A selective dissolution process to recover lithium from cathode materials by oxalic acid was investigated. The chemical reaction responsible for dissolution was identified, and the effects of operating parameters including temperature, acid concentration, as well as solid-to-liquid feed ratio on lithium recovery were studied using LiNi0.5Mn0.3Co0.2O2 (NMC-532) as the base case cathode materials, leading to a lithium recovery of 96.3% from cathode materials. However, 2.16% of manganese was also dissolved with lithium. An integrated process based on chemical and antisolvent precipitation was synthesized to separate and recover manganese and lithium with high recovery and high purity from the liquid after dissolution. This process was also shown to work on other cathode materials including LiNixMnyCo1-x-yO2 of various metal ratios, LiMn2O4 and LiCo0.95Mn0.05O2.