Síntese de um material multifuncional como uma forma de reciclagem verde de baterias de íons de lítio exauridas

Abstract

The green recycling of spent lithium-ion batteries has shown to be of great importance in the conservation of the environment, preservation of mineral resources and the development of cheaper metallic materials. An assay of the cathode leaching parameters of spent batteries was carried out via ICP-OES. The cathodic active material from the lithium-ion batteries was leached with lactic acid. From the leachate, recycled materials were synthesized by selective precipitation and calcination (4.5 h at 450 °C). The composition and characterization of the microstructure of the recycled material was confirmed by X-ray diffraction, Raman spectroscopy, SEM and thermal analysis. Recycled metallic materials were evaluated as pseudocapacitors and electrochemical sensors using cyclic voltammetry, linear scanning and charge and discharge cycles. The electrochemical reproducibility of the material as a pseudocapacitor was verified by cyclic voltammetry. The recycled material presented 11.63 F g-1 of specific capacitance, after a thousand cycles of galvanostatic charge and discharge at currents of 3 mA g-1. By linear scanning voltammetry it was verified the oxidation of ascorbic acid at 0.10 V and the growth of the anodic peak current with the increase of its concentration. The analytical curve of the sensor showed an R2 of 0.9915, sensitivity of 0.0498 ± 0.0023 µA mol L-1 and LD of 0.0245 mol L-1 in the concentration range of 0.166 to 1.0 mmol L-1. The modified electrode was characterized by SEM before and after its cycling. As a photocatalyst, the recycled material showed 61.47% efficiency for the decolorization of methylene blue after 120 min, in the presence of UV radiation and H2O2. The reaction was determined to be pseudo-first order and had a k of 7,95 ∙ 10−3 min-1. The recycled material presented a multifunctionality in its applications, being used as raw material for the development of pseudocapacitors, non-enzymatic electrochemical sensors and photocatalysts.