Double core–shell structure H-TiO2/C/Fe3O4@rGO for Li+ battery anodes with long cyclability

Abstract

Anode materials are critical for storage devices based on Li+ batteries (LIBs). This work reports a facile method to produce hydrogenated oxygen vacancy defect TiO2 coated core-shell C/Fe3O4@rGO (H-TiO2/C/Fe3O4@rGO) composite. The volume expansion coefficient of TiO2 in the process of deintercalating lithium ions is about 4%, which can maintain the stable performance of the structure. However, hydrogen engineering can improve its reduced conductivity (i.e., ~1 * 10−12 S/m). The Fe3O4 volume expansion during LIB cycling was inhibited by the hydrogenated oxygen vacancy defect TiO2 (H-TiO2). The H-TiO2/C/Fe3O4@rGO composite showed outstanding electrochemical properties (867 mAh g−1 after 200 cycles at 0.3 A g−1), and long cycle performance (505 mAh g−1 after 700 cycles at 1.0 A g−1).