The formation of nanoporous membranes from anodically oxidized aluminium and their application to Li rechargeable batteries

A method for the preparation of nanoporous dielectric membranes from anodically oxidized aluminium is described. Pores of an initially formed free anodic alumina film were protected with gelatin gel, and the oxide barrier layer was chemically dissolved from bottom side of the film. The method is advantageous in that it permits complete removal of the barrier layer and fabrication of large-area fine porous membranes without introducing discontinuities in the pore network across the membrane surface. The membranes produced here were investigated by scanning electron microscopy and preliminarily examined as an electrolyte carrier/separator for Li rechargeable batteries by impedance measurements and charge-discharge cycle experiments. Repeated electrodeposition- dissolution of Li metal on Ni and Al substrates in LiPF6/propylene carbonate electrolyte was performed through the alumina membrane or through a commercially available polymeric separator, and charge-discharge coulombic efficiencies were then calculated. (C) 2001 Elsevier Science Ltd. All rights reserved.