The electrochemical properties of AB3AB3/polyaniline composites

The La0.7Mg0.25Ti0.05Ni2.975Co0.525 (AB3) alloy was modified with different contents of polyaniline (PANI) through ball milling. XRD, SEM and FTIR were used to characterize the properties of the AB3/xAB3/x PANI composites (x=1x=1, 2, 3 and 4 wt%). The effects of PANI on the electrochemical properties of AB3 alloy electrode were studied by charge–discharge, electrochemical impedance spectroscopy (EIS), linear polarization (LP) and potentiostatic discharge experiments. The XRD, SEM and FTIR results showed that ball milling did not change the characterizations of PANI and AB3 alloy but decreased the average particle size of AB3 alloy. The charge–discharge results indicated that the maximum discharge capacity of AB3 alloy electrode decreased with the addition of PANI. However, the discharge cycle stability of AB3/PANI composite electrodes increased firstly and then decreased with the increase in PANI content. The EIS and LP curves showed the same trends with the discharge cycle stability. The hydrogen diffusion coefficients of AB3/PANI composites were estimated from the potentiostatic discharge curves, indicated the opposite trend with the discharge cycle stability. When the PANI content was equal to 3 wt%, the AB3/PANI composite electrode exhibited an optimal electrochemical kinetic property.