Abstract: Disclosed is an alkali-metal-ion secondary battery including a cathode material, an electrolyte, a separator, and an anode material, in which each of the cathode material and the anode material includes an electrically conductive carbon allotrope and an alkali metal compound, the weights or composition ratios of the electrically conductive carbon allotropes contained in the cathode material and the anode material are different from each other, and the weights or composition ratios of the alkali metal compounds contained in the cathode material and the anode material are different from each other.

Abstract: A graphite exfoliation system includes a first graphite exfoliation apparatus including a first inlet, a first pressurizing unit, a first high-pressure unit and a first extraction unit, a second graphite exfoliation apparatus including a second inlet, a second pressurizing unit, a second high-pressure unit and a second extraction unit, and a third graphite exfoliation apparatus including a third inlet, a third pressurizing unit, a third high-pressure unit and a third extraction unit, so as to allow the graphite powder to pass through an exfoliation process at least three times while gradually decreasing the inner cross-sectional areas of passages of the respective high-pressure units of the first, second and third graphite exfoliation apparatuses or maintaining the inner cross-sectional areas of the passages of the respective high-pressure units to be at least equal.