Shape-controlled synthesis of Ti4O7 nanostructures under solvothermal-assisted heat treatment and its application in lithium-sulfur batteries

Abstract

Here we report a facile approach to synthesize a series of pure Ti4O7 nanostructures via solvothermal process and subsequent thermal treatment. The one-dimensional of Ti4O7 nanorods (1D Ti4O7 NRs) and three-dimensional of Ti4O7 nanoparticles (3D Ti4O7 NPs) were successfully achieved and investigated well by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HR-TEM), and Brunauer-Emmett-Teller analysis (BET). The as-prepared Ti4O7 nanostructures were used as additive to prepare Ti4O7/sulfur composite cathodes. The initial discharge capacity of the sulfur cathode with the added Ti4O7 NRs was 1050 mAh g−1, and remaining capacity was 580 mAh g−1 after 300 cycles at 1C. Even at a high current density of 2C, it also kept at a high discharge capacity of 590 mAh g−1. Compared with Ti4O7 NPs/sulfur electrode, the electrodes containing Ti4O7 NRs show the excellent cycling and rate performance, confirming that the morphology of Ti4O7 could effectively influence its electrochemical performance for lithium sulfur batteries. The good electrochemical properties of Ti4O7 NRs can be attributed to the higher catalytic activity in the lithium-sulfur redox reaction, the lower charge-transfer resistance and larger lithium ion diffusion coefficient.