In this study, we prepared LiFePO4- poly (sodium 4-styrenesulfonate) (PSS) composite by the hydrothermal method and ball-milling process. Different wt% PSS were added to LiFePO4. The cathode electrodes were made from mixtures of LiFePO4-PSS: SP-270: PVDF in a weighting ratio of 70%: 25%: 5%. LiFePO4-PSS powders were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The electrochemical properties of LiFePO4-PSS/Li batteries were analyzed by cyclic voltammetry, charge/discharge tests, and AC impedance spectroscopy. A Li/LiFePO4- PSS battery with 4.75 wt% PSS shows the best electrochemical properties, with a discharge capacity of 128 mAh/g.