Effect of solvents and solvent mixtures on intercalation/de-intercalation behaviour of Li+ and ClO4− ions in polypropylene–graphite composite electrodes

The intercalation of Li+ and ClO4− ions in polypropylene–graphite composite electrodes in different single solvents and 1:1 binary solvent mixtures is studied by means of cyclic voltammetry and scanning electron microscopy. The intercalation/de-intercalation efficiency as a potential dual-intercalation battery electrode for cationic intercalation (positive electrode) is found to be generally lower than that for anionic intercalation in most of the solvents. 1:1 solvent mixtures do not enhance intercalation/de-intercalation efficiency significantly beyond the values found in a single solvent. The mixed-solvent system leads, however, to less co-solvent intercalation and graphite exfoliation, and hence better cycle-life as a potential battery electrode.