Abstract
A preparation method of a soft carbon material for a high-voltage supercapacitor is provided. The method includes: a soft carbon material providing step of providing a soft carbon material, wherein the soft carbon material comprises characteristics of: (A) a first carbon layer spacing of more than 0.345 nm and less than 0.360 nm; (B) a crystal plane (002) having a crystal plane size (Lc) of less than 6 nm; (C) a crystal plane (101) having a crystal plane size (La) of less than 6 nm; (D) an intensity ratio (I(002)/I(101)) of less than 60 for a material structure obtained from XRD analysis at the crystal plane (002) and the crystal plane (101); an alkali activation processing step of performing alkali activation processing on the soft carbon material using an alkali active agent to obtain a first processed carbon material; and an electrochemical activation processing step of performing electrochemical activation processing on the first processed carbon material using an electrolyte to obtain the soft carbon material for a high-voltage supercapacitor. The soft carbon material for a high-voltage supercapacitor has, similar to that of an electric double layer (EDLC), a symmetrical capacitance charging and discharging curve at a low specific surface area.