An electrochemical cell is presented. The cell includes a housing having an interior surface defining a volume, and an elongated separator disposed in the housing volume. The elongated separator defines an axis of the cell. The separator has an inner surface and an outer surface. The inner surface of the separator defines a first compartment. The outer surface of the separator and the interior surface of the housing define a second compartment having a volume. The cell further includes a conductive matrix disposed in at least a portion of the second compartment volume such that the conductive matrix occupies a gap between the outer surface of the separator and the interior surface of the housing. The gap in the second compartment extends in a direction substantially perpendicular to the axis of the cell.