Electrochemical performance of polyaniline electroless deposited La–Mg–Ni-based hydrogen storage alloys

Polyaniline (PANI) electroless-deposition is applied onto La–Mg–Ni-based La0.80Mg0.20Ni2.70Mn0.10Co0.55Al0.10 hydrogen storage alloy powders in order to improve electrochemical and kinetic properties. FE-SEM and FT-IR results reveal that coral-like PANI particles are deposited on the surface of the alloy. Owing to the PANI coating the initial discharge capacity of the alloy electrodes increases from original 174 mAh g−1 to 226 mAh g−1, the capacity retention rate at 200 cycles (S200) increases from 85% to 88%, and the high rate discharge ability (HRD) is scaled up by 18% at discharge current density of 1500 mA g−1. Linear polarization, EIS, anodic polarization and potential static step discharge measurements indicate that charge transfer resistance decreases and the hydrogen diffusion rate increases after PANI-coating.

► We study the effect of PANI on electrochemical properties of La–Mg–Ni-based alloys. ► The PANI improves the initial activation property. ► It enhances HRD remarkably.