Li4Ti5O12 quantum dot decorated carbon frameworks from carbon dots for fast lithium ion storage

Abstract

Spinel Li₄Ti₅O₁₂ (LTO) shows great security and structural stability as a promising anode material for lithium-ion batteries (LIBs), but its application is restricted by its low conductivity and diffusion coefficient. Thus, LTO quantum dots (QDs) anchored on 3D carbon frameworks (CFs) from carbon dots are constructed to overcome these issues; LTO with a quantum size is designed to largely reduce the diffusion distance of Li⁺ and 3D CFs are introduced to enhance the electronic conductivity. As expected, the composite attains a high discharge capacity of 191 mA h g⁻¹ at 0.2C and 115.4 mA h g⁻¹ at a high rate of 40C; even when the current density is reduced back to 0.5C from 40C, the reversible capacity of 169.1 mA h g⁻¹ can still be 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 performance of anode materials for LIBs.