Synthesis LiFePO4- poly(sodium 4-styrenesulfonate) composite cathode material for rechargeable lithium battery by hydrothermal method

Poly (sodium 4-styrenesulfonate) (PSS) is ionomer based on polystyrene that is electrical conductivity and isoviscosity. LiFePO4 has been a promising electrode material however its poor conductivity limits practical application. To enhance the electronic conductivity of LiFePO4, in this study we prepared LiFePO4- PSS composite by the hydrothermal method. LiFePO4 was heated at $170^{\circ}C$ for 12h and then different wt% PSS (0%, 2.91%, 4.75%, 7.36%, 10%) are added to LiFePO4 and milled at 300rpm for 10h. And then the obtained powders were subsequently heated at $500^{\circ}C$ for 1h under argon flow. The cathode electrode were made from mixtures of LiFePO4-PSS: SP-270- PVDF in a weighting ratio 75%: 25%:5%. The electrochemical properties of LiFePO4- PSS/Li batteries were analyzed by cyclic voltammetry and charge/discharge tests. LiFePO4-C/Li battery with 4.75 wt% PSS displays discharge capacity of 128 mAh g-1 at room temperature that is considerably higher than pure LiFePO4/Li battery ( 113.48 mAhg-1).