Electrochemical intercalation of ionic species of tetrabutylammonium perchlorate on graphite electrodes. A potential dual-intercalation battery system

A study is conducted on the intercalation of ionic species of tetrabutylammonium perchlorate in propylene carbonate medium in order to develop a dual-intercalation battery system. Cyclic voltammetry, current-time transients. X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements are carried out to establish and evaluate the efficiency of intercalation of perchlorate anion and tetrabutylammonium cation. Dual intercalation for both the ionic species can indeed be achieved from the same solvent. Compared with high purity commercial graphite material, a graphite polypropylene composite electrode containing 20 wt.% polypropylene as a binder (CPP) is found to be more efficient. The intercalation/de-intercalation efficiency increases with electrolyte concentration and reaches up to 55% on this CPP material for both the ionic species. XRD data also confirm the intercalation of both the ions. SEM studies indicate stronger graphite exfoliation during cationic intercalation. Cycling efficiency remains fairly high, however, as long as the intercalation/de-intercalation time does not exceed 10 min.