Meaning
Mutual interaction between electrochemical reactions and mechanical stress fields alters mass transport rates and mechanical deformation inside battery electrodes. Through chemomechanical coupling, lithium insertion creates internal strain that modifies chemical potential and reaction kinetics. The bidirectional feedback loop means mechanical pressure alters cell voltage, while ionic concentration changes drive physical swelling.
This interaction governs solid-state battery interfaces and high-capacity anode performance, stopping at equilibrium where mechanical stress cancels the electrochemical driving force.
Stress Kinetics
Concentration gradients generated during fast charging produce non-uniform volume expansion across active cathode particles. Under chemomechanical coupling, compressive stress near particle surfaces suppresses further lithium ion intercalation. Diffusion coefficients decrease under high hydrostatic pressure.
Reduced ionic mobility increases overpotential and accelerates capacity fade.
Lattice Deformation
Phase transformations during cycling generate severe interfacial shear forces between adjacent crystal grains. Within solid electrolyte separators, chemomechanical coupling causes localized plastic deformation at lithium metal contact points. Microstructural defects concentrate stress, triggering dendrite nucleation through soft solid phases.
Elastic strain energy accumulates until fracture strength falls below applied mechanical loads.
Failure Boundary
Mechanical containment pressure during cell operation shifts phase stability limits and cell polarization. In commercial pack design, chemomechanical coupling sets maximum allowable clamping force to prevent internal degradation.
