Browsing by Author "Peçenek, H."

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Open Access
The effects of stage house coupling on multipurpose auditorium acoustics
(Elsevier, 2022-03-01) Peçenek, H.; Yetiman, S.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
Nitrogen-doped composites have the potential to achieve well electrochemical performance by enabling convenient contact of the electrolyte ions for carbon-based materials. A good combination of metal oxide and carbonaceous material is a critical challenge in the development of composites. Herein, we demonstrate a highly capacitive and superior cycle performance of MnO2 based supercapacitor electrodes. The addition of different forms of carbon nanomaterials (carbon nanotube and graphene) and MXene is particularly studied. MnO2 based composite materials are capable of capacitance retention over 95%, with high specific capacitance compared to pure N-doped MnO2. The highest specific capacitance was achieved with MXene based MnO2 composite, which exhibits 457 Fg-1, at a current density of 1 A g−1 with extreme cycling efficiency (102.5%, after 1000 cycles). High conductivity and large surface area are stimulated by the propitious interaction between MnO2 and nanoscale materials, resulting in superior supercapacitor efficiency. This study highlights the possible potential of carbon-based MnO2 composite electrodes which could be useful for future energy storage applications.
Embargo
Highly compressible binder-free sponge supercapacitor electrode based on flower-like NiO/MnO2/CNT
(Elsevier BV, 2022-08-25) Peçenek, H.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
The increasing demand for flexible electronics encourages the innovative and functional designs of electrode materials with high performance and compressibility. In this work, we report a compressible supercapacitor electrode which is prepared by coating electrically active NiO/MnO2/carbon nanotube (CNT) composite onto a sponge. A cube of sugar was used as the template to obtain the sponge through infiltration and cross-linking of polydimethylsiloxane (PDMS). NiO/MnO2/CNT was deposited on the PDMS sponge to generate substantial amount of interface, resulting in a specific capacitance of 23 F/g at 0.1 A /g in a three-electrode system and 1.32 F/g at 0.5 mA in a symmetric supercapacitor. The proposed system exhibits excellent cycling stability with capacitance retention over 10.000 cycles. The strong adhesion of the binary metal oxides and carbon material onto the porous nonconductive sponge enables mechanical stability under compression-release cycles. Our study indicates that this electrode is a promising candidate for applications in flexible electronics. Furthermore, this research might guide the development of flexible, high-performance, and low-cost electrodes, which will be useful in wearable energy storage systems.
Open Access
Microwave-assisted fabrication of high-performance supercapacitors based on electrodes composed of cobalt oxide decorated with reduced graphene oxide and carbon dots
(Elsevier, 2022-05) Yetiman, S.; Peçenek, H.; Onses, M. Serdar
This study presents microwave-assisted preparation of cobalt oxide (Co3O4) based nanocomposite electrodes doped with carbon dots and reduced graphene oxide. The calcination of the precursors at 400 °C for 2 h results in nanocomposites. A three-electrode cell in 2M KOH solution is used for the electrochemical measurements. The carbon dot containing electrodes enables the highest specific capacitance of 936 Fg−1 at 0.5 Ag−1 current density. Specific capacitances of pure Co3O4, and Co3O4@RGO electrodes are 448 Fg−1 and 482 Fg−1 at 0.5 Ag−1, with good rate capability even at 10 Ag−1, respectively. The cyclic stability of the electrodes is reasonably high and the electrodes retain 93%, 87%, and 88% of their initial capacitance after 10,000 cycles for Co3O4, Co3O4@RGO, and Co3O4@RGO@CDs, respectively. The optimized Co3O4@RGO@CDs electrodes were used to fabricate a symmetric supercapacitor that exhibits high specific capacitance (126 Fg−1 0.25 Ag−1) and long cycle life (%81 retention after 10,000 cycles). The fabricated supercapacitor has energy density of 17.5 Wh kg−1 and power density of 2522 W kg−1. The outstanding results demonstrate the promise of carbon dots doped transition metal oxides-based nanoparticles as promising electrodes for supercapacitor applications.
Open Access
Outstanding supercapacitor performance with intertwined flower-like NiO/MnO2/CNT electrodes
(Elsevier Ltd, 2022-01-11) Peçenek, H.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
Binary metal oxides have been broadly investigated as a new electrode material for supercapacitor applications owing to their high reversible performance and good conductivity. When compared to a single candidate, the composite's electrochemical performance is considerably improved by the unique mix of pseudo-material and carbon material. Herein, we report a facile and rational synthesis procedure to fabricate a high performance supercapacitor electrode. The prepared NiO/MnO2/ carbon nanotube (CNT) composite has wonderfully stratified flower-like morphology. The positive synergism among components and unique structure has enabled a high specific capacitance of 1320 F/g at 1 A g−1. After 3000 cycles, the supercapacitor maintains more than 90% of its initial capacitance. Moreover, we also successfully prepared a symmetrical supercapacitor which is made up of two pieces of composite electrode separated with a membrane. The findings highlight that NiO/MnO2/CNT composite is highly desirable for future hybrid energy storage applications.