Carbon Nanolayer-Wrapped Mesoporous TiO2–B/Anatase for Li+ Storage

Abstract

Optimizing the microstructure, the chemical composition, the surface-wrapped carbon nanolayer, and oxygen vacancies is expected to be an effective strategy for ameliorating electrochemical performance of anode materials. In this work, a series of mesoporous TiO2 with different phase compositions and carbon nanolayers have been rationally designed and constructed. The in situ-synthesized carbon nanolayer could not only lead to the enhanced electric conductivity but also promote the content and stability of TiO2–B in the TiO2–B/anatase mixed phases. Moreover, mesoporous TiO2 composites consisting of different ratios of TiO2–B/anatase with desired interfaces can be obtained by tailoring the carbonization temperature. As a result, the carbon nanolayer-coated mesoporous TiO2 with the dual phase obtained at 600 °C (TiO2–B/anatase@C-6) not only achieves a high specific capacity (473.5 mA h g–1 at 0.1 A g–1) and a superior rate performance (181.9 mA h g–1 at a high current density of 5 A g–1) but also displays a long cycling lifetime by retaining 134% of its initial capacity after 1000 cycles at 1.0 A g–1. The boosted electrochemical properties are owing to synergistic effects of the unique dual phase (TiO2–B/anatase) with an optimized mass ratio, the rich defects in the anatase/TiO2–B interface, the mesoporous structure, and the surface-wrapped highly conductive carbon layer. This work demonstrates an innovative approach to construct mesoporous TiO2 nanocomposites with superior Li+ storage performance.