Optimizing charge dynamics in Ti₂Nb₁₀O₂₉ anode via strategic orbital hybridization and delocalized electronic...

Ti₂Nb₁₀O₂₉ (TNO) anodes demonstrate significant potential for fast-charging lithium-ion batteries (LIBs) owing to their inherent safety, high capacity, and robust durability. However, their practical implementation is constrained by sluggish Li⁺ diffusion kinetics and limited electronic conductivity. In this study, we systematically explore the impact of strategically incorporating trivalent heteroatoms (Ti₂Nb_9.9M_0.1O₂₉, denoted as M-TNO, where M = Al, Fe, Y, La, and Gd) on the orbital hybridization and delocalized electronic structure of TNO. Specifically, elements with unsaturated outer electrons (e.g., Fe and Gd) introduce dopant energy levels within the bandgap, thereby enhancing the electrochemical response. Meanwhile, elements with larger electronic configurations (e.g., La and Gd) promote hybridization between their 5d orbitals and the Ti 3d and O 2p orbitals, improving reaction kinetics. Among the modified samples, Gd-TNO exhibits the most pronounced enhancement in Li⁺ diffusion kinetics, attributed to Gd-induced interlayer expansion and shortened diffusion pathways. The optimized Gd_0.1-TNO delivers a high capacity of 295.0 mAh g^-1 at 0.5 C, an exceptional rate capacity of 190.9 mAh g^-1 at 10 C, and remarkable cycling stability with a minimal capacity loss of 0.038 % per cycle over 1000 cycles at 10 C. This work provides critical insights into the role of trivalent heteroatoms in enhancing the performance of TNO anodes, offering a novel strategy for the design of high-performance LIB materials.