Presentation Title: The Role Mechanism and Application of Niobium in Ni-rich Polycrystalline and Single-crystal Ternary Cathode Materials

Abstract: 

     Niobium modification of Ni-rich polycrystalline and single-crystal ternary cathodes to enhance structural stability has become a consensus in both academia and industry. However, how to effectively achieve modification for performance maximization in practical applications still faces numerous challenges. This report first reveals the abnormal failure phenomenon of cycling stability in niobium-doped polycrystalline Ni-rich cathodes via the solid-state method when the synthesis temperature approaches a critical point, and delves into the underlying mechanism behind this failure. To address this issue, we propose introducing niobium during the precursor preparation stage to construct a unique gradient structure with a niobium-enriched shell and niobium-deficient core, successfully circumventing the critical temperature failure risk. After high-temperature lithiation, the material forms a dense nanoscale primary particle network at the surface and relatively larger submicron primary particles in the interior, achieving spatial functional decoupling. For single-crystal Ni-rich cathodes, we further propose a descriptor-driven, machine-learning-assisted, entropy-tuned synergistic doping strategy that transcends conventional empirical trial-and-error screening. By integrating random forest-based nonlinear ranking, feature importance analysis, and agglomerative hierarchical clustering of multidimensional physicochemical descriptors, we establish a quantitative framework to elucidate dopant compatibility rules and identify functionally complementary cross-cluster combinations. This prescreening framework provides a transferable descriptor-driven paradigm for the rational design of high-power single-crystal Ni-rich cathodes, offering promising prospects for accelerating the development of high-performance cathode materials. 

Biography: 

      Xuejie Huang, Research Professor at the Institute of Physics (CAS) and Songshan Lake Materials Laboratory. He serves as an expert in the Overall Group of the National Key R&D Program for New Energy Vehicles, Chief Scientist of the High-Energy-Density Battery Project under the National Key Special Program for Transformative Technologies. He is also Editor-in-Chief of Energy Storage Science and Technology and Vice Chairman of the China Battery Industry Association. Since 1996, he has led the Solid-State Ionics and Energy Materials Group at the Institute of Physics, CAS, overseeing research, development, and industrialization of liquid and semi-solid lithium-ion batteries, all-solid-state lithium batteries, and their key materials. He has published over 400 journal papers and been granted more than 130 invention patents.