This study presents a new method for selectively extracting lithium (Li) from pyrolyzed lithium-ion batteries (LIBs) black mass (BM) using a novel caustic (NaOH) leaching process. The efficiency of the NaOH leaching has been evaluated by response surface methodology (RSM), and the effects of leaching parameters on Li leaching efficiency (LE) and selectivity have been discussed in terms of leaching mechanism based on thermodynamics and kinetics studies. The results show that caustic leaching has excellent selectivity towards Li with no detectable leaching for nickel (Ni), manganese (Mn), cobalt (Co), and copper (Cu), LE up to ∼81 % Li. However, caustic leaching coextracts aluminium with Li. Further, Li is recovered from leach solution as lithium hydroxide (LiOH) using evaporative crystallization or lithium carbonate (Li2CO3) with Na2CO3 addition and CO2 injection. Li2CO3 recovered via CO2 injection has the highest purity at ∼93 %, surpassing the Li2CO3 purity levels obtained through precipitation with Na2CO3 (∼82 %) and LiOH (∼21 %) retrieved via evaporative crystallization.