In situ deposition method preparation of Li_4Ti_5O_(12)-SnO_2 composite materials for lithium ion batteries

摘要

A Li_4Ti_5O_(12)-SnO_2 composite anode material for lithium-ion batteries has been prepared by loading various amounts of nano-SnO2 on Li4Ti5Oi2 to obtain composite materials with improved electrochemical performance relative to Li_4Ti_5O_(12) and SnO_2. The composite materials were characterized by XRD, IR and SEM. The results indicated that SnO_2 particles have encapsulated on the surface of the Li_4Ti_5O_(12) uniformly and tightly. The influence of SnO2 proportion on the electrochemical properties of Li_4Ti_5O_(12)-SnO_2 composite material was investigated and discussed. The results showed that Li_4Ti_5O_(12)-SnO_2 (5 percent) has the best cycling behavior among all the samples. At a current rate of 0.5 mA cm~(-2), the material delivered a discharge capacity of 189 mAh g~(-1) after 42 cycles. Electrochemical results indicated that the Li_4Ti_5O_(12)-SnO_2 composites increased the reversible capacity of Li_4Ti_5O_(12) and cycling reliability of the SnO_2 anode material. It suggests the existence of synergistic interaction between Li_4Ti_5O_(12) and SnO_2 and that the capacity of the composite is not a simple weighted sum of the capacities of the individual components.