The structural design of electrodes plays a crucial role in enhancing the performance and safety of lithium-ion batteries. In this study, an electrochemical-thermal coupling model is developed to investigate the effect of gradient porous electrode structures at the separator-positive interface on battery behavior. By incorporating spatial variations in electrode porosity together with gradient interface distributions of active particles, the developed model enables a comprehensive characterization of the coupled evolution of electrochemical reactions, heat generation, and temperature fields within the battery. The results demonstrate that a higher consistency in the specific surface area distribution of active particles at the separator-positive interface leads to more uniform ion diffusion. This structural configuration also contributes to a more stable current density distribution under different discharge rates, while minimizing the temperature gradient at the separator. Furthermore, it is found that a uniform gradient electrode with a porosity of 0.25 exhibits superior battery stability. This work provides theoretical insights into the rational design of gradient electrode architectures and offers practical guidance for the development of high-performance lithium-ion batteries.
 

Electrochemical-thermal coupling, uniform gradient electrode, separator-positive interface, temperature gradient