Supercharging device for an internal combustion engine having an intake side and having an exhaust-gas side and having an intake tract arranged on the intake side and having an exhaust-gas tract arranged on the exhaust-gas side, which supercharging device has - an exhaust-gas turbocharger having an exhaust-gas turbine, which is arranged in the exhaust-gas tract, and a fresh-air compressor having a low-pressure side and a high-pressure side, which is arranged in the intake tract; - a fresh-air supply device to which the fresh-air compressor is connected on its low-pressure side, and - a charge-air feed line which connects the high-pressure side of the fresh-air compressor to the intake side of the internal combustion engine for the purposes of conducting a charge-air mass flow generated by the fresh-air compressor, and - a recuperation charger which has a compressor-turbine with a high-pressure side and a low-pressure side and which has an electromechanical motor-generator coupled to said compressor-turbine, characterized in that - the compressor-turbine is coupled by means of line connections (11a, 11b, 11e) and valve devices (15a - 15e) to the charge-air feed line in such a way that the low-pressure side of the compressor-turbine is connected, at least via a low-pressure branch line and a first valve device, to the charge-air feed line at a first charge-air branching point, and the high-pressure side of the compressor-turbine is connected, at least via a high-pressure branch line and a second valve device, to the charge-air feed line at a second charge-air branching point downstream of the first charge-air branching point, and the charge-air feed line can be shut off between the first charge-air branching point and the second charge-air branching point by means of the first or second valve device (15a, 15b) or at least one further valve device, such that the recuperation charger is operable in a manner dependent on the settings of the valve devices (15a - 15e), at least firstly in a booster operating mode, in a manner driven by the motor-generator, as a compressor for increasing the pressure of the charge-air mass flow in the charge-air line, and secondly in a recuperation operating mode, in a manner driven by the charge-air mass flow, as a turbine for energy recovery by means of the motor-generator. - an exhaust-gas turbocharger having an exhaust-gas turbine, which is arranged in the exhaust-gas tract, and a fresh-air compressor having a low-pressure side and a high-pressure side, which is arranged in the intake tract; - a fresh-air supply device to which the fresh-air compressor is connected on its low-pressure side, and - a charge-air feed line which connects the high-pressure side of the fresh-air compressor to the intake side of the internal combustion engine for the purposes of conducting a charge-air mass flow generated by the fresh-air compressor, and - a recuperation charger which has a compressor-turbine with a high-pressure side and a low-pressure side and which has an electromechanical motor-generator coupled to said compressor-turbine, - the compressor-turbine is coupled by means of line connections (11a, 11b, 11e) and valve devices (15a - 15e) to the charge-air feed line in such a way