Abstract: A method for prelithiating a soft carbon negative electrode includes the steps of: disposing the soft carbon negative electrode and a lithium metal piece spaced apart from each other with a lithium-containing electrolyte present therebetween; prelithiating the soft carbon negative electrode at a first constant C-rate until a voltage thereof is reduced to a first predetermined voltage not greater than 0.3 V vs. Li/Li+, the first constant C-rate being not greater than 5 C; prelithiating the soft carbon negative electrode at a second constant C-rate until the voltage thereof is reduced to a second predetermined voltage lower than the first predetermined voltage, the second constant C-rate being not greater than 0.2 C and being less than the first constant C-rate; and prelithiating the soft carbon negative electrode at a prelithiation constant voltage which is not greater than the second predetermined voltage, thereby completing prelithiation of the soft carbon negative electrode.