The present invention relates to a carbonaceous material having a silicon element content of less than 200 ppm, a powder conductivity of 10.0 to 22.0 S/cm, a total amount of surface functional groups of 0.22 to 0.36 meq/g, and a pore volume of 0.10 to 0.20 cm.sup.3/g in terms of pores having a pore size of not less than 4 nm as measured by a BJH method.

The present invention relates to a carbonaceous material having a silicon element content of less than 200 ppm, a powder conductivity of 10.0 to 22.0 S/cm, a total amount of surface functional groups of 0.22 to 0.36 meq/g, and a pore volume of 0.10 to 0.20 cm.sup.3/g in terms of pores having a pore size of not less than 4 nm as measured by a BJH method.

A boron-sulfur-codoped porous carbon material and a preparation method is disclosed. The boron-sulfur-codoped porous carbon material includes a porous carbon, and B and S doped in the surface and pores of the porous carbon; where B has a doping content of 5.56 wt.% to 7.85 wt.%, and S has a doping content of 0.90 wt.% to 1.55 wt.%. Test results of examples show that the boron-sulfur-codoped porous carbon material has high doping contents of B and S, and abundant pores; in a three-electrode system, the material shows a maximum specific capacitance of 168 F.Math.g.sup.- .sup.1 to 290.7 F.Math.g.sup.-1 at 0.5 A.Math.g.sup.-1; after the material is assembled into a symmetrical supercapacitor, the supercapacitor has an ultra-high energy density of 11.3 Wh.Math.kg.sup.-1 to 16.65 Wh.Math.kg.sup.-1 in a neutral electrolyte system, and has a capacitance retention rate of 97.09% to 100.67% after 10,000 life tests.

A boron-sulfur-codoped porous carbon material and a preparation method is disclosed. The boron-sulfur-codoped porous carbon material includes a porous carbon, and B and S doped in the surface and pores of the porous carbon; where B has a doping content of 5.56 wt.% to 7.85 wt.%, and S has a doping content of 0.90 wt.% to 1.55 wt.%. Test results of examples show that the boron-sulfur-codoped porous carbon material has high doping contents of B and S, and abundant pores; in a three-electrode system, the material shows a maximum specific capacitance of 168 F.Math.g.sup.- .sup.1 to 290.7 F.Math.g.sup.-1 at 0.5 A.Math.g.sup.-1; after the material is assembled into a symmetrical supercapacitor, the supercapacitor has an ultra-high energy density of 11.3 Wh.Math.kg.sup.-1 to 16.65 Wh.Math.kg.sup.-1 in a neutral electrolyte system, and has a capacitance retention rate of 97.09% to 100.67% after 10,000 life tests.

Disclosed here is a method for producing a graphene macro-assembly (GMA)-fullerene composite, comprising providing a mixture of graphene oxide and water, adding a hydroxylated fullerene to the mixture, and forming a gel of the hydroxylated fullerene and the mixture. Also described are a GMA-fullerene composite produced, an electrode comprising the GMA-fullerene composite, and a supercapacitor comprising the electrode.

Disclosed here is a method for producing a graphene macro-assembly (GMA)-fullerene composite, comprising providing a mixture of graphene oxide and water, adding a hydroxylated fullerene to the mixture, and forming a gel of the hydroxylated fullerene and the mixture. Also described are a GMA-fullerene composite produced, an electrode comprising the GMA-fullerene composite, and a supercapacitor comprising the electrode.

There is disclosed a process of producing a hybrid super-capacitor (HSC) electrode, the process comprising performing nitridation-induced in situ coupling of Ni—Co.sub.4N nanoparticles in an N-doped carbon matrix, wherein the resultant hybrid super-capacitor (HSC) electrode is a Ni—Co.sub.4N@NC electrode. The resultant hybrid super-capacitor (HSC) electrode is a self-supported metal nitride coordinated with N-doped carbon, wherein the nitridation-induced in situ coupling is performed via a facile pyrolysis of layered Ni—Co hydroxide decorated on polyaniline (PANI) nanotubes on the basis of a carbon cloth (CC). Also disclosed is a hybrid supercapacitor cell assembled by employing Ni—Co.sub.4N-2@NC as a positive electrode and AC as a negative electrode with a PVA (poly vinyl alcohol)/KOH as a gel electrolyte.

There is disclosed a process of producing a hybrid super-capacitor (HSC) electrode, the process comprising performing nitridation-induced in situ coupling of Ni—Co.sub.4N nanoparticles in an N-doped carbon matrix, wherein the resultant hybrid super-capacitor (HSC) electrode is a Ni—Co.sub.4N@NC electrode. The resultant hybrid super-capacitor (HSC) electrode is a self-supported metal nitride coordinated with N-doped carbon, wherein the nitridation-induced in situ coupling is performed via a facile pyrolysis of layered Ni—Co hydroxide decorated on polyaniline (PANI) nanotubes on the basis of a carbon cloth (CC). Also disclosed is a hybrid supercapacitor cell assembled by employing Ni—Co.sub.4N-2@NC as a positive electrode and AC as a negative electrode with a PVA (poly vinyl alcohol)/KOH as a gel electrolyte.

An electrolytic solution for an electrochemical device a solvent, an ionic substance, and an additive agent, the additive agent containing α-methyl-γ-butyrolactone and δ-valerolactone.

An electrolytic solution for an electrochemical device a solvent, an ionic substance, and an additive agent, the additive agent containing α-methyl-γ-butyrolactone and δ-valerolactone.