Figure 2.
The diagram represents a solid particle with boundary conditions for lithium concentration. On the left side, at radius equals zero, the partial derivative of concentration with respect to radius equals zero. On the right side, at radius equals particle radius, the negative product of diffusion coefficient and concentration gradient equals current over Faraday constant. The half-sphere shape illustrates the radial direction from the centre to the surface of the solid particle, labelled as radius equals particle radius.Schematic representation of the boundary conditions for the lithium-ion concentration within the solid phase