Abstract <p>Mechanical-diffusion coupling behavior and interaction mechanisms between the chemical and strain fields become increasingly important since that the extensive applications of biosensors, artificial muscles and actuators in the non-uniform molar concentration environment. Nevertheless, in such condition, the influences of the inherent high-order molar concentration-dependent material properties of diffusing substance on the diffusion-mechanical responses are still not explored and reported. To address the deficiency, this paper establishes a new non-Fick diffusion-mechanical model with the high-order molar concentration dependency of diffusing substance. To directly solve the nonlinear multi-filed differential governing equations, the nonlinear time-domain finite element method based on virtual work principle is developed, which is applied to investigate the impact responses of 2D thick circular plate subjected to transient shock loadings of molar concentration. The dimensionless numerical results indicate that the high-order molar concentration-dependent material parameters lower the harmful unwanted impact mechanical-diffusion responses and elevated the diffusive/elastic wave propagation speed.</p>