Solid state reactions at metal/film interfaces: The case of the Pb/PbSO4 interface

► The discharge product of the Pb/PbSO4 interface can be described as a continuous metal/film interface. ► The continuous films at this interface have ionic resistivity 102-103 times lower than passivating films. ► These grown films on discharging can suffer partial disruption giving partial disrupted films which recrystallize giving porous external films. ► The Pb/PbSO4 interface gives under oxidation an exchange current density i0 of 44 mA cm−2 and an αa of 0.46. Under the reduction of aged films, i0 is 2.48 mA cm−2 and αc 0.95 (symmetric barrier).