| Supercapacitors, as a novel energy storage devices between secondary battery and physical capacitor, have broad prospects in application. In recent years, the researches about supercapacitors mainly focus on the preparation of electrode materials with high performance. Transition metal hydroxides, as supercapacitor electrode materials with excellent electrochemical performance, have become a research hotspot.1. In this work, a facile hydrothermal method with hexadecyltrimethyl ammonium bromide（CTAB） as the soft template is used to tune the morphology of Co（OH）2. Co（OH）2 samples with various morphology were obtained via controlling the content of CTAB, the reaction time. Simultaneously, the electrochemical performance was analyzed, which shows that the specific capacitance of Co（OH）2 nanowires electrode is 522 F/g at 0.5 A/g and the long-term performance for asymmetric supercapacitor assembled with NTAC is excellent.2. To obtain suitable nanostructures in favor of electronic and ionic transport process in the electrode for supercapacitor, a flower-like texture Ni（OH）2 was synthesized by a hydrothermal method. In addition, the formation mechanism of the flower-like Ni（OH）2 was investigated, which indicate that the flower-like texture was formed due to the stacked Ni（OH）2 nanoflakes with hexagonal β-phase and the dissolution-recrystallization process play important roles in the formation of flower-like texture Ni（OH）2. This Ni（OH）2 sample exhibits a high specific capacitance of 2653.2 F/g at 2 A/g due to its higher conductivity and the suitable macropores for ionic transport.3. Various nickel cobalt double hydroxide nanoflowers assembled by filmy nanoflakes with different Ni/Co ratios are obtained using template-free hydrothermal method. The sizes of these nanoflowers are easily tuned by the Ni/Co ratio in the precursors. Simultaneously, the formation mechanism of flower-like texture was investigated in detail. Ni0.28Co0.72（OH）2 as positive material and activated carbon as negative material were assembled the asymmetric supercapacitor with 19.4 Wh/kg at power density of 80.5 W/kg.4. To further improve the conductivity of Ni（OH）2, Ni（OH）2-GO composite was prepared. To enhance this contact, the exfoliated GO according to Hummers’ method is secondly oxidized processing for anchoring Ni（OH）2 nanoflakes. Specific capacitance, high-rate performance and long-term life of Ni（OH）2/TGO composite were improved compared Ni（OH）2/GO composite. |
