COMSOL-Based Numerical Modeling of Zn<sup>2+</sup> Transport in Glass-State Composite Cathodes for Aqueous Zinc-Ion Batteries

Zhang, Lu; Qi, Xiaolei; Huang, Li; Fu, Baosen; He, Yunfei; Guo, Yanyan

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J. Electrochem. Sci. Technol > Accepted Articles

Research Article

DOI: https://doi.org/10.33961/jecst.2026.00346 [Accepted]
Published online August 3, 2026.

COMSOL-Based Numerical Modeling of Zn²⁺ Transport in Glass-State Composite Cathodes for Aqueous Zinc-Ion Batteries

Lu Zhang¹, Xiaolei Qi¹, Li Huang¹, Baosen Fu¹, Yunfei He², Yanyan Guo¹

¹School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China
²School of Optoelectronic Engineering, Changchun University of Science and Technology, Changchun 130022, China

Correspondence: Yanyan Guo,
Email: guoyanyan@cust.edu.cn

Received: 22 April 2026 • Accepted: 21 July 2026

Abstract

Aqueous zinc-ion batteries (AZIBs) are attractive for safe and low-cost stationary storage, but quantitative modeling of glass-state cathodes requires both physically consistent transport equations and independent rate validation. In this work, the original one-dimensional COMSOL framework for a ZFMP (ZnO–Fe₂O₃–MnO₂–P₂O₅) glass-state composite cathode was corrected by enforcing a capacity-conserving mapping between external specific capacity and the internal cathode filling state. The continuum model couples Zn²⁺ transport, charge conservation in the solid and electrolyte phases, and Butler–Volmer kinetics. A transparent power-law utilization factor was then added to represent the rate-dependent fraction of accessible active material without assigning the loss to an unverified microscopic mechanism. Three parallel cells at 50 mA g⁻¹ gave 178.02 ± 0.70 mAh g⁻¹; the corrected low-rate model reached 178.0 mAh g⁻¹ with a voltage RMSE of 26 mV. The utilization exponent k = 0.138 was identified only from the 0.5 C capacity of 164.38 ± 0.59 mAh g⁻¹. With no further fitting, the hybrid model predicted 149.36 mAh g⁻¹ at 1.0 C, compared with 149.97 ± 1.28 mAh g⁻¹ experimentally, corresponding to a capacity error of 0.41%. The frozen continuum component reproduced the correct rate-dependent voltage ordering but overestimated high-rate capacity, whereas the hybrid framework separates mechanistic voltage polarization from semi-empirical utilization loss. This experimentally constrained approach provides a more defensible basis for interpreting Zn²⁺ transport and rate capability in glass-state composite cathodes.

Keywords: aqueous zinc-ion battery, glass-state cathode, Zn²⁺ transport, COMSOL, hybrid model, rate-dependent utilization, experimental validation