A microwave synthesis of mesoporous NiCo2O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors

© 2015 Wiley-VCH Verlag GmbH & Co. KGaA , Weinheim. A facile microwave method was employed to synthesize NiCo2O4 nanosheets as electrode materials for lithium-ion batteries and supercapacitors. The structure and morphology of the materials were characterized by X-ray diffraction, fieldemission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller methods. Owing to the porous nanosheet structure, the NiCo2O4 electrodes exhibited a high reversible capacity of 891 mAhg-1 at a current density of 100 mAg-1, good rate capability and stable cycling performance. When used as electrode materials for supercapacitors, NiCo2O4 nanosheets demonstrated a specific capacitance of 400 Fg-1 at a current density of 20 Ag-1 and superior cycling stability over 5000 cycles. The excellent electrochemical performance could be ascribed to the thin porous structure of the nanosheets, which provides a high specific surface area to increase the electrode-electrolyte contact area and facilitate rapid ion transport.