A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of elec...A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of electrode particles are considered. The influence of BV reaction kinetics and concentration-dependent exchange current density(ECD) on concentration profile and DIS evolution are numerically investigated. BV reaction kinetics leads to a decrease in Li-ion concentration and DIS. In addition, concentrationdependent ECD results in a decrease in Li-ion concentration and an increase in DIS. Size polydispersity of electrode particles significantly affects the concentration profile and DIS.Optimal macroscopic state of charge(SOC) should consider the influence of the microscopic SOC values and mass fractions of differently sized particles.展开更多
An earlier study manipulated the Butler-Volmer equation to effectively model a lithium-ion capacitor’s (LIC) energy storage as a function of its constituent components and charge current. However, this model had seve...An earlier study manipulated the Butler-Volmer equation to effectively model a lithium-ion capacitor’s (LIC) energy storage as a function of its constituent components and charge current. However, this model had several shortcomings: computed temperature values were too low, voltage was inaccurate, and the model required Warburg impedance values that were two orders of magnitude higher than experimental results. This study began by analyzing the model’s temperature and voltage computations in order to justify output values. Ultimately, these justifications failed. Therefore, in situ temperature rise was measured during charge cycles. Experimental results indicated that temperature increases minimally during a charge cycle (<1%). At high current densities (≥150 A<span style="white-space:nowrap;">·</span>kg<sup>-1</sup>) temperature increase is negligible. After it was found that LIC temperature change is minimal during a charge cycle, the model accurately computed LIC voltage during the charge cycle and computed Warburg impedance that agreed with values derived from earlier experimental studies, even falling within the measurements’ precision error.展开更多
Dynamic model of the logistic growth in ecology is applied in the ecotourism development of Jiuzhaigou and Huanglong.Point management countermeasures of environmental capacity in ecotourism region are put forward.
基于熔体组元离子半径和Butler方程,建立RE2O3-MgO-SiO2(RE=La,Nd,Sm,Gd和Y)熔体表面张力热力学计算模型。本模型利用纯组元的表面张力和摩尔体积以及熔体中各组元阳离子和阴离子半径可以获得E2O3-MgO-SiO2熔体表面张力随熔渣成分和温...基于熔体组元离子半径和Butler方程,建立RE2O3-MgO-SiO2(RE=La,Nd,Sm,Gd和Y)熔体表面张力热力学计算模型。本模型利用纯组元的表面张力和摩尔体积以及熔体中各组元阳离子和阴离子半径可以获得E2O3-MgO-SiO2熔体表面张力随熔渣成分和温度的变化规律。计算1873 K La2O3-MgO-SiO2熔体等表面张力线并研究熔体成分对表面张力的影响。1873 K的纯组元La2O3,Gd2O3,Nd2O3和Y2O3的表面张力通过本模型计算分别为686、677、664和541 m N/m。除了Y2O3外,纯稀土氧化物的表面张力随其阳离子磁场强度增加而呈线性减小,而Y2O3的表面张力相对减小更多。表面张力的计算结果与文献数据一致,1873 K本模型平均偏差为1.05%。展开更多
基金financial support by the National Natural Science Foundation of China (Grants 11472165, 11332005)
文摘A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion(Liion) diffusion, diffusion-induced stress(DIS), Butler–Volmer(BV) reaction kinetics, and size polydispersity of electrode particles are considered. The influence of BV reaction kinetics and concentration-dependent exchange current density(ECD) on concentration profile and DIS evolution are numerically investigated. BV reaction kinetics leads to a decrease in Li-ion concentration and DIS. In addition, concentrationdependent ECD results in a decrease in Li-ion concentration and an increase in DIS. Size polydispersity of electrode particles significantly affects the concentration profile and DIS.Optimal macroscopic state of charge(SOC) should consider the influence of the microscopic SOC values and mass fractions of differently sized particles.
文摘An earlier study manipulated the Butler-Volmer equation to effectively model a lithium-ion capacitor’s (LIC) energy storage as a function of its constituent components and charge current. However, this model had several shortcomings: computed temperature values were too low, voltage was inaccurate, and the model required Warburg impedance values that were two orders of magnitude higher than experimental results. This study began by analyzing the model’s temperature and voltage computations in order to justify output values. Ultimately, these justifications failed. Therefore, in situ temperature rise was measured during charge cycles. Experimental results indicated that temperature increases minimally during a charge cycle (<1%). At high current densities (≥150 A<span style="white-space:nowrap;">·</span>kg<sup>-1</sup>) temperature increase is negligible. After it was found that LIC temperature change is minimal during a charge cycle, the model accurately computed LIC voltage during the charge cycle and computed Warburg impedance that agreed with values derived from earlier experimental studies, even falling within the measurements’ precision error.
文摘Dynamic model of the logistic growth in ecology is applied in the ecotourism development of Jiuzhaigou and Huanglong.Point management countermeasures of environmental capacity in ecotourism region are put forward.
基金Project(51374020)supported by the National Natural Science Foundation of China
文摘基于熔体组元离子半径和Butler方程,建立RE2O3-MgO-SiO2(RE=La,Nd,Sm,Gd和Y)熔体表面张力热力学计算模型。本模型利用纯组元的表面张力和摩尔体积以及熔体中各组元阳离子和阴离子半径可以获得E2O3-MgO-SiO2熔体表面张力随熔渣成分和温度的变化规律。计算1873 K La2O3-MgO-SiO2熔体等表面张力线并研究熔体成分对表面张力的影响。1873 K的纯组元La2O3,Gd2O3,Nd2O3和Y2O3的表面张力通过本模型计算分别为686、677、664和541 m N/m。除了Y2O3外,纯稀土氧化物的表面张力随其阳离子磁场强度增加而呈线性减小,而Y2O3的表面张力相对减小更多。表面张力的计算结果与文献数据一致,1873 K本模型平均偏差为1.05%。
