Morphology-tuned carbon-doped black TiO2 hollow nanomaterials for fast and durable lithium-ion battery anodes

초록

Nanostructured titanium dioxide (TiO2) has attracted considerable interest as a novel anode material for lithium-ion batteries (LIBs). Further innovations in design will require careful morphological engineering of TiO2 to optimize structure-property relationships for enhanced electrochemical performance while ensuring practicality. In this study, black carbonized double-shell hollow TiO2 (c-DS/HT) nanoparticles coated with conductive carbon layers are synthesized as high-performance anodes. The c-DS/HT structures are engineered to enhance specific capacity, rate performance, and long-term cycling stability. This is achieved through a synergistic design strategy incorporating oxygen vacancy generation, double-shell hollow architecture, and conductive carbon surface modification. These modifications significantly enhance both lithium-ion diffusion and electron transport. The double-shell porous morphology facilitates efficient electrolyte penetration and shortens the ion diffusion pathways, while oxygen-deficient sites enhance the charge transport kinetics. As a result, c-DS/HT electrodes demonstrate a high specific capacity of 178.8 mAh g-1 at 1 C and retain 95.6 % capacity after 300 cycles. Electrochemical analysis results confirm reduced charge-transfer resistance and rapid ion diffusion, with an apparent diffusion coefficient value of 1.73 x 10-10 cm2 s-1. These findings highlight the potential of c-DS/HT as a next-generation black TiO2-based anode material, overcoming the intrinsic kinetic limitations of conventional TiO2 and offering a promising platform for high-rate, durable LIBs.

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