Novel LiMn ₂O ₄ based cathode material with eco-friendly water-based binder consisting of conducting polymer poly-3,4-ethylenedioxythiopene/polystyrene sulfonate (PEDOT:PSS) dispersion and carboxymethylcellulose (СМС) is proposed. The morphology and the structure of the composite materials were investigated by X-ray diffraction, scanning electron microscopy, EDX analysis and XPS. The electrochemical properties of modified cathode materials of different composition were investigated by cyclic voltammetry, galvanostatic charge-discharge and by electrochemical impedance spectroscopy. The results were compared with those obtained for conventional PVDF-bound LiMn ₂O ₄ material. It was shown that the material with optimal composition consisting of 86 wt.% of LiMn ₂O ₄, 10 wt.% of carbon black and 4 wt.% of conducting polymer binder exhibited good rate capability with discharge capacity 126 mAh g ⁻¹ (at 0.2 C, normalized by LiMn ₂O ₄ mass) and 75 mAh g ⁻¹ at 10 C as well as good cycling stability at 1 C (less than 5% decay after 200 cycles). These functional characteristics were markedly better than for PVDF-bound LiMn ₂O ₄ material. The electrochemical impedance spectra reveal the significant decrease of interfacial resistance and an increase of apparent diffusion coefficients for LiMn ₂O ₄ cathode material with conducting polymer binder, which favor improved functional characteristics.