SYNTHESIS AND CHARACTERIZATION OF SOME CARBON/LAYERED DOUBLE HYDROXIDE FOR SUPERCAPACITOR APPLICATIONS


Öğrenci: MUSTAFA RAQEEB MOHAMMED

Danışman: Şaban Patat

In this work, nickel-manganese oxides/hydroxide/carbonate@activated carbon (AC),

NiMn layered double hydroxide@activated carbon and cobalt-manganese

oxide/hydroxide/carbonate@activated carbon composite electrode materials for

supercapacitor have been synthesized by a hydrothermal method from the solution of

metals salts and urea after the thermal hydrolysis of urea. Physical properties,

morphology, and specific surface area of the composites were characterized by X-Ray

powder diffraction (XRD), scanning electron microscopy (SEM) equipped with energydispersive

spectroscopy (EDX), DC conductivity and nitrogen absorption/desorption

measurements. SEM images confirmed the NiMn layered double hydroxide, Mn3O4,

MnCO3, NiCO3, Ni(OH)2, Co3O4, Co(OH)2 and CoCO3 dispersed on the external

surface of activated carbon particles.

The electrochemical performance of the composites was investigated by cyclic

voltammetry and galvanostatic charge/discharge measurements. The electrochemical

investigation shows that AC//AC@NiMn(1:1) and AC//AC@CoMn(1:1) asymmetric

supercapacitors (ASC) exhibit high energy and power densities, good rate capability and

excellent cycling stability, which can be attributed to the synergetic effects between the

conductivity of the activated carbon and the redox properties of the metal

oxide/hydroxide/carbonate. The AC//AC@NiMn(1:1) ASC operating at 1.2 V delivers a

high energy density of 5.5 Wh/kg-1 at a power density of 1000 W/kg-1 and excellent

cycling stability with 96% retention of initial capacitance after 5000 cycles. The

AC//AC@CoMn(1:1) ASC operating at 1.2 V delivers a high energy density of 4.9 Wh

/kg-1 at a power density of 1000 W/kg-1 and excellent cycling stability with 97%

retention of initial capacitance after 5000 cycles.

This work shows that nickel-manganese oxides/hydroxide/carbonate@activated carbon,

NiMn layered double hydroxide@activated carbon and cobalt-manganese

oxide/hydroxide/carbonate@activated carbon composite electrode materials were found

to be promising electrode materials for the supercapacitor working at high current

density.