in precision farming,with its effectiveness reliant on the quality of the coating film and the nutrient-release kinetics.This study explores the use of ...Controlled-release coated urea(CRCU)is an important agrochemical in precision farming,with its effectiveness reliant on the quality of the coating film and the nutrient-release kinetics.This study explores the use of a chemically modified lignocellulosic biopolymer derived from almond shells as a coating material for producing CRCU using Wurster fluidized-bed equipment.The study examines how process parameters—namely fluidized-bed temperature(T_(fb)),spray rate(R_(spray)),fluidizing-air flow rate(Q_(air)),and atomizing-air pressure(P_(air))—influence coating quality and nutrient-release kinetics.These are assessed through the inter-particle coefficient of coating mass variance(CMV)and the diffusion coefficient,respectively.The mechanism of nutrient release was studied using the Ritger and Peppas empirical model,specifically by calculating the diffusional exponent,n,for all samples.A Response Surface Methodology(RSM)approach coupled with a CCRD was applied to plan the experiments,perform statistical analysis,predict outcomes,and optimize the process conditions.The Analysis of Variance indicated that Tfb significantly impacts the studied parameters.Optimal coating quality(CMV=6.7%)was achieved under conditions of T_(fb)=75℃,Q_(air)=80 m^(3)/h,R_(spray)=0.17 mL/s,and P_(air)=3.1 bar.The optimum diffusion coefficient(2.2×10^(-1)cm^(2)/s)was obtained at T_(fb)=78℃,Q_(air)=75 m^(3)/h,R_(spray)=0.125 mL/s,and P_(air)=3.2 bar.The experimental and predicted responses showed close agreement that validates the regression models for predicting quality of coating films and kinetics of nutrient-release.Based on the n values,some samples exhibited Fickian diffusion,while others followed a non-Fickian nutrient-release mechanism.展开更多
基金supported by the National Natural Science Foundation of China(U1564205)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality(IDHT20180508)。
文摘The lithium-and manganese-rich layered oxide(LMR)holds great promise as a cathode material for lithiumion battery(LIB)applications due to its high capacity,high voltage and low cost.Unfortunately,its poor initial Coulombic efficiency(ICE)and unstable electrode/electrolyte interface with continuous growth of the solid electrolyte interphase leads to high impedance and large overpotential.These effects cause severe capacity loss and safety issues.In this work,we have developed a novel approach to fabricate a stable LMR cathode with a uniform thin layer of aluminum oxide(Al2O3)coated on the surface of the LMR particles.This synthesis approach uses the microemulsion method that is environment-friendly,cost-effective and can be easily scaled.Typically,an 8-nm layer of Al2O3 is shown to be effective in stabilizing the electrode/electrolyte interface(enhanced ICE to82.0%and moderate impedance increase over 200 cycles).Moreover,the phase transformation from layered to spinel is inhibited(96.3%average voltage retention)and thermal stability of the structure is significantly increased(heat release reduced by 72.4%).This study opens up a new avenue to address interface issues in LIB cathodes and prompts the practical applications of high capacity and voltage materials for high energy density batteries.
基金supported by the Council on Grants of the President of the Russian Federation(Grant No.SP-1951.2021.1).
文摘Coating of particulate materials in fluidized beds is a widely used technique to eliminate particle agglomeration,provide slow release of an active substance,or protect active ingredients.When thin polymer shells are applied on a particle surface,it is important to determine the process parameters that provide coating uniformity.In this study,the degree of coverage,defined as the fraction of the coated surface of the particles,is proposed as a quantitative criterion of coating uniformity.A new model for the batch fluidized-bed coating process is presented.The model allows prediction of the function of particle distribution according to the degree of coverage at a given process time and thereby enables assessment of coating uniformity.An algorithm for the numerical solution of model equations for a batch fluidized-bed coater is described.The influences of the main process parameters on the coating uniformity were shown.
基金supported by Key Research and Development Program of China (No. 2018YFB1306303)。
文摘The digital camouflage spraying of special vehicles carried out by robots can greatly improve the spraying efficiency, spraying quality, and rapid adaptability to personalized patterns. The selection of spray tool and the accuracy of the adopted mathematical spray tool model has a great impact on the effectiveness of spray path planning and spraying quality. Since traditional conical spray tool models are not suitable for spraying rectangular digital camouflage, according to the characteristics of digital camouflage, the coating thickness cumulative distribution model of strip nozzle spray tool for 2 D plane spraying and 3 D surface spraying is derived, and its validity is verified by simulation. Based on the accumulation velocity model of the coating thickness(AVCT) on the curved surface and aiming at spraying path planning within the same surface and different surfaces, a path parameter optimization method based on coating uniformity evaluation of adjacent path overlapping area is proposed. Combined with the vehicle surface model, parameters such as path interval, spray tool angle and spray tool motion velocity can be calculated in real-time to ensure uniform coating. Based on the known local three-dimensional model of vehicle surface and the comprehensive spraying simulation, the validity of the purposed models: the coating thickness on the adjacent path area(CTAPA), the coating thickness on the intersection of two surfaces(CTITS), the coating thickness on the intersection of a plane and a surface(CTIPS), and the optimization method of path parameters are verified. The results show that compared with the traditional spray tool, the strip nozzle can better ensure the uniformity of the coating thickness of digital camouflage spray. Finally, according to a practical spraying experiment, the results prove that the proposed models not only are effective but also meet the practical industrial requirements and are of great practical value.
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(grant number IMSIU-DDRSP2502).
文摘Controlled-release coated urea(CRCU)is an important agrochemical in precision farming,with its effectiveness reliant on the quality of the coating film and the nutrient-release kinetics.This study explores the use of a chemically modified lignocellulosic biopolymer derived from almond shells as a coating material for producing CRCU using Wurster fluidized-bed equipment.The study examines how process parameters—namely fluidized-bed temperature(T_(fb)),spray rate(R_(spray)),fluidizing-air flow rate(Q_(air)),and atomizing-air pressure(P_(air))—influence coating quality and nutrient-release kinetics.These are assessed through the inter-particle coefficient of coating mass variance(CMV)and the diffusion coefficient,respectively.The mechanism of nutrient release was studied using the Ritger and Peppas empirical model,specifically by calculating the diffusional exponent,n,for all samples.A Response Surface Methodology(RSM)approach coupled with a CCRD was applied to plan the experiments,perform statistical analysis,predict outcomes,and optimize the process conditions.The Analysis of Variance indicated that Tfb significantly impacts the studied parameters.Optimal coating quality(CMV=6.7%)was achieved under conditions of T_(fb)=75℃,Q_(air)=80 m^(3)/h,R_(spray)=0.17 mL/s,and P_(air)=3.1 bar.The optimum diffusion coefficient(2.2×10^(-1)cm^(2)/s)was obtained at T_(fb)=78℃,Q_(air)=75 m^(3)/h,R_(spray)=0.125 mL/s,and P_(air)=3.2 bar.The experimental and predicted responses showed close agreement that validates the regression models for predicting quality of coating films and kinetics of nutrient-release.Based on the n values,some samples exhibited Fickian diffusion,while others followed a non-Fickian nutrient-release mechanism.
