In the negative electrode, Li is plated onto the lithium metal or dissolved into the electrolyte in the form of $\text{Li}^+$. The only contribution to the Gibbs free energy we consider is that of pure Li metal:

where $N$ is the number of Li atoms. When there is no Li present, $G_{\text{Li}} = 0$. There is also no configurational entropy associated with plating, since Li metal is a pure compound with no vacancies. Thus, we write the chemical potential as