Synthesis of Nanosheet Crystallites of Ruthenate with an α-NaFeO2-Related Structure and Its Electrochemical Supercapacitor Property

Unilamellar crystallites of conductive ruthenium oxide having a thickness of about 1 nm were obtained via elemental exfoliation of a protonic layered ruthenate, H0.2RuO2·0.5H2O, with an α-NaFeO2-related crystal structure. The obtained RuO2 nanosheets possessed a well-defined crystalline structure with a hexagonal symmetry, reflecting the crystal structure of the parent material. The restacked RuO2 nanosheets exhibited a high pseudocapacitance of ∼700 F g−1 in an acidic electrolyte, which is almost double the value of the nonexfoliated layered protonated ruthenate.