Interface-enhanced TiO2@C@CNTs supraspheres enabled by emulsion-assisted co-assembly for high-efficiency lithium-ion storage

Fabrication of nanostructured composites from diverse functional building blocks is of great significance for advanced electrochemical energy storage. However, conventional nanocomposites normally exhibit inferior collective properties owing to insufficient interfacial coupling and weak intercomponent interactions. In this work, carbon nanotubes (CNTs) and needle-shaped TiO 2 crystals were surface-modified with long-chain hydrocarbon ligands, followed by co-assembly into uniform spherical nanocomposites via an emulsion-assisted strategy. After subsequent carbonization, the hydrocarbon chains of ligands entangled and in-situ transformed into ultrathin carbon layers, which robustly bridged TiO 2 and CNTs to generate enhanced interfacial coupling within the obtained supraspheres. The effects of TiO 2 /CNTs ratios on the co-assembly behavior of supraspheres and their electrochemical performance as lithium-ion battery anode materials were systematically investigated. Leveraging the reinforced interfacial effect and conductive CNTs network, the optimized TiO 2 @C@CNTs supraspheres delivered a reversible specific capacity of 261 mAh g −1 at 0.5 A g −1 , and retain 198, 156, 115, and 78 mAh g −1 at high current densities of 2, 5, 10, and 20 A g −1 , respectively, demonstrating high lithium storage capacity, superior rate capability, and excellent long-term cycling stability. The developed emulsion-assisted co-assembly approach provides a universal route to construct high-performance nanocomposites with enhanced collective electrochemical properties for advanced energy storage devices.