Table 2.

Characteristic values were deduced from the measured impedance spectra by means of fitting the equivalent electrical circuit (EEC) shown in Fig. 3.

Zone	Rs (Ω cm2)	Rdiff (Ω cm2)	CPEdiff (S·sacm−2)	a1	Rct (Ω cm2)	CPEdl (μS·sacm−2)	n2	L (kH∙cm2)	RL (Ω cm2)
head	12	501	1.6·10−3	0.82	2196	26	0.84	67	19,000
valley	10	1154	0.8·10−6	0.99	3189	30	0.83	63	18,000
Tip	10	1040	1.3·10−3	0.81	2928	25	0.85	81	12,000