A comparative study of different binders and their effects on electrochemical properties of LiMn2O4 cathode in lithium ion batteries

Physical and chemical properties of poly(vinylidene fluoride) (PVDF), sodium carboxymethyl cellulose (CMC) and polyacrylic acid (PAA) binders are investigated in this paper, including functional group analysis, crystallinity and thermal properties. Then LiMn2O4 cathodes with four different binder systems (PAA binders/NMP solvent, PVDF binders/NMP solvent, PAA binders/H2O solvent and CMC binders/H2O solvent) are prepared, and their adhesion strengths, swelling properties, morphologies and electrochemical properties are studied. The results show that the LiMn2O4 cathode with PAA/NMP system displays the best cycle performances at both 25 °C and 55 °C among these four cathodes; the better capacity retention for LiMn2O4 cathode with PAA/NMP system is related to strong binding ability, appropriate swelling property and homogeneous distribution of particles inner the electrode.