Investigação de sistemas fortemente correlacionados aplicados à eletroquímica

Abstract

The understanding of materials used in electrochemical processes, especially those based on transition-metal oxides, requires an accurate description of electronic correlation effects. These materials present partially filled d and f orbitals and exhibit phenomena that challenge conventional electronic-structure models, such as Band Theory and the local or semilocal DFT functionals (LDA/GGA). In this work, the fundamental principles governing strongly correlated systems are investigated, including Mott insulators, charge-transfer insulators, and Peierls insulators, as well as the main theoretical models developed to describe them, such as the Hubbard model and its extensions. Next, the limitations of traditional first-principles methods in predicting electronic and energetic properties of correlated materials are discussed, highlighting the importance of improved methodologies such as DFT+U, DFT+U+V, hybrid functionals (HSE06), and DFT+DMFT. The application of these methods is illustrated through recent case studies involving cationic materials used in lithium-ion batteries, in which the inclusion of local and non-local electronic correlations proves essential for the accurate prediction of intercalation voltages, oxidation states, and structural characteristics. The discussed results show that conventional approaches tend to fail in strongly correlated systems, while advanced methods offer significantly more realistic descriptions that are consistent with experimental observations. Thus, this monograph reinforces the importance of electronic correlations in modern electrochemistry and highlights the role of advanced electronic-structure methods in the rational development of high-performance electroactive materials.