NiMn₂O₄ Nanosheet Arrays with Controlled Mass Loading as Pseudocapacitor Electrodes

Abstract:

Nanostructured binary transition metal oxides are expected to possess better pseudocapacitive performance than that of mono-metal oxides. Herein, NiMn₂O₄ nanosheet arrays are grown on the Ni foam successfully with using the facile hydrothermal method and post-annealing. The surface morphology, composition and structure of as-synthesized products are investigated by Field emission scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray diffraction. The electrochemical performance is evaluated by cyclic voltammetry and galvanostatic charge-discharge tests. The results show that the thickness of nanosheets varied from 7 nm to 25 nm with changing the reaction temperature from 40 to 220 oC, the density of nanosheets are also present the increasing trend, and through which the mass loading of as-synthesized nanostructurs is controlled. The NiMn₂O₄ electrodes fabricated at higher reactiontemperature exhibit better electrochemical performance due to the raising mass loading of active electrode materials with the temperature. Moreover, the electrodes achieved at 220 oC offer a highest specific capacitance of 177.2 mF/cm² at scan rate of 2 mV/s and good cycling stability with 89 % initial capacitance retention after 5000 cycles at a current density of 10 mA/cm² in 1 M Na₂SO₄ electrolyte.

• Periodical: Key Engineering Materials (Volume 727)
• Pages: 678-682
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.727.678
• Online since: January 2017
• Authors: Lu Xiang, Jun Shen, Lu Qiang Lv, Xu Li, Shuang Yi Liu, Zhen Hu Li
• Keywords: Mass Loading, Nanosheet Arrays, NiMn₂O₄, Pseudocapacitor

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