Due to the current widespread use of lithium-ion batteries in a range of applications, significant amounts of metal-containing waste materials are generated. Typically, the recycling of transition metals from lithium-ion batteries involves leaching of Co2+ and Li+ from the LiCoO2 anode and the electrolyte (e.g., LiPF6, LiBF4). Thus, we herein examined the application of slug flow to the extraction of Co2+ and Li+ from an aqueous solution into an organic (cyclohexane) phase containing di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extraction reagent. The extraction equilibrium and extraction rate were then investigated to design a novel extraction process. In addition, a microchannel was employed to extract the Co2+ and Li+ ions from the aqueous phase. We found that the D2EHPA-Na solution (prepared from the partial exchange of H+ from D2EHPA with Na) was effective for extracting Co2+ and, at a mole fraction of D2EHPANa >10%, complete Co2+ extraction from the aqueous phase was achieved. In addition, the presence of co-existing ions did not significantly affect the extraction behavior of Co2+ and Li+. Furthermore, the volumetric mass transfer coefficients (k(L)a) of Co2+ and Li+ exhibited the same order as those previously reported for other slug flow extraction systems. Finally, the ion concentration and selectivity were successfully simulated using the k(L)a values and the simulation results were in good agreement with experimental data. Such simulation of the Co2+ yield and purity is essential for selecting optimal process design conditions.