Constructing ion/electron dual highways in Pr3+-doped TiNb2O7 via a tri-doped carbon framework

Titanium niobium oxide (TiNb₂O₇, TNO) holds great promise as an anode material for lithium-ion batteries but is hindered by insufficient intrinsic capacity and sluggish Li + diffusion kinetics in practical applications. Herein, we report a high-performance TNO-based nanocomposite fabricated via a synergistic strategy integrating Pr 3+ doping and encapsulation in a N/O/S tri-doped honeycomb-like porous carbon framework. Pr 3+ ions with a large ionic radius (1.126 Å) are incorporated into TNO nanospheres (100–200 nm), inducing oxygen vacancies and lattice expansion to broaden ion diffusion pathways and accelerate Li + transport. Simultaneously, the tri-doped honeycomb carbon serves as a three-dimensional conductive network, efficiently buffers volume variations during cycling, and constructs robust Ti–O–C heterointerfaces, which collectively reduce Li + diffusion barriers. Benefiting from these synergistic effects, the optimized composite exhibits exceptional electrochemical performance: the half-cell delivers a specific capacity of 205.61 mAh g −1 at 20C and retains 174.79 mAh g −1 after 2000 cycles (retention rate > 85%), whereas the full-cell assembled with a LiFePO₄ cathode maintains 115.39 mAh g −1 after 2000 cycles at 10C. This work highlights that the synergistic integration of Pr 3+ doping and carbon heterointerface engineering significantly enhances the lithium storage kinetics and structural stability of TNO-based anodes, offering a promising strategy for the development of advanced high-performance lithium-ion battery electrodes.