In situ self-nucleophilic synthesis of nano-Li 4 Ti 5 O 12 /reduced graphite oxide composite with mesopore-oriented porous structure for high-rate lithium ion batteries

It is the core to improve the electron/ion transfer features of Li 4 Ti 5 O 12 for achieving high-rate anode in lithium ion batteries. By directly using graphite oxide powder, nano-Li 4 Ti 5 O 12 /reduced graphite oxide composite with mesopore-oriented porosity is prepared through one-pot facile ball-milling method in this work. Synthesis mechanism underlying the self-nucleophilic effect of oxygen-containing functional groups in graphite oxide is substantiated. Reactants can intercalate into graphite oxide bulk and in-situ generate nanoparticles. Subsequently, graphite oxide with nanoparticles generated inside can obtain a mesopore-oriented porous structure under ball-milling. Furthermore, the synergistic effects of Li 4 Ti 5 O 12 nanoparticles and mesopore-oriented porosity strengthen composites with rapid Li + diffusion and electron conductive frameworks. The obtained optimal LTO/GO-1.75 composite displays excellent high-rate capability (136 mA·h/g at 7000 mA/g) and good cycling stability (a capacity retention of 72% after 1000 cycles at 7000 mA/g). Additionally, the reactants concentration in this demonstrated strategy is as high as 30 wt%–40 wt%, which is over 6 times that of traditional methods with GO suspensions. It means that the strategy can significantly increase the yield, showing big potential for large-scale production.