Sustainable preparation of Li(FeM)PO4/C from converter sludge and its electrochemical performance as a cathode material for lithium ion batteries

Li(FeM)PO4/C (M = Mg, Al, Zn and Mn) cathode material for lithium ion batteries is prepared by using converter sludge as a raw material through a sustainable wet chemistry method. The valuable elements (Fe, Mg, Al, Zn and Mn) are recovered from converter sludge through acidolysis process, and used as source materials of Fe and dopants for preparing Li(FeM)PO4/C. XRD and SEM analyses show that the obtained Li(FeM)PO4/C delivers single olivine-type phase with higher crystallinity, and presents a fine particle size less than 100 nm and a homogeneous elemental distribution in its contexture. Especially, Li(FeM)PO4/C prepared from the sludge gives outstanding capacity of 157, 154, 143, 127 and 118 mA h g−1 at a current density of 15, 75, 150, 300 and 750 mA g−1, respectively, and exhibits excellent cycling performance. The results demonstrate that a novel route to synthesize Li(FeM)PO4/C cathode material for lithium ion batteries by utilizing converter sludge as a abundant and inexpensive source of iron and dopants has been proposed.