关键词: 凹凸棒石, 氮掺杂, 碳, NiCo₂O₄, 电极材料, 超级电容器

Abstract:

In this work, the attapulgite-supported nitrogen-doped carbon (ANC) was prepared by in-situ chemically polymerizing polyaniline coating upon attapulgite, followed by high temperature heat treatment, and then NiCo₂O₄was reacted onto the surface of ANC by a combination of hydrothermal reaction and calcination to synthesize ANC@NiCo₂O₄ composites. The chemical composition and morphology of the samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption/desorption. The electrochemical properties were evaluated by means of constant current charge discharge (GCD) and cyclic voltammetry (CV). The results showed that due to the high specific surface area and porous structure of ANC, the NiCo₂O₄ particles were uniformly located on the surface, resulting in large contact reaction areas with the electrolyte and improved electrochemical performance. At a current density of 1 A·g^-1, the specific capacitance was up to 945.5 F·g^-1, while at a current density of 16 A·g^-1, it was 587.6 F·g^-1, i.e., the capacitance retention was 62.1%, revealing a better rate performance. After 2000 cycles of charge-discharge process at a high current of 12 A·g^-1, the capacitance retention was 74.1%, higher than 48.7% of pure NiCo₂O₄, which indicated that the as-prepared composite electrode materials had excellent electrochemical durability.

Key words: Attapulgite, Carbon, Nitrogen-doped, NiCo₂O₄, Electrode material, Supercapacitor