The effect of adding a non-ionic surfactant to disperse oxide particles on the electrochemical performance of PAni/LiMnNiO4 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/LiMnNiO4 L306 composite showed a better electrochemical performance than each single component and other composites (PAni/LiMnNiO4 L405 and PAni/LiMnNiO4 L603). The electrical conductivity of this composite reached 21.7Scm−1, and an initial discharge capacity of 198mAhg−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.