Capacitive Behavior of Birnessite-Type Manganese Oxide Films Intercalated with Various Metal Ions

Abstract

Various metal ions (Na+, Ca2+, Co2+, Ni2+, and Pb2+) were intercalated between the manganese oxide layers grown anodically on a Pt substrate. The films were subjected to a repetitive charge-discharge cycle test in an aqueous electrolyte of Na2SO4 between 0 and +0.8 V (vs Ag/AgCl). When the number of cycles increased, remarkably increased capacitances due to pseudocapacitance were observed for the manganese oxide films intercalated with Co2+, Ni2+, and Pb2+, accompanying drastic morphology changes where the multilayers lying parallel to the substrate before cycling were aligned vertically.