Cobalt (Co) and lithium (Li) were extracted from pure LiCoO2 powders and actual cathode material powders from the spent lithium-ion batteries (LIBs) after l-ascorbic acid dissolution via a mechanical activation process. The influences of activation time and rotation speed on the leaching were discussed. The mechanism of the improved leaching yield was proposed based on the characterization analysis including X-ray diffraction, scanning electron microscope, BET-specific surface area and particle size analyzer. The reduced particle size, increased specific surface area of activated samples, destroyed crystal structure and amorphous state of LiCoO2 contributed to the improved leaching efficiencies of Co and Li. With the activated process, about 99% Co and 100% Li were extracted from actual spent LIBs after 60-min grinding at 500 rpm with mild conditions. This effective process would be of great importance for recovering valuable metals from the spent LIBs at room temperature.