P-doping induced oxygen vacancies in ultrathin TiO2 Nanosheets@CNT heterostructure for high-rate and long-cycle sodium-ion storage

A hierarchical P-TiO 2 @CNTs heterostructure is fabricated via synergistic defect and architecture engineering. • P-doping in situ triggers abundant oxygen vacancies and optimizes electronic structure for fast Na + transport. • 3D CNT network guides vertical growth of ultrathin TiO 2 nanosheets and suppresses agglomeration. • The P-TiO 2 @CNTs anode exhibits ultra-long cycling stability with 0.019% low-capacity decay rate per cycle after 3000 cycles at 2.0 A g −1 . A hierarchical P-TiO 2 @CNTs heterostructure is rationally designed via synergistic defect and architecture engineering for high-performance sodium-ion batteries. The CNT backbone acts as both a conductive network and a structural template to direct the vertical growth of ultrathin TiO 2 nanosheets, effectively suppressing agglomeration and shortening Na + diffusion paths. P-doping not only induces abundant surface oxygen vacancies to optimize the electronic band structure, and enrich active sites but also modulates lattice interspacing for accelerated Na + diffusion. Benefiting from the synergy of P-doping-triggered vacancies and 3D conductive CNT networks, the P-TiO 2 @CNTs anode delivers exceptional rate capability and ultra-long cycling stability (0.019% low-capacity decay rate per cycle after 3000 cycles at 2.0 A g −1 ). This work provides a universal strategy for integrating defect engineering and hierarchical architecture design to develop advanced TiO 2 -based anodes for high-power and long-life sodium-ion storage. Download: Download high-res image (351KB) Download: Download full-size image