Li4Ti5O12 Quantum Dots Decorated Carbon Frameworks from Carbon Dots for Fast Lithium Ions Storage

The spinel Li4Ti5O12 (LTO) shows great security and structural stability as promising anode material for lithium-ion batteries (LIBs), but the application is restricted by its low conductivity and diffusion coefficient. Thus the LTO quantum dots (QDs) anchored on 3D carbon frameworks (CFs) from carbon dots are constructed to overcome these issues, the LTO with quantum size is designed to largely reduce the diffusion distance of Li+ and the 3D CFs are introduced to enhance the electronic conductivity. As expected, the composite attains a high discharge capacity of 191 mAh g-1 at 0.2 C and 115.4 mAh g-1 at a high rate of 40 C, even though the current density comes back to 0.5 C from 40 C, the reversible capacity of 169.1 mAh g-1 could be still restored and the capacity retention is 92.96 %, which is much better than that of bare LTO particles. This work will provide a feasible idea for improving the performances of anode materials for LIBs.