Modeling Stress and Strain Energy in Battery Electrodes Under Cyclic Electrochemical Loading

The irreversible cyclic strain/stress in battery electrodes during ion intercalation/deintercalation drives mechanical energy dissipation, accelerating cycle life degradation. However, the lack of quantitative methods to assess stress and mechanical energy dissipation hinders a mechanistic understanding of mechanical behavior in electrochemical systems. This work aims to develop a theoretical framework to quantify stress and strain energy evolution in practical heterogeneous composite electrodes. Under assumptions of plane stress and elastic deformation, the average stress/strain energy per cycle can be derived for battery electrode during dynamic ion insertion/extraction. By considering a concentration-dependent modulus, the present framework allows for the simultaneous determination of both the bilayer stress, the apparent and local modulus of the electrode through measurements of its curvature and intrinsic chemical strain.