Ni-Co hydroxide nanoneedles embedded in graphene hydrogel as a binder-free electrode for high-performance asymmetric supercapacitor
| Autor: | Yuanzhe Piao, Xuanzhen Jin, Kwang-dong Seong, Jeongmin Kang, Chaedong Lee, Wytse Hooch Antink, Dae Kyom Kim, Minsik Hwang |
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| Rok vydání: | 2018 |
| Předmět: |
Supercapacitor
Materials science Graphene General Chemical Engineering Composite number 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Capacitance 0104 chemical sciences law.invention chemistry.chemical_compound Chemical engineering chemistry law Electrode Electrochemistry Hydroxide 0210 nano-technology Power density Nanosheet |
| Zdroj: | Electrochimica Acta. 270:156-164 |
| ISSN: | 0013-4686 |
| Popis: | Ni-Co hydroxide nanoneedles embedded in graphene hydrogel are fabricated using an efficient two-step method and further explored as a binder-free electrode for high-performance asymmetric supercapacitors. First, freestanding graphene hydrogel is prepared via reduction in a mild condition. Second, Ni-Co hydroxide nanoneedles embedded in graphene hydrogel are obtained using a simple hydrothermal method. The existence of many hydrophilic functional groups in graphene hydrogel results in the generation of well-dispersed Ni-Co hydroxide nanoneedles throughout the graphene nanosheet. Moreover, the freestanding property of graphene hydrogel allows it to be used as a binder-free electrode, which can improve the energy density of the asymmetric supercapacitor without inhibiting its high power capabilities. The composite shows an excellent capacity of 544 C g−1 at 2 A g−1 in a three-electrode system. Moreover, the binder-free asymmetric supercapacitor achieves excellent performance with an energy density of 32.74 Wh kg−1 at a power density of 320 W kg−1 and good cycling stability with 85% capacitance retention at a current density of 10 mA cm−2 after 5000 cycles. Therefore, the Ni-Co hydroxide nanoneedles embedded in graphene hydrogel have immense potential as electrochemically active materials for the development of high-performance supercapacitors. |
| Databáze: | OpenAIRE |
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