Electrochemical characterization of LiFePO4/poly (sodium 4-styrenesulfonate)-multi walled carbon nanotube composite cathode material for lithium ion batteries

LiFePO4 is a promising cathode material for lithium ion batteries and is prepared by a hydrothermal method. However, its practical application is limited due to its poor conductivity. In order to improve the electronic conductivity, we added poly (sodium 4-styrenesulfonate) (PSS) and multi walled carbon nanotube (MWCNT) in LiFePO4. In the results, PSS stacks and forms a layer about 3-6 nm around the surface of LiFePO4 particles. MWCNT provides pathways for electron transport. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic discharge testing results indicate that LiFePO4/PSS-MWCNT composite exhibits higher discharge capacity than pure LiFePO4. LiFePO4/PSS(2.5%)-MWCNT(2.5%) shows the best discharge capacity of 144 mAh g−1 at 2nd cycle, and high electronic conductivity of 6.3 × 10−3 S cm−1.