Reciclagem do cátodo de bateria de íons de lítio do tipo LiFePO4 (LFP) e aplicação do material reciclado como pseudocapacitor

• Ano de defesa: 2024
• Autor(a) principal: Querubino, Renan Bobbio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Química; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Química
• Palavras-chave em Português: Sustentabilidade; Reciclagem; Bateria; Química
• Link de acesso: http://repositorio.ufes.br/handle/10/18137

Recycling lithium-ion batteries (LIBs) is an effective method of solid waste treatment and is crucial for the recovery of scarce, high-value metals that are of great technological importance. In this work, spent LIBs from electric vehicles were recycled through hydrometallurgical and pyrometallurgical processes, utilizing both citric acid and hydrogen peroxide leaching and alkaline leaching. The exhausted cathode material was characterized using X-ray Diffraction (XRD), Raman Spectroscopy, Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM), and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), identifying LiFePO4, Fe2O3, and FePO4 as the primary phases in its composition, along with the secondary phases Fe(OH)3 and Fe2(PO4)O. The hydrometallurgical recycling process, performed by acidic leaching of the cathode with 1.0 mol L−1 citric acid and hydrogen peroxide, showed low selectivity for the leaching of lithium and iron. In contrast, alkaline leaching proved to be more effective in recovering lithium and preserving the structural components of the material, such as LiFePO4, while not leaching iron, resulting in a more efficient separation of battery constituents. From the residue of alkaline leaching, lithium ferrite (β-LiFe5O8) was synthesized. Structural and morphological characterizations of lithium ferrite, performed by XRD, Raman Spectroscopy, and SEM, indicated the formation of a disordered crystalline phase with agglomerated grain morphology, with particles of undefined size. The electrochemical evaluation of the recycled material as a pseudocapacitor was promising. The recycled material exhibited a pseudocapacitive profile with a maximum specific capacitance of 7.6 F g−1 and capacitance retention of 82% over 250 cycles, at a charge-discharge current density of 0.7 A g−1. The pseudocapacitive profile of this material included contributions from electric double-layer charge storage and Faradaic processes. This study demonstrates the feasibility of recycling spent lithium-ion battery materials, transforming them into high-value-added materials with promising technological applications, contributing to sustainability and the circular economy.