Title of article :
Synthesis and electrochemical characterization of amorphous MnO2 for electrochemical capacitor
Author/Authors :
Bao، نويسنده , , Shu-Juan and He، نويسنده , , Ben-Lin and Liang، نويسنده , , Yanyu and Zhou، نويسنده , , Wenjia and Li، نويسنده , , Hu-Lin، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2005
Abstract :
Amorphous MnO2 was synthesized by an improved reduction reaction. The synthesized product was characterized physically by thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD) and transmission electron microscope (TEM). Electrochemical characterization was performed using cyclic voltammetry and chronopotentiometry in a 0.5 mol/L Na2SO4 aqueous solution electrolyte. The prepared materials remained amorphous until 300 °C and then transformed to crystalline α-MnO2 at 400 °C. A specific capacitance of approximately 242 F/g was obtained by annealing at 200 °C. Annealing temperatures higher than 200 °C resulted in a decline of the specific capacitance. The specific capacitance of MnO2 annealed at 200 °C remained constant up to 400 cycles.
Keywords :
Electrochemical capacitors (ECs) , Amorphous , MnO2
Journal title :
MATERIALS SCIENCE & ENGINEERING: A
Journal title :
MATERIALS SCIENCE & ENGINEERING: A