CN112966414B - Finite element analysis method for influencing deposition current and potential distribution on lithium metal surface by dielectric effect - Google Patents

Finite element analysis method for influencing deposition current and potential distribution on lithium metal surface by dielectric effect Download PDF

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CN112966414B
CN112966414B CN202110217142.3A CN202110217142A CN112966414B CN 112966414 B CN112966414 B CN 112966414B CN 202110217142 A CN202110217142 A CN 202110217142A CN 112966414 B CN112966414 B CN 112966414B
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CN112966414A (en
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张耀辉
何一涛
王志红
吕喆
黄喜强
刘志国
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Harbin Institute of Technology
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Abstract

A finite element analysis method for influencing the distribution of deposition current and potential on the surface of lithium metal by dielectric effect aims to solve the problem that the deposition current and potential in the existing lithium metal protective film are influenced by dielectric properties. The finite element analysis method comprises the following steps: firstly, establishing a solid two-dimensional model; setting electrical parameters of lithium metal, a protective film and electrolyte in the two-dimensional model, and performing mesh generation on the input entity two-dimensional model; thirdly, researching the ion motion law by selecting a Nernst-Plank equation; fourthly, selecting an electroanalysis module to simulate an electrodeposition process; fifthly, selecting a solid mechanics and static electricity module to simulate dielectric behavior; sixthly, simulating the diffusion of the double electric layers on the surfaces of the electrodes; establishing space charge density coupling; eighthly, setting boundary conditions of an electric analysis field; ninthly, setting a solver; and step ten, acquiring the surface potential distribution and the deposition current distribution of the lithium metal under the dielectric effect. The invention can carry out visual quantitative analysis on the lithium ion deposition current and the surface potential distribution on the surface of the lithium metal.

Description

Finite element analysis method for influencing deposition current and potential distribution on lithium metal surface by dielectric effect
Technical Field
The invention belongs to the field of lithium metal electrode protection materials, and particularly relates to a finite element analysis method for influencing the deposition current and potential distribution on the surface of lithium metal based on a dielectric effect.
Background
The development of energy storage materials is an inherent driving force for the advancement of modern technology. In the fields of electric vehicles, energy storage and current hot robots, energy storage technology plays a very important role. The energy density, volume and morphology of the battery directly determine the range of applications of the power supply system. For example, lithium ion batteries with high energy density are becoming increasingly thinner for mobile phones and notebooks. However, the theoretical capacity of the graphite anode used by the traditional lithium ion battery is smaller and is only 372mAh/g, which limits the further improvement of the battery capacity. Lithium metal anodes have a high theoretical capacity of 3860mAh/g, which makes them well suited for use in lithium ion batteries and has been considered as ideal anodes in lithium battery systems over the last 40 years. However, the formation of dendrites on lithium metal poses safety problems due to the possibility of short circuits and explosions. Mainly hampering the widespread practical use of long-term lithium metal batteries. Therefore, it is necessary to develop a highly effective protection technique for suppressing dendrites. To date, a number of surface modification methods have been developed. Among them, the artificial protective film has attracted people's attention due to its special protective effect and high practical value. The mechanism of action of the protective film for inhibiting dendrite is generally explained as that the protective film has high lithium ion conductivity, but neglects the fact that the protective film is mostly made of dielectric material and has dielectric properties. The finder of the SEI film Peled teaches that the SEI film is regarded as a dielectric thin film when its thickness is calculated. However, researchers have studied the characteristics of lithium metal surface protective films from a dielectric point of view very rarely.
Disclosure of Invention
The invention aims to solve the problem that the existing research on how the deposition current and the potential in the lithium metal protective film are influenced by dielectric properties is lacked, and therefore, the invention provides a finite element analysis method for influencing the deposition current and the potential distribution on the surface of lithium metal by the dielectric effect.
The finite element analysis method for influencing the deposition current and potential distribution on the surface of lithium metal by the dielectric effect is realized according to the following steps:
step one, establishing an entity two-dimensional model in COMSOL software according to the thickness of an actual protective film, wherein the entity two-dimensional model comprises lithium metal, the protective film and electrolyte;
setting electrical parameters of lithium metal, a protective film and electrolyte in the two-dimensional model, wherein the electrical parameters comprise conductivity and dielectric constant, performing mesh generation on the input entity two-dimensional model, selecting mesh types and setting mesh sizes;
selecting a current distribution module for three times in COMSOL software, and selecting a Nernst-Plank equation to study the ion motion law, wherein the Nernst-Plank equation is as follows:
Figure BDA0002954245720000021
wherein c isiConcentration of i ion (mol/m)3)，ziChemical valence, Di-diffusion coefficient (m)2/s)，um,iMobility (s. mol/kg), F-Faraday constant (C/mol), φlElectrolyte potential, Ji-molar flux associated with convective mass transfer;
selecting an electric analysis module in COMSOL software to simulate an electrodeposition process, inputting the density and molar mass of lithium metal, setting an electrode surface on an interface between the lithium metal and a protective film in a two-dimensional model, and setting a dissolution deposition reaction:
Li++e-→Li；
the electrode kinetics expression type is selected as concentration-dependent kinetics and the local current density is set according to the following equation:
Figure BDA0002954245720000022
wherein i0，mExchange current density, cR，mConcentration of reducing substances (elemental lithium metal zero), C0，m-oxidizing substances (Li)+) Concentration of，ηmOverpotential, iloc,m-current density, T-temperature, of the electrode reaction;
and step five, selecting a solid mechanics and static module to simulate dielectric behavior, wherein the electric field intensity is a negative gradient of the electric potential in a static state:
Figure BDA0002954245720000023
and combining the relation of the electric displacement D and the electric field E: d ═ epsilon0E+P；
Gauss' Law is:
Figure BDA0002954245720000024
in the formula, epsilon0Vacuum dielectric constant (F/m), P-electric polarization vector (C/m)2) Rho-space charge density (C/m)3) Obtaining the charge distribution caused by dielectric polarization in the protective film through Gauss law;
selecting a dilute substance transfer module to simulate an electrode surface diffusion double electric layer;
step seven, space charge density coupling is established, the electric double layer capacitance on the surface of the electrode is described by using a GCS (Gouy-Chapman-Stern) model, the interface capacitance is a plate capacitance, and the distance between the electrodes is the sum of the size of the Stern layer and the length of Debye;
step eight, setting boundary conditions of an electric analysis field, and setting a constant current mode and a constant voltage mode;
step nine, solver setting, and adding full coupling;
step ten, acquiring the potential distribution and the deposition current distribution of the surface of the lithium metal under the dielectric effect through a solver, and completing finite element analysis of the deposition current and the potential distribution of the surface of the lithium metal under the dielectric effect.
According to the invention, the current uniformity when the dielectric effect exists and the dielectric effect does not exist in the lithium metal surface protective film is drawn and compared, the influence degree of the dielectric effect on the current uniformity is evaluated, and the influence degree is compared with the experimental result, so that the correctness of the simulation result is verified, and the experimental test method can be replaced.
The finite element analysis method for influencing the deposition current and the potential distribution on the surface of the lithium metal by the dielectric effect can solve the problem of visual quantitative analysis of the deposition current and the surface potential distribution of the lithium ions on the surface of the lithium metal under the protection of the dielectric film, obtain the dielectric constant range of the protective film with the best protection effect by comparing the concentration distribution uniformity of the lithium ions on the surface of the lithium metal, and provide an important theoretical basis for the design of the protective film material.
According to the invention, the current uniformity when the dielectric effect exists and the dielectric effect does not exist in the lithium metal surface protective film is drawn and compared, the influence degree of the dielectric effect on the current uniformity is evaluated, and the influence degree is compared with the experimental result, so that the correctness of the simulation result is verified, and the experimental test method can be replaced.
The finite element analysis method for influencing the deposition current and the potential distribution on the surface of the lithium metal by the dielectric effect can solve the problem of visual quantitative analysis of the deposition current and the surface potential distribution of the lithium ions on the surface of the lithium metal under the protection of the dielectric film, obtain the dielectric constant range of the protective film with the best protection effect by comparing the concentration distribution uniformity of the lithium ions on the surface of the lithium metal, and provide an important theoretical basis for the design of the protective film material.
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FIG. 1 is a schematic flow chart of a finite element analysis method of the present invention for dielectric effect influence on the deposition current and potential distribution on the surface of lithium metal;
FIG. 2 is a schematic diagram of a structure for building a two-dimensional model of an entity according to the present invention;
FIG. 3 is a graph showing the dielectric polarization curves at different deposition times in the lithium metal surface protective film described in the examples, wherein 1 to 0s, 2 to 100s, 3 to 2000s, and 4 to 5000 s;
FIG. 4 is a graph showing the distribution of lithium ion concentration on the surface of lithium metal under the protection of protective films with different dielectric constants in the examples;
FIG. 5 is a graph of the surface current distribution of lithium metal under the protection of protective films with different dielectric constants in the examples, wherein 1 represents the protection film with no dielectric effect, and 2 represents the protection film with dielectric effect;
FIG. 6 shows PVDF-HFP/Al in the examples2O3Overpotential stability test chart of lithium metal symmetrical battery covered by protective film, wherein1 represents PVDF-HFP/Al2O3(10 wt%) 2 represents PVDF-HFP/Al2O3(5 wt%) 3 represents PVDF-HFP/Al2O3(1wt％)；
FIG. 7 is PVDF-HFP/Co in example3O4Overpotential stability test chart of lithium metal symmetrical battery covered by protective film, wherein 1 represents PVDF-HFP/Co3O4(10 wt%) 2 represents PVDF-HFP/Co3O4(5 wt%), 3 represents PVDF-HFP/Co3O4(1wt％)；
FIG. 8 shows PVDF-HFP/TiO in the examples2Overpotential stability test chart of lithium metal symmetrical battery covered by protective film, wherein 1 represents PVDF-HFP/TiO2(1 wt%) 2 represents PVDF-HFP/TiO2(5% by weight), 3 represents PVDF-HFP/TiO2(10wt％)。
Detailed Description
The first embodiment is as follows: the finite element analysis method for influencing the deposition current and the potential distribution on the surface of the lithium metal by the dielectric effect is implemented according to the following steps:
step one, establishing an entity two-dimensional model in COMSOL software according to the thickness of an actual protective film, wherein the entity two-dimensional model comprises lithium metal, the protective film and electrolyte;
setting electrical parameters of lithium metal, a protective film and electrolyte in the two-dimensional model, wherein the electrical parameters comprise conductivity and dielectric constant, performing mesh generation on the input entity two-dimensional model, selecting mesh types and setting mesh sizes;
selecting a current distribution module for three times in COMSOL software, and selecting a Nernst-Plank equation to study the ion motion law, wherein the Nernst-Plank equation is as follows:
Figure BDA0002954245720000041
wherein c isiConcentration of i ion (mol/m)3)，ziChemical valence of Di-diffusion coefficient (m)2/s)，um,iMobility (s. mol/kg), F-methodRatth constant (C/mol), philElectrolyte potential, Ji-molar flux associated with convective mass transfer;
selecting an electric analysis module in COMSOL software to simulate an electrodeposition process, inputting the density and molar mass of lithium metal, setting an electrode surface on an interface between the lithium metal and a protective film in a two-dimensional model, and setting a dissolution deposition reaction:
Li++e-→Li；
the electrode kinetics expression type is selected as concentration-dependent kinetics and the local current density is set according to the following equation:
Figure BDA0002954245720000042
wherein i0，mExchange current density, cR，mConcentration of reducing species (zero elemental lithium), c0，m-oxidizing substances (Li)+) Concentration, etamOverpotential, iloc,m-current density, T-temperature, of the electrode reaction;
and step five, selecting a solid mechanics and static module to simulate dielectric behavior, wherein the electric field intensity is a negative gradient of the electric potential in a static state:
Figure BDA0002954245720000043
and combining the relation of the electric displacement D and the electric field E: d ═ epsilon0E+P；
Gauss's law is:
Figure BDA0002954245720000044
in the formula, epsilon0Vacuum dielectric constant (F/m), P-electric polarization vector (C/m)2) Rho-space charge density (C/m)3) Obtaining the charge distribution caused by dielectric polarization in the protective film through Gauss law;
selecting a dilute substance transfer module to simulate an electrode surface diffusion double electric layer;
step seven, space charge density coupling is established, the electric double layer capacitance on the surface of the electrode is described by using a GCS (Gouy-Chapman-Stern) model, the interface capacitance is a plate capacitance, and the distance between the electrodes is the sum of the size of the Stern layer and the length of Debye;
step eight, setting boundary conditions of an electric analysis field, and setting a constant current mode and a constant voltage mode;
step nine, solver setting, and adding full coupling;
step ten, acquiring the potential distribution and the deposition current distribution of the surface of the lithium metal under the dielectric effect through a solver, and completing finite element analysis of the deposition current and the potential distribution of the surface of the lithium metal under the dielectric effect.
In the embodiment, the surface protective film with dielectric property is introduced into an electrochemical system for lithium metal deposition by using a finite element analysis method, so that a series of influences of dielectric effect on deposition current and surface potential distribution are obtained, and a theoretical basis is provided for material design of the lithium metal protective film.
The second embodiment is as follows: the difference between the present embodiment and the first embodiment is that the thickness of the passivation layer is set to 0.1 to 0.5 μm in the first step.
The third concrete implementation mode: the difference between the first and second embodiments is that in the second step, mesh subdivision is performed on the input entity two-dimensional model, the maximum unit size of the mesh is 0.01-0.5 micron, and the minimum unit size is 1 × 10-5～5×10-3And (5) micron.
The fourth concrete implementation mode is as follows: the difference between this embodiment and the first to third embodiments is that in step eight, the constant current mode is the total current, and the constant voltage mode sets the external potential.
The fifth concrete implementation mode: the fourth difference between the present embodiment and the specific embodiment is that a constant current mode is adopted, and the lithium metal surface potential distribution under the dielectric effect is obtained through a solver.
The sixth specific implementation mode: the fourth difference between this embodiment and the specific embodiment is that a constant voltage mode is adopted, and a solver is used to obtain the distribution of the deposition current on the surface of the lithium metal under the dielectric effect.
The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is that the transient solver is used as the solver in step nine.
The specific implementation mode is eight: the present embodiment is different from the first to seventh embodiments in that the graphs of the polarization intensity in the dielectric protective film for different deposition times are plotted in step ten.
Example (b): the finite element analysis method for influencing the deposition current and potential distribution on the surface of lithium metal by the dielectric effect is implemented according to the following steps:
step one, setting the thickness of a protective film to be 0.2 microns, establishing a solid two-dimensional model (shown in figure 2) in COMSOL 5.4 software of multi-physics coupling software, wherein the solid two-dimensional model comprises lithium metal, the protective film and electrolyte, ensuring that the proportion of the thickness of the protective film on the surface of the lithium metal in a picture can completely display a visual current distribution diagram, and adjusting a size unit;
setting electrical parameters of lithium metal, a protective film and electrolyte in the two-dimensional model, wherein the electrical parameters comprise conductivity and dielectric constant, performing mesh subdivision on the input entity two-dimensional model, and adopting a mesh with the maximum unit size of 0.1 micrometer and the minimum unit size of 3 multiplied by 10-4Micron, complete grid contains 388 domain elements and 59 boundary elements;
and in the second step, the characteristic parameters of the materials are set as follows:
Figure BDA0002954245720000051
Figure BDA0002954245720000061
selecting a current distribution module for three times in COMSOL 5.4 software, and selecting a Nernst-tank equation to study the ion motion law, wherein the Nernst-tank equation is as follows:
Figure BDA0002954245720000062
wherein c isiConcentration of i ion (mol)/m3)，ziChemical valence of Di-diffusion coefficient (m)2/s)，um,iMobility (s. mol/kg), F-Faraday constant (C/mol), φlElectrolyte potential, Ji-molar flux associated with convective mass transfer;
selecting an electric analysis module in COMSOL 5.4 software to simulate an electrodeposition process, inputting the density and molar mass of lithium metal, setting an electrode surface on an interface between the lithium metal and a protective film in a two-dimensional model, and setting a dissolution deposition reaction:
Li++e-→Li；
the electrode kinetics expression type is selected as concentration-dependent kinetics and the local current density is set according to the following equation:
Figure BDA0002954245720000063
wherein i0，mExchange current density, cR，mConcentration of reducing species (zero elemental lithium), c0，m-oxidizing substances (Li)+) Concentration, ηmOverpotential, iloc,m-current density, T-temperature, of the electrode reaction;
and step five, selecting a solid mechanics and static module to simulate dielectric behavior, wherein the electric field intensity is a negative gradient of the electric potential in a static state:
Figure BDA0002954245720000064
and combining the relation of the electric displacement D and the electric field E: d ═ epsilon0E+P；
Gauss' Law is:
Figure BDA0002954245720000065
in the formula, epsilon0Vacuum dielectric constant (F/m), P-electric polarization vector (C/m)2) Rho-space charge density (C/m)3) Obtaining the dielectric polarization strength of the electrode and the charge distribution caused by dielectric polarization in the protective film through Gauss law, and further analyzing the dielectric polarization charge to lithium depositionThe effects of current and potential distribution;
selecting a dilute substance transfer module to simulate an electrode surface diffusion double electric layer;
step seven, space charge density coupling is established, the electric double layer capacitance on the surface of the electrode is described by using a GCS (Gouy-Chapman-Stern) model, the interface capacitance is a plate capacitance, and the distance between the electrodes is the sum of the size of a Stern layer (namely an inner Helmholtz layer and an outer Helmholtz layer) and the length of Debye;
step eight, setting boundary conditions (namely the magnitude of a total current value) of an electric analysis field, wherein the constant current mode is the total current, and the constant voltage mode is used for setting an external potential;
step nine, solver setting, namely adding full coupling by adopting a transient solver;
step ten, drawing a polarization intensity curve graph (shown in fig. 3) in the dielectric protective film at different deposition time, judging the direction relation between the dielectric polarization intensity curve graph and an external electric field from the positive and negative relation of the dielectric polarization intensity curve graph and in the deposition process, reversing the direction of the dielectric polarization electric field and the external electric field, then obtaining the surface potential distribution and the deposition current distribution of the lithium metal under the dielectric effect in a constant current mode and a constant voltage mode respectively, and completing the finite element analysis of the surface deposition current and the potential distribution of the lithium metal under the dielectric effect.
In the embodiment, by comparing the distribution uniformity of lithium ion concentration on the surface of lithium metal, a proper range value of the relative dielectric constant is given, as shown in fig. 4, the proper range of the relative dielectric constant of the protective film material is 5-13.
In this embodiment, the current uniformity when the dielectric effect exists and the dielectric effect does not exist in the lithium metal surface protective film is plotted and compared, and the influence degree of the dielectric effect on the current uniformity is evaluated, as shown in fig. 5, when the dielectric effect exists in the protective film (PVDF-HFP), the surface current distribution is more uniform. And compared with the experimental results of the lithium symmetrical battery adopting the protective film with different relative dielectric constants, as shown in fig. 6, 7 and 8, the protective film material in fig. 6 is PVDF-HFP/Al2O3，PVDF-HFP/Al2O3(1 wt%) has a relative dielectric constant of 12.95, PVDF-HFP/Al2O3(5 wt.%) ofRelative dielectric constant of 13.15, PVDF-HFP/Al2O3(10 wt%) had a relative dielectric constant of 16.84. In FIG. 7, the protective film material is PVDF-HFP/Co3O4，PVDF-HFP/Co3O4(1 wt%) relative dielectric constant of 13.89, PVDF-HFP/Co3O4(5 wt%) has a relative dielectric constant of 25.70, PVDF-HFP/Co3O4(10 wt%) has a relative dielectric constant of 142.40. In FIG. 8, the protective film material is PVDF-HFP/TiO2，PVDF-HFP/TiO2(1 wt%) relative dielectric constant of 10.13, PVDF-HFP/TiO2(5 wt%) relative dielectric constant of 12.26, PVDF-HFP/TiO2(10 wt%) had a relative dielectric constant of 14.96. The relative dielectric constant of PVDF-HFP was 9.79.
The relative dielectric constant of the protective film is controlled by adopting the addition amount of different inorganic oxides in the PVDF-HFP film, and the interference caused by oxide species is eliminated by adopting different inorganic oxides. The cycle life of the lithium-lithium symmetric battery and the overpotential stability of a constant-current charge-discharge curve are used for judging the protection effect of the protective film, the relative dielectric constant of the protective film with a good effect is within the prediction range of the simulation result, the correctness of the simulation result is verified, and the method can be used for replacing an experimental test.
The lithium metal deposition process simulation of the coupling dielectric effect obtains the optimal dielectric constant range capable of promoting the surface deposition current to be uniform by analyzing the dielectric constants of different protective films. Through the analysis of the finite element analysis model, the current and potential distribution of the lithium metal surface in the presence of the protective film are simultaneously influenced by the dielectric polarization field, the external electric field and the concentration polarization field. The invention is applied to the fields of preparation of lithium metal electrodes and selection and design of modified materials.

Claims (8)

1. A finite element analysis method for influencing the distribution of deposition current and potential on the surface of lithium metal by dielectric effect is characterized in that the finite element analysis method is realized according to the following steps:
step one, establishing an entity two-dimensional model in COMSOL software according to the thickness of an actual protective film, wherein the entity two-dimensional model comprises lithium metal, the protective film and electrolyte;
setting electrical parameters of lithium metal, a protective film and electrolyte in the two-dimensional model, wherein the electrical parameters comprise conductivity and dielectric constant, performing mesh generation on the input entity two-dimensional model, selecting mesh types and setting mesh sizes;
selecting a current distribution module for three times in COMSOL software, and selecting a Nernst-Plank equation to study the ion motion law, wherein the Nernst-Plank equation is as follows:
Figure FDA0003610135830000011
wherein c isiI concentration of ions mol/m3，ziChemical valence, DiCoefficient of diffusion m2/s，um,iMobility s.mol/kg, F-Faraday constant C/mol, ΦlElectrolyte potential, Ji-molar flux associated with convective mass transfer;
selecting an electric analysis module in COMSOL software to simulate an electrodeposition process, inputting the density and molar mass of lithium metal, setting an electrode surface on an interface between the lithium metal and a protective film in a two-dimensional model, and setting a dissolution deposition reaction:
Li++e-→Li；
the electrode kinetics expression type is selected as concentration-dependent kinetics and the local current density is set according to the following equation:
Figure FDA0003610135830000012
wherein i0，mExchange current density, CR，mConcentration of reducing substances, cO，mConcentration of oxidizing species, etamOverpotential, iloc,m-current density, T-temperature, of the electrode reaction;
selecting a solid mechanics and static module to simulate dielectric behavior, and under a static state,electric field strength is a negative gradient of electric potential:
Figure FDA0003610135830000013
and combining the relation of the electric displacement D and the electric field E: d ═ epsilon0E+P；
Gauss's law is:
Figure FDA0003610135830000014
in the formula, epsilon0Vacuum dielectric constant F/m, P-electric polarization vector C/m2Rho-space charge density C/m3Obtaining the charge distribution caused by dielectric polarization in the protective film through Gauss law;
selecting a dilute substance transfer module to simulate an electrode surface diffusion double electric layer;
step seven, space charge density coupling is established, the electric double layer capacitance on the surface of the electrode is described by using a GCS model, the interface capacitance is a plate capacitance, and the distance between the electrodes is the sum of the size of a Stern layer and the length of a Debye layer;
step eight, setting boundary conditions of an electric analysis field, and setting a constant current mode and a constant voltage mode;
step nine, solver setting, and adding full coupling;
step ten, acquiring the potential distribution and the deposition current distribution of the surface of the lithium metal under the dielectric effect through a solver, and completing finite element analysis of the deposition current and the potential distribution of the surface of the lithium metal under the dielectric effect.
2. A finite element analysis method of dielectric effect influence on deposition current and potential distribution on lithium metal surface according to claim 1, wherein in the first step, the thickness of the protective film is set to 0.1-0.5 μm.
3. A finite element analysis method for influencing the deposition current and potential distribution on the surface of lithium metal by dielectric effect according to claim 1, characterized in that in the second step, the mesh division is performed on the input solid two-dimensional model, and the maximum unit size of the mesh is 0.01-0.5 μm, and the minimum unit size is 1 x 10-5～5×10-3And (3) micron.
4. A finite element analysis method of dielectric effect influence on deposition current and potential distribution on lithium metal surface as claimed in claim 1, wherein in step eight constant current mode is total current and constant voltage mode is set external potential.
5. A finite element analysis method for influencing the deposition current and potential distribution on the surface of lithium metal by dielectric effect according to claim 4, characterized in that the potential distribution on the surface of lithium metal under dielectric effect is obtained by a solver in a constant current mode.
6. A finite element analysis method of dielectric effect influence on lithium metal surface deposition current and potential distribution according to claim 4, characterized in that the lithium metal surface deposition current distribution under dielectric effect is obtained by a solver using constant voltage mode.
7. A finite element analysis method of dielectric effect influencing the deposition current and potential distribution on the surface of lithium metal as claimed in claim 1, characterized in that in step nine the solver employs a transient solver.
8. The finite element analysis method of dielectric effect influencing deposition current and potential distribution on lithium metal surface according to claim 1, characterized in that in the step ten, plots of the polarization intensity in the dielectric protection film are plotted for different deposition times.
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