COMSOL simulation study on the effect of electrolyte concentration on ion transport in zinc-ion batteries
Wang, Yifu (2026)
Kandidaatintyö
2026
School of Energy Systems, Energiatekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2026051948581
https://urn.fi/URN:NBN:fi-fe2026051948581
Tiivistelmä
This paper establishes a simplified three-dimensional layered zinc-ion battery model using COMSOL Multiphysics to compare the ion transport and constant current discharge response under different ZnSO₄ electrolyte concentrations. The model consists of a Zn negative electrode, ZnSO₄ electrolyte, and MnO₂ positive electrode, and couples the dilute substance transfer module and the secondary current distribution module. Three working conditions of 1.0 M, 2.0 M, and 3.0 M ZnSO₄ were set, corresponding to initial Zn²⁺ concentrations of 1000, 2000, and 3000 mol m⁻³. The electrolyte conductivity and Zn²⁺ diffusion coefficient were set according to literature data and concentration-related transport trends.
The results show that under the same constant current density, discharge time and active material mass conditions, the specific capacity curves of the three working conditions are almost completely overlapping, and the battery terminal voltage and voltage-capacity curves also show only minor differences. This indicates that under the current simplified geometric structure and lower current density conditions, the macro discharge curve is not very sensitive to the change in electrolyte concentration. In contrast, the polarization voltage and Zn²⁺ concentration profiles can better reflect the transport differences at different concentrations. The 3.0 M working condition, due to the lower diffusion coefficient, formed a more obvious concentration gradient at the end of the discharge; the 2.0 M working condition showed a better compromise between ion supply, conductivity and diffusion ability.
In conclusion, the concentration of ZnSO₄ electrolyte is a coupled transmission variable that affects ion supply, conductivity, diffusion behavior, and polarization characteristics. The results of this study indicate that in the simplified COMSOL model, 2.0 M ZnSO₄ has a better transmission-polarization balance, which can provide a reference for the optimization of aqueous zinc-ion battery electrolytes and the development of more realistic models.
The results show that under the same constant current density, discharge time and active material mass conditions, the specific capacity curves of the three working conditions are almost completely overlapping, and the battery terminal voltage and voltage-capacity curves also show only minor differences. This indicates that under the current simplified geometric structure and lower current density conditions, the macro discharge curve is not very sensitive to the change in electrolyte concentration. In contrast, the polarization voltage and Zn²⁺ concentration profiles can better reflect the transport differences at different concentrations. The 3.0 M working condition, due to the lower diffusion coefficient, formed a more obvious concentration gradient at the end of the discharge; the 2.0 M working condition showed a better compromise between ion supply, conductivity and diffusion ability.
In conclusion, the concentration of ZnSO₄ electrolyte is a coupled transmission variable that affects ion supply, conductivity, diffusion behavior, and polarization characteristics. The results of this study indicate that in the simplified COMSOL model, 2.0 M ZnSO₄ has a better transmission-polarization balance, which can provide a reference for the optimization of aqueous zinc-ion battery electrolytes and the development of more realistic models.