What component is necessary in an electrolytic cell but not in a voltaic cell?

An electrolytic cell requires an external power source to drive the non-spontaneous chemical reactions, while a voltaic cell generates electrical energy from spontaneous reactions. This external power supply is necessary for the electrolytic process, as it forces the flow of electrons and facilitates the electrolysis of the electrolyte. In contrast, a voltaic cell relies on the chemical energy produced by the reactions occurring within the cell itself to generate electricity.