EVALUATION OF THE CHEMICAL COMPOSITION OF THE ACTIVE CATHODE MATERIAL SPENT LI-ION BATTERIES BY ICP OES USING CITRIC ACID AS LEACHING AGENT

The significant use of Li-ion batteries to supply a technological need for energy storage generates a large amount of solid waste. When disposed of improperly they can become potential environmental risks and waste of natural resources due to their chemical composition. With the advancement of technology other elements, in addition to Co and Li, are being employed in the composition of the active cathode materials for improvements in energy performance and low cost production [1, 2]. In this work, Al, Cr, Cu, Ga, Li, Mg, Mn, Ni, Ti and Zn were determined in active material of the cathode of spent Li-ion batteries from mobile phones by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) to evaluate the elemental composition over the years. An environmentally friendly leaching process using organic acid was employed to solubilize the metals. The experimental conditions used for leaching were as follows: 2.0 mol L−1 of citric acid, temperature of 80 °C, time of 2 hours, a liquid-solid ratio of 20 g L-1, and 0.25 mol L-1 of H2O2 30 % (v/v) [3]. The leaching solutions from samples were carried out by ICP OES (Optima 7000, PerkinElmer). For the determination of metals by ICP OES was employed analytical curves using the solutions obtained from diluting multi and mono elementary standard solution with citric acid 2.0 mol L-1 diluited 500 times for Co, Li, Mn and Ni, 10 times for Al, Cu, Cr, Mg and Ti, and analyzed directly for Ga an Zn using Y (0.5 mg L-1) as internal standard. The concentrations of the elements obtained demonstrated that the old battery presents high content of Co and Li like expected, while the recent batteries uses a mixture of elements like Co, Li, Mn, Zn and others elements in a very low concentration constituting mixed oxides cheaper to industrial production.