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Platanus fruit-like nickel cobalt ammonium phosphate/MWCNTs composites for high-performance supercapacitors were successfully prepared by a two-step hydrothermal method using NiSO[Formula: see text]6H2O, CoSO[Formula: see text]7H2O, (NH4)H2PO4 and MWCNTs as raw materials, respectively. The effects of MWCNTs addition on the structure and properties of the composites were investigated. The results showed that when the doped amount of MWCNTs is 7.3[Formula: see text]wt.%, the as-prepared NCAP/M7.3 composite presented an obvious platanus fruit likeness, its surface is rough and porous with a diameter of 3–5[Formula: see text][Formula: see text]m. Compared with the other MWCNTs contents, the NCAP/M7.3 electrode obtained under this condition showed the best capacitive performance. The discharge specific capacity was up to 1270[Formula: see text]F[Formula: see text]g[Formula: see text] at current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text], which remains to be 902[Formula: see text]F[Formula: see text]g[Formula: see text] even at a high density of 10[Formula: see text]A[Formula: see text]g[Formula: see text]. The results show that the target sample can be the ideal electrode material for supercapacitor.

As one of the important components of the supercapacitor, electrode material has a significant influence on the electrochemical performance of the device. In this study, Ni2(NO3)2(OH)2 · 2H2O/(Co(NH3)5(N3))(N3)2 (NC) composite material was prepared by the microwave-assisted method. The effects of Al(NO3)3 contents on the morphology and structure of the composites were studied by scanning electron microscopy, X-ray diffraction, Raman spectrum, and laser particle size distribution analyzer. The capacitive properties of the composite were analyzed by cyclic voltammetry, constant current charge and discharge, and electrochemical impedance spectroscopy measurements. The results show that the Al(NO3)3 has a significant effect on the morphology and capacitance of NC. When the contents of Al(NO3)3 are 0, 5, 10, 15, and 20 wt%, the discharge capacities of NC, NCA-5, NCA-10, NCA-15, and NCA-20 samples obtained under 1 A/g current density are 1674, 1759, 2645, 1098, and 1321 F/g, respectively. At higher current densities of 4, 7, and 10 A/g, the discharge specific capacities reached 1350, 1064, and 894 F/g, indicating that the NCA-10 composite is a promising electrode material for supercapacitors.

To construct novel multicomponent transition metal oxides with the synergistic effect is always the most important strategy to improve the electrochemical performance of supercapacitor electrode materials. Here, a new type of parallelogram-like NH4CoPO4 · H2O/Ni3(PO4)2 · 8H2O/MnO2 (NNM) composites were successfully prepared by a simple hydrothermal method, and the addition amount of MnO2 was adjusted in detail. The morphology, structure, composition, particle size, and distribution of the electrode were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectrum, and laser particle size analyzer. The results showed that when MnO2 was added at 9.7 wt%, the resulting NNM-9.7 composite exhibited a parallelogram-like morphology with an average length, width. and thickness of 5, 3, and 0.2 µm, respectively. The results of cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) show that the NNM-9.7 electrode has large specific surface area, good conductivity, and abundant porosity, which makes it to have high-specific capacity (1180 F g−1, 1 A g−1) and excellent rate retention (980 F g−1, 10 A g−1) when compared with other electrodes, which is better than most reported electrodes of nickel–cobalt oxides/hydroxides. These results indicate that the novel NNM-9.7 composite with parallelogram-like shape and its synthesis method may provide a feasible solution for supercapacitors' material issues.