Chlorinated graphite as positive electrode for aluminium-ion batteries with 1-ethyl-3-methylimidazolium chloride/aluminium chloride electrolyte

The article defines the dependence type of the cathode polarization of an aluminum-ion battery based on chlorinated graphite of the initial EC-02 type in a low-temperature melt of aluminum chloride with 1-ethyl-3-methylimidazole chloride on the geometric characteristics of the electrode and the current density. It is determined that for the chlorinated graphite material the polarization values are slightly reduced compared to the initial non-chlorinated graphite of the same brand in a similar melt and are 25–50 mV at 1 mA/cm². The dependence of polarization on the current density does not have a break between the values of 1 and 1.2 mA/cm², observed for initial graphite, which characterizes the maximum rate of the current-generating reaction, which means an increase in the rate of the main process on the chlorinated graphite. Using a reference experiment on a glassy carbon electrode, the surficial density of chloroaluminate complexes intercalation sites was estimated as about 15%. Accordingly, the maximum degree of intercalation for such materials is 6. Since graphite chlorination does not lead to distortions geometric parameters of its interlayer gaps, the sorption density of chloroaluminate ions is found to increase after chlorination; in the case of non-chlorinated graphite, the degree of intercalation varies with current density from 9 to 18.