Effect of electroplating polyaniline on electrochemical kinetics of La-Mg-Ni-based hydrogen storage alloy

A new polyaniline (PANI)-coated technique is adopted for the La-Mg-Ni-based alloy La0.80Mg0.20Ni2.70Mn0.10Co0.55Al0.10 in order to advance its electrochemical kinetic characteristics. In this treatment, the aniline monomers are electroplated on the alloy particles to form polyaniline films. FE-SEM observation and UV-vis analysis results revealed that the coral-like atrovirens PANI particles are deposited on the surface of the alloy. Through the PANI-coating the capacity retention rate at the 200th cycle of the La-Mg-Ni-based alloy electrodes amounts up from original 82.3% to 86.4% and the high rate discharge ability increased from 24.7% to 35.6% at a discharge current density of 1500 mA g(-1). Linear polarization, anodic polarization and cyclic voltammetry measurements suggest that charge-transfer resistance decreases and the hydrogen absorption rate of the alloys increases after PANI-coating. (C) 2012 Elsevier B.V. All rights reserved.