Understanding the microstructure effects of graphite electrode in lithium-ion batteries through multi-physics simulation

Abstract

Graphite anodes are widely regarded as key components for achieving high-performance lithium-ion batteries. However, research on the multiscale effects of anode microstructures remains lacking in depth. The influence of transport and reaction processes within the microstructure on overall battery performance requires a coupling investigation integrating both electrochemical and physical field data. In this study, we construct a two-dimensional (2D) multi-physics model and simulate the 2D geometry and internal electrochemical processes to investigate the multiscale effects of microstructures on overall battery performance. Concurrently, we design three distinct anode structures: porosity gradient distribution structures, hard carbon–graphite composite anodes, and hard carbon-coated graphite anodes to identify structural features that enhance key battery performance metrics. Additionally, we analyze the distribution of side-reaction products and the Li+ concentration to reveal the influence of different microstructures on internal mass transport and electrochemical reactions. We also identify the factors within these three structures that contribute to extending battery lifespan and improving overall performance. This work systematically establishes the relationship between anode microstructures and battery performance, providing insights that are expected to optimize materials, reduce trial-and-error, and use simulations to guide experimental work more efficiently.