Browsing by Subject "MnO2"
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Item Open Access Electric-field-induced reversible phase transitions in a spontaneously ion-Intercalated 2D metal oxide(American Chemical Society, 2021-05-12) Rasouli, Hamid Reza; Kim, J.; Mehmood, Naveed; Sheraz, Ali; Jo, M. K.; Song, Seungwoo; Kang, K.; Kasırga, Talip SerkanElectric field driven reversible phase transitions in two-dimensional (2D) materials are appealing for their potential in switching applications. Here, we introduce potassium intercalated MnO2 as an exemplary case. We demonstrate the synthesis of large-area single-crystal layered MnO2 via chemical vapor deposition as thin as 5 nm. These crystals are spontaneously intercalated by potassium ions during the synthesis. We showed that the charge transport in 2D K-MnO2 is dominated by motion of hydrated potassium ions in the interlayer space. Under a few volts bias, separation of potassium and the structural water leads to formation of different phases at the opposite terminals, and at larger biases K-MnO2 crystals exhibit reversible layered-to-spinel phase transition. These phase transitions are accompanied by electrical and optical changes in the material. We used the electric field driven ionic motion in K-MnO2 based devices to demonstrate the memristive capabilities of two terminal devices.Item 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.