Facile synthesis of uniform N-doped carbon-coated TiO2 hollow spheres with enhanced lithium storage performance

Abstract

Great efforts, such as nano-structuring and carbon coating, have been devoted to addressing the poor rate performance of TiO₂ anodes in lithium ion batteries, which is mainly caused by sluggish Li ion diffusion and poor electrical conductivity of the bulk material. However, the complicated fabrication processes make most of these strategies much low practical significance. Herein, a scalable and facile strategy based on sacrificial template-accelerated hydrolysis and polydopamine coating is proposed to manufacture uniform N-doped carbon-coated TiO₂ hollow spheres. The nanostructured hollow structure can shorten the path of Li⁺ insertion/extraction in the electrode material. More importantly, the uniform carbon layer can improve the electronic conductivity of TiO₂ during long-term cycling. Thus, a reversible capacity can be obtained of as high as 390.2 mA h g⁻¹ at a current density of 0.1 A g⁻¹. Furthermore, a high capacity of 166.3 mA h g⁻¹ after 2000 cycles at 5.0 A g⁻¹ shows that the carbon-coated TiO₂ hollow spheres deliver good capacity retention and cycling performance.