Investigation on micromorphology and electrochemical kinetics of La-Mg-Ni-based alloy chemically modified by nanopolypyrrole

In order to improve the electrochemical kinetics of La-Mg-Ni-based alloy, the chemical modification of polypyrrole (PPy) doped with sodium sulfate (Na2SO4) has been applied on the surface of the La-0.80 Mg0.20Ni2.70Mn0.10Co0.55Al0.10 alloy particles. SEM, TEM, and FT-IR results indicate that the spongy nano-PPy successfully forms on the surface of the alloy particles and that the PPy nanoparticles distribute uniformly. Owing to the nano-PPy, which possesses excellent electrochemical redox reversibility, electrocatalytic activity, and high conductivity, electrochemical kinetics of the alloy electrode is remarkably ameliorated. The high-rate dischargeability (HRD) of the treated alloy electrode at 1800 mA g(-1) reaches two times of that for the bare alloy, meanwhile the discharge voltages increase obviously. The charge transfer resistance (R (ct)) of treated alloy electrode markedly decreases; the limiting current density (I (L)) and the hydrogen diffusion coefficient (D) increase.