Electrochemical performance evaluation of polyaniline/lithium manganese nickel oxide composites synthesized using surfactant agents

The effect of adding a non-ionic surfactant to disperse oxide particles on the electrochemical performance of PAni/LiMnNiO(4) composites is evaluated by using cyclic voltammetry (CV), impedance measurements and constant-current charge/discharge cycling techniques. Three surfactants based on ethoxylated (EO) and propoxylated (PO) lauryl alcohols (3EO/6PO, L306; 4EO/5PO, L405; and 6EO/3PO, L603) were investigated. For comparative purposes, the oxide and polyaniline were prepared by sol-gel and chemical methods and were also investigated for their physical and electrochemical performances. By galvanostatic charge-discharge tests, the PAni/LiMnNiO(4) L306 composite showed a better electrochemical performance than each single component and other composites (PAni/LiMnNiO(4) L405 and PAni/LiMnNiO(4) L603). The electrical conductivity of this composite reached 21.7 S cm(-1), and an initial discharge capacity of 198 mAh g(-1) was obtained. After 21 cycles, the retention capacity was 91%. These results indicate a synergistic effect among the materials in the composite. Analytical techniques, such as scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were also used to characterize the composite materials. (C) 2009 Elsevier B.V. All rights reserved.