Recent advances in the electric vehicle technology and industry caused a substantial growth of the LIB market, which increased the demand for the key resources such as lithium, nickel, and cobalt. There have been significant efforts to recycle spent LIB electrodes in order to secure the supply chains of the resources and make LIB production and utilization cycles more sustainable. In this study, we developed processes for the selective recovery of lithium and nickel from the black mass produced from spent LIBs. By using HCl solution at the optimized conditions, leaching of lithium and nickel from the black mass could be performed with high selectivity over other metallic species. A flow-type integrated electrochemical system was prepared by using lithium nickel manganese oxide (LiNi0.5Mn1.5O4) and titanium foil electrodes for lithium electrosorption and nickel electrodeposition, respectively. By cyclic operation of the electrochemical process, both lithium and nickel could be recovered effectively with reasonable energetics and stability, corroborating the capability of the integrated system.