Recovery of critical metals from spent Li-ion batteries: Sequential leaching, precipitation, and cobalt–nickel separation using Cyphos IL104

•Li was selectively leached in H2O from NCM cathode and precipitated using Na2CO3.•>98 % Co, Ni, and Mn leached in 3.0 mol·L−1 HCl at 5 % pulp density and 90 °C.•MnO2 precipitated using KMnO4 at 1.25-fold higher molar ratio than stoichiometric.•Co separated from Ni by Cyphos IL104 at pHeq 5.4 was stripped in H2SO4 solution.•Basic nickel carbonate was precipitated at Ni2+:CO32− ratio 2.5, pH 10.8, and 50 °C.