Presentation Title: Durable Ni-rich layered cathodes enabled by niobium doping

Abstract: 

     The drive toward higher energy density in lithium-ion batteries has accelerated the development of Ni-rich layered oxide cathodes, particularly materials with Ni contents above 90%. Their practical application, however, remains limited by rapid degradation involving structural instability, surface reconstruction, interfacial side reactions, and particle cracking during cycling. These processes are strongly linked to the H2↔H3 phase transition at high states of charge and become more severe with increasing Ni content. In this work, the Ni-rich layered cathode Li_1.02Ni_0.905Co_0.043Al_0.052O₂ was modified through controlled niobium incorporation to improve structural and electrochemical stability. Nb doping in the range of 0.1–1 mol.% was systematically investigated in terms of crystal structure, particle morphology, surface chemistry, and electrochemical behavior. An optimum Nb concentration of approximately 0.5 mol.% was identified, providing improved cycling stability and mitigation of structural changes associated with the H2↔H3 transition. Niobium modification also influenced particle morphology and interfacial stability. In addition, treatment with ammonium niobium oxalate promoted removal of residual lithium species and formation of a thin LiNbO₃-based surface layer, further stabilizing the cathode–electrolyte interface. To complement the experimental analysis, a transformer-based model was applied to cycling data to predict capacity degradation and discharge-curve evolution. The model provides a data-driven perspective on the stabilization induced by Nb modification. Overall, the combined structural, morphological, interfacial, and electrochemical results demonstrate that niobium offers a multifaceted route to improving the durability of highly Ni-rich layered cathodes, while transformer-based prediction provides an additional tool for linking materials modification with long-term electrochemical behavior. 

Biography: 

   Konrad Świerczek - full professor of technical sciences (2019), currently the head of the Department of Hydrogen Energy, Faculty of Energy and Fuels, AGH University of Krakow and a member of AGH University Council (from 2025). Deputy Dean of the Faculty of Energy and Fuels (2016-2020 and 2020-2024 terms). Member of the Coordination Council for the Hydrogen Economy (from 2022). Author and co-author of over 210 papers in journals from the Journal Citation Reports list (total IF > 1200). Scientific interests include issues in the field of solid state electrochemistry, materials science and energy. Research works concern: new generation of electrode materials and solid electrolytes for solid oxide fuel cells and high temperature electrolysers; electrode materials for lithium and post-lithium-ion cells, including high-entropy compounds; oxygen storage materials; materials with mixed ionic-electronic conductivity for the construction of ceramic membranes. The most important scientific achievement is related to the demonstration and understanding the correlations between the chemical and phase composition, crystal structure, microstructure, stoichiometry, chemical stability, and transport properties, and the functional properties of a large group of compounds, for which reduction and oxidation processes and mixed ionic-electronic transport, as well as issues related to the phase surfaces play a key role. The proposed interdisciplinary approach was used to develop functional materials that could be used in reversible lithium-ion cells, high-temperature Solid Oxide Fuel Cells, gas separation devices, and ceramic membranes.