Electrochemical characterization of Nickel Hydroxide electrodes with MWCNT

Abstract

Alkaline secondary batteries are widely required in the current market of electronic devices. Particularly, nickel hydroxide active material is the positive electrode in Ni/H2 and Ni/MH batteries. Due to their semiconductor nature, it becomes necessary to solve this limitation. A poor electrical contact yields ohmic overpotential and capacity loss at high currents. The carbon nanotubes (CNT) employed as additive was first studied by Lvetal.[1] who found that the addition of NTC may improve battery performance at high download speeds. However, discussions about the way that CNT affect structural and kinetic parameters are still acking. In this work, the addition of multiwall carbon nanotubes (MWCNT) is investigated. The active material was prepared by hydrothermal synthesis method. The characterization was performed by optical (SEM, TEM, XRD) and electrochemical techniques (charge‐discharge cycles, cyclic voltammetry, electrochemical impedance spectroscopy ‐ EIS). The EIS technique along with a physicochemical model developed in the laboratory, are powerful tools for the estimation of physicochemical and structural parameter such as: specific active area, effective conductivity and diffusion coefficient of H+[2]. This knowledge allows electrochemical performance optimization of the systems.