Fabrication of anatase TiO2/amorphous carbon nanoparticles as anode materials for enhanced lithium ion storage

Abstract

A facile sol-gel method is used to fabricate anatase TiO2/amorphous carbon (a-TiO2/C) and pure a-TiO2 nanoparticles as anode materials in lithium-ion battery. In the a-TiO2/C hybrid, a-TiO2 is generated along with synthesis of amorphous carbon. Thus, a-TiO2 is uniformly embedded into amorphous carbon matrix, which showing a flake structure. The flakes are composed of a number of irregularly sized a-TiO2/C nanoparticles. Moreover, the flakes have porous channels. This designed structure suppresses the growth of a-TiO2 nanoparticles and accelerates the diffusion of lithium ions. Therefore, the hybrid materials exhibit an excellent rate and stability performance compared to pure a-TiO2 in electrochemical testing. The a-TiO2/C anode has discharge capacities of 293 mAh g−1 at 0.05 A g−1 and 172.6 mAh g−1 at 0.5 A g−1. Additionally, the a-TiO2/C anode retains a long cycling performance of 224.4 mAh g−1 at 0.2 A g−1 over 400 cycles with a capacity retention rate of 86.9%. An average capacity fading loss is 0.03275% per cycle, which is lower than 0.1335% of a-TiO2 anode per cycle (initial discharge capacity is 290.5 mAh g−1 and final discharge capacity is 135.4 mAh g−1). The results reveal that compounding of amorphous carbon effectively improves the electrochemical performance of a-TiO2.