Consider a battery that features the full cell reaction shown below:

$4Na+Fe{S}_{2}2N{a}_{2}S+Fe$

In the fully$-$charged state, this battery has a sodium metal negative electrode and a $Fe{S}_2$ positive electrode, as shown in the "Fully charged" schematic of the battery cell below. During discharge, assume that $N{a}^{+}$are transported in the electrolyte, and no other ionic species involved in the cell reaction are mobile in the cell. In the two empty boxes below, schematically draw the battery system at $50\%$ SOC and at full discharge, respectively. Pay close attention to the location of the phases within the cell, and be sure to label the phases $($including the electrolyte$).$

Electrolvte

Fully charged

SOC$=50\%$

Fully discharged