Sulfur Incorporation in Hierarchical TiO2 Nanosheet/Carbon Nanotube Hybrids for Improved Lithium Storage Performance

Graphical Energy boost : Simultaneous acceleration of lithium diffusion and electron transport is achieved by homogeneous sulfur incorporation into the hybrids of hierarchical TiO 2 nanosheets and carbon nanotubes (CNTs). Moreover, the numerous interfaces in the 0D-2D-1D architecture provide extra lithium accommodation sites, resulting in dominated capacitive lithium storage processes and boosted high-rate performances of S−TiO 2 /CNTs. To boost the lithium storage performance of TiO 2 , sulfur was homogeneously incorporated into the hybrids of hierarchical TiO 2 nanosheets and carbon nanotubes (CNTs) through a solvothermal-calcination process. The resulting 0D-2D-1D architecture endowed the hybrids with considerable interfaces for lithium accommodation and shortened pathways for lithium diffusion. Moreover, the interplane spacings of TiO 2 and CNTs were expanded and their electronic structures were modified atomically, owing to partial sulfur substitution for oxygen and carbon. Benefitting from the simultaneous acceleration of lithium and electron transport as well as the dominated capacitive charge storage mechanism, lithium-ion batteries based on S−TiO 2 /CNTs delivered an initial discharge capacity of 870.4 mAh g −1 at 0.2 A g −1 , a high-rate capacity of 119.3 mAh g −1 at 5.0 A g −1 and a reversible capacity of 195.5 mAh g −1 at 2.0 A g −1 after 700 cycles, far superior to the counterpart without sulfur doping and comparable to most reported TiO 2 -based nanostructures.