Abstract: Birnessite type layered manganese oxide with flower-like morphology was synthesized via low-temperature hydrothermal treatment in weak acidic KMnO₄ solution.Effects of temperature and surfactants on the morphology and structure of the product were investigated.The as-prepared material was characterized by XRD，SEM，and N₂ adsorption-desorption.Specific capacitance of layered manganese oxide with flower-like morphology reached as high as 190 F/g at a sweep rate of 5 mV/s in 1 mol/L Na₂SO₄ solution.

Key words: layered manganese oxide, flower-like, KMnO₄, specific capacitance