The electrochemical properties of [formula omitted]/polyaniline composites

Abstract

The La 0.7Mg 0.25Ti 0.05Ni 2.975Co 0.525 (AB 3) alloy was modified with different contents of polyaniline (PANI) through ball milling. XRD, SEM and FTIR were used to characterize the properties of the AB 3 / x PANI composites ( x = 1 , 2, 3 and 4 wt%). The effects of PANI on the electrochemical properties of AB 3 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 AB 3 alloy but decreased the average particle size of AB 3 alloy. The charge–discharge results indicated that the maximum discharge capacity of AB 3 alloy electrode decreased with the addition of PANI. However, the discharge cycle stability of AB 3/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 AB 3/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 AB 3/PANI composite electrode exhibited an optimal electrochemical kinetic property.