A phenomenon which was not yet described is observed in the potential course of a lithium metal counter electrode (CE) employed for investigations of porous graphite electrodes (WE). The potential characteristics of the CE were found to be strictly connected to the lithium concentration in the active material of the WE. The authors suggest that the observed phenomena at the CE are related to changes of the current density distribution across the thickness of the porous WE. The local depletion/enrichment of lithium in the pores affects the lithium concentration gradient in the electrolyte which results in changes of the overpotential at the CE. This relation may be used prospectively to study the current density distribution in porous electrodes as a function of time, C - rate and state of charge. (C) 2015 Elsevier B.V. All rights reserved.