Analytical Design of Electrode Particle Debonding for Battery Applications

Abstract

A physics-based analytical methodology is presented to describe the debonding of a statistically representative electrochemically active particle from the surrounding binder-electrolyte matrix in a porous electrode. The proposed framework enables to determine the space of C-Rates and electrode particle radii that suppresses or enhances debonding and is graphically summarized into maps where four debonding mechanisms were identified: a) the spontaneous debonding mechanism, which occurs when the electrode particle spontaneously detaches from the matrix; b) the continuous debonding mechanism, which occurs when the electrode particle gradually loses contact with the surrounding matrix; c) the electrochemical cycling fatigue mechanism, which causes gradual growth of the flaw due to electrochemical cycling; and d) the microstructural debonding mechanism, which is a result of the microstructural stochastics of the electrode and is embodied in terms of the debonding probability of particles. The critical C-Rates for debonding demonstrate a mechanism-dependent power-law relation with respect to the particle radius, which enables the experimental identification of the failure mechanism thereby providing a context to formulate design strategies to minimize debonding and provide robust, physics-based, phenomenological, and statistics-based estimates for electrochemically driven failure.