A method for preparing a cylindrical, alkali metal-ion hybrid supercapacitor, comprising at least one cylindrical coiled element and an outer enclosure containing a main body intended to receive said cylindrical coiled element, said method comprising at least the following steps: i) preparing a cylindrical coiled element centered on an axis X-X comprising at least one positive electrode, at least one negative electrode and at least one separator interposed between the positive and negative electrodes, the positive and negative electrodes and the separator being wound together in turns around said axis X-X, the cylindrical coiled element having a central free volume along the axis X-X, with the understanding that: * the positive electrode comprises at least one positive electrode active material capable of interposing and de-interposing ions of an alkali metal M1 and/or capable of adsorbing and desorbing ions of an alkali metal M1, said positive electrode being deposited on a positive electrode current collector, and * said negative electrode comprises at least one negative electrode active material capable of interposing and de-interposing ions of an alkali metal M1, said negative electrode being deposited on a negative electrode current collector, ii) inserting the cylindrical coiled element into a main body of an outer enclosure intended to receive said cylindrical coiled element, iii) impregnating the cylindrical coiled element with a nonaqueous liquid electrolyte comprising a salt of said alkali metal M1 and an organic solvent, said method being characterized in that it further comprises: iv) inserting a solid mass comprising said alkali metal M1 into the central free volume of the cylindrical coiled element, before or after step iii), v) electrically connecting the solid mass with the negative electrode so as to obtain a short-circuit and to interpose ions of said alkali metal M1 into the negative electrode of the cylindrical coiled element, vi) removing the solid mass from the cylindrical coiled element, and vii) hermetically sealing the main body of the outer enclosure, in order to obtain the cylindrical, alkali metal-ion hybrid supercapacitor. i) preparing a cylindrical coiled element centered on an axis X-X comprising at least one positive electrode, at least one negative electrode and at least one separator interposed between the positive and negative electrodes, the positive and negative electrodes and the separator being wound together in turns around said axis X-X, the cylindrical coiled element having a central free volume along the axis X-X, with the understanding that: * the positive electrode comprises at least one positive electrode active material capable of interposing and de-interposing ions of an alkali metal M1 and/or capable of adsorbing and desorbing ions of an alkali metal M1, said positive electrode being deposited on a positive electrode current collector, and * said negative electrode comprises at least one negative electrode active material capable of interposing and de-interposing ions of an alkali metal M1, said negative electrode being deposited on a negative electrode current collector, * the positive electrode comprises at least one positive electrode active material capable of interposing and de-interposing ions of an alkali metal M1 and/or capable of adsorbing and desorbing ions of an alkali metal M1, said positive electrode being deposited on a positive electrode current collector, and * said negative electrode comprises at least one negative electrode active material capable of interposing and de-interposing ions of an alkali metal M1, said negative electrode being deposited on a negative electrode current collector, ii) inserting the cylindrical coiled element into a main body of an outer enclosure intended to receive said cylindrical coiled element, iii) impregnating the cylindrical coiled element with a nonaqueous liquid electrolyte comprising a salt of said alkali metal M1 and an organic solvent, iv) inserting a solid mass comprising said alkali metal M1 into the central free volume of the cylindrical coiled element, before or after step iii), v) electrically connecting the solid mass with the negative electrode so as to obtain a short-circuit and to interpose ions of said alkali metal M1 into the negative electrode of the cylindrical coiled element, vi) removing the solid mass from the cylindrical coiled element, and vii) hermetically sealing the main body of the outer enclosure, in order to obtain the cylindrical, alkali metal-ion hybrid supercapacitor.