A new composite material Li4Ti5O12–SnO2 for lithium-ion batteries

A new Li4Ti5O12–SnO2 composite anode material for lithium-ion batteries has been prepared by loading SnO2 on Li4Ti5O12 to obtain composite material with improved electrochemical performance relative to Li4Ti5O12 and SnO2. The composite material was characterized by X-ray diffraction and scanning electron microscopy. The results indicated that SnO2 particles have encapsulated on the surface of the Li4Ti5O12 uniformly and tightly. Electrochemical results indicated that the Li4Ti5O12–SnO2 composite material increases the reversible capacity of Li4Ti5O12 and has good cycling reliability. At a current rate of 0.5 mA/cm2, the material delivered a discharge capacity of 236 mAh/g after 16 cycles. It suggests the existence of synergistic interaction between Li4Ti5O12 and SnO2 and that the capacity of the composite is not a simple weighted sum of the capacities of the individual components. In the composite material, SnO2 can act as a bridge between the spinel particles to reduce the interparticle resistance and as a good material for the Li intercalation/deintercalation. Thus, electrochemical performance of the Li4Ti5O12 spinel can be improved by the surface modification with SnO2, and the stability of Li4Ti5O12 also serves to buffer the internal stress caused by the volume changes in lithium insertion and extraction reactions.