where ΔV is the change in volume due to intercalation, and V0 is the reference volume.

where I is the identity tensor. In a geometrically nonlinear context, the intercalation strain is represented by a deformation gradient,

The Intercalation Strain subnode is only available with the Battery Design Module, see https://www.comsol.com/products/specifications/).

Select how to define the Volumetric strain, ΔV/V0, — From material or User defined.

When From material is selected, the material property Volumetric strain is used. The dependency on the concentration is then passed to the material using the input in the Model Input section.

For User defined, enter an expression for the volumetric strain as function of a concentration variable. As the strain is given explicitly, such an expression should be a function of a concentration variable.

Physics tab with Linear Elastic Material or Nonlinear Elastic Material node selected in the model tree: