Abstract:Complex waste mixed cathode materials have problems of low leaching rate, high cost and long metal separation process from acid leaching solution. These materials were leached by mixed acid precipitation method with sulfuric acid as leaching agent and H2O2 as reductant. NCM622 was synthesized by carbonate coprecipitation method, its microstructure was characterized and its electrochemical performance was measured. The results show that leaching rate of Li, Ni, Co and Mn is 98.79%, 97.05%, 96.45% and 96.31%, respectively under the optimum conditions including sulfuric acid concentration of 2.5 mol/L, H2O2 dosage of 0.6 mol/L, stirring rate of 400 r/min, time of 30 min, and temperature of 80 ℃. XRD analysis shows that regenerated NCM622 has no impurity peak and has typical α-NaFeO2 layered structure. SEM shows NCM622 particles are uniform in size and less agglomerated. Electrochemical test shows that specific discharge capacity of first cycle is 152.87 mAh/g at 1C rate, and capacity retention rate is 91.35% after 100 cycles.