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Fabrication of Pb and PbO2 nanostructures was undertaken with the aim of building low cost lead acid micro-batteries with high performance. Despite environmental problems and the relatively low specific energy in comparison with other galvanic generators, lead acid batteries are still extensively used in the field of energy accumulation, owing to a well known and reliable technology. Thus, it is of high technological interest to develop procedures for fabricating these devices at a micrometer scale or less. PbO2 nanowires were grown in different electrochemical deposition conditions leading to pure -PbO2, pure -PbO2 and  mixture [1-2]. Several parameters, like temperature, electrolyte composition, deposition time and power supply (potentiostatic and galvanostatic), have been investigated to elucidate their influence on morphology, composition and structure of lead dioxide nanostructures. Pb nanowires, cathodically deposited from Pb2+ based baths, also in the presence of several additive, showed poor features in terms of geometrical regularity, and uniformity of filling of template. The unsatisfactory results, forced us to experience an “indirect” method to obtain Pb nanowires within template pores. The procedure consists of an anodic electrodeposition of -PbO2 nanowires, followed by their in-situ reduction to metallic lead [3]. Both these processes occurred at a high rate, so that the indirect method led to a complete filling of template pores with pure polycrystalline Pb in short times and with high current efficiency. References 1 R. Inguanta, S. Piazza and C. Sunseri, J Electrochem. Soc. 155 (2008) K205. 2 R. Inguanta, F. Vergottini, G. Ferrara, S. Piazza, C. Sunseri, Elettrochimica Acta, Submitted. 3 R. Inguanta, E. Rinaldo, S. Piazza, C. Sunseri, Electrochem. Solid-State Lett. 13 (2010) K1

Metallic lead was deposited, both in form of bulk films and nanowire array within pores of anodic alumina membranes, following a new two-step procedure, consisting in anodic electrodeposition of α-PbO2, followed by its reduction to metallic lead. This method allows to overcome drawbacks of the “direct” electrodeposition of lead from aqueous solution, consisting, essentially, in the formation of dendritic deposits. Here, we report the comparison between results obtained in the two cases and discuss the kinetic of oxide reduction both for films and nanowires. Deposit morphology and structure are also discussed. We have found that reduction of α-PbO2 films proceeds always at high speed and unitary efficiency, with the formation of polycrystalline compact films. Unfortunately, these films present cracks due to the volume shrinkage accompanying the conversion of α-PbO2 into Pb metal. In addition, α-PbO2 nanowires reduction proceeds up to a complete conversion to metallic Pb, which present a characteristic “sausage-like” shape caused by the lower molar volume of metal with respect to oxide.

Metallic lead nanowires were deposited within pores of commercial anodic alumina membranes having an average pore diameter of 210 nm. "Direct" electrodeposition was attempted from 0.1 M Pb(NO 3 ) 2 aqueous solution with a variable concentration of H 3 BO 3 as a chelating agent, but it gave unsatisfactory results. An "indirect" two-step deposition procedure was then adopted, consisting of the anodic electrodeposition of α-PbO 2 nanowires, followed by their in situ reduction to metallic lead. Both these processes occurred at a high rate so that the indirect method led to a complete template pore filling with pure polycrystalline Pb in short times and with a high current efficiency.