Nickel hydroxide nanoparticles and their hybrids with carbon nanotubes for electrochemical energy storage applications

Abstract

The β-Ni(OH)2 nanoparticles and their nanohybrid with 5% CNTs have been synthesized by facile hydrothermal and ultra-sonication method. The structural and phases analysis of the prepared sample was investigated by XRD and FT-IR analysis. The effect of CNTs on the electrical and electrochemical properties of the nanohybrid was determined via current-voltage (I-V) and electrochemical measurements. The observed higher electrical conductivity (1.37 × 10−2 Sm−1) of the β-Ni(OH)2@CNTs nanohybrid than the Ni(OH)2 nanoparticles (1.2 × 10−8 Sm−1) was due to the effective interaction between the CNTs and Ni(OH)2 nanoparticles. Moreover, the higher gravimetric capacitance (724 Fg−1) and lower charge transfer resistance (Rct) of the nanohybrid was also observed. This was due to the synergistic effects between the electrolytic double-layer capacitance (EDLC) of the CNTs and pseudocapacitance (PSCs) of the Ni(OH)2 nanoparticles (NPs). The evenly distributed CNTs not only act as a capacitive supplement but also support the faradic reaction in the Ni(OH)2 nanoparticles to enrich the gravimetric capacitance. The observed results express the potential of the β-Ni(OH)2@CNTs nanohybrid as a positive electrode for modern energy storage devices.

Keywords

• Hydrothermal route
• Nanohybrid
• Synergistic effects
• Gravimetric capacitance