A process for the preparation of a hybrid supercapacitor, said process comprising at least one stage of assembling a negative electrode based on at least one nonporous carbon-based material and a positive electrode based on at least one porous carbon-based material, said electrodes being separated from one another by means of a separator impregnated with a liquid electrolyte comprising at least one lithium salt in solution in at least one solvent, then at least one first stage of charging, said process being characterized in that: a) the concentration of ionic lithium in the liquid electrolyte before the first charging stage is greater than or equal to 1.6 mol/1, b) the lithium salt of the liquid electrolyte comprises at least 50% by weight of a lithium salt chosen from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and its derivatives, such as lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(pentafluoroethylsulfonyl)imide (LiBETI); c) the solvent of the liquid electrolyte comprises at least 80% by volume of a solvent chosen from cyclic alkyl carbonates, chosen from ethylene carbonate and propylene carbonate, acyclic alkyl carbonates, chosen from dimethyl carbonate, diethyl carbonate and methyl isopropyl carbonate (MiPC), lactones, esters, oxalanes and their mixtures, it being understood that said solvent comprises at least 20% by volume of ethylene carbonate; d) the porous carbon-based material of the positive electrode is chosen from materials in which the mean dimension of the pores is greater than 0.7 nm and which have a specific surface of greater than 700 m 2 /g approximately; e) the nonporous carbon-based material of the negative electrode is chosen from materials which are capable of inserting the lithium ions and which have a specific surface of less than or equal to 150 m 2 /g; f) after the assembling stage, the charging of said supercapacitor is carried out in several successive charging stages up to a maximum voltage (U max) of between 4 and 5 volts and at a current density varying from 10 mA/g to 400 mA/g, each charging stage being separated from the following charging stage by an intermediate stage of self-discharging or discharging at a current density of less than 5 mA/g. a) the concentration of ionic lithium in the liquid electrolyte before the first charging stage is greater than or equal to 1.6 mol/1, b) the lithium salt of the liquid electrolyte comprises at least 50% by weight of a lithium salt chosen from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and its derivatives, such as lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(pentafluoroethylsulfonyl)imide (LiBETI); c) the solvent of the liquid electrolyte comprises at least 80% by volume of a solvent chosen from cyclic alkyl carbonates, chosen from ethylene carbonate and propylene carbonate, acyclic alkyl carbonates, chosen from dimethyl carbonate, diethyl carbonate and methyl isopropyl carbonate (MiPC), lactones, esters, oxalanes and their mixtures, it being understood that said solvent comprises at least 20% by volume of ethylene carbonate; d) the porous carbon-based material of the positive electrode is chosen from materials in which the mean dimension of the pores is greater than 0.7 nm and which have a specific surface of greater than 700 m 2 /g approximately; e) the nonporous carbon-based material of the negative electrode is chosen from materials which are capable of inserting the lithium ions and which have a specific surface of less than or equal to 150 m 2 /g; f) after the assembling stage, the charging of said supercapacitor is carried out in several successive charging stages up to a maximum voltage (U max) of between 4 and 5 volts and at a current density varying from 10 mA/g to 400 mA/g, each charging stage being separated from the following charging stage by an intermediate stage of self-discharging or discharging at a current density of less than 5 mA/g.