Li_4Ti_5O_(12)/Sn composite anodes for lithium-ion batteries: Synthesis and electrochemical performance

摘要

Li_4Ti_5O_(12)/tin phase composites are successfully prepared by cellulose-assisted combustion synthesis of Li_4Ti_5O_(12) matrix and precipitation of the tin phase. The effect of firing temperature on the particulate morphologies, particle size, specific surface area and electrochemical performance of Li_4Ti_5O_(12)/tin oxide composites is systematically investigated by SEM, XRD, TG, BET and charge-discharge characterizations. The grain growth of tin phase is suppressed by forming composite with Li_4Ti_5O_(12) at a calcination of 500 ℃, due to the steric effect of Li_4Ti_5O_(12) and chemical interaction between Li_4Ti_5O_(12) and tin oxide. The experimental results indicate that Li_4Ti_5O_(12)/tin phase composite fired at 500℃ has the best electrochemical performance. A capacity of 224 mAh g~(-1) is maintained after 50 cycles at 100 mA g~(-1) current density, which is still higher than 195 mAh g~(-1) for the pure Li_4Ti_5O_(12) after the same charge/discharge cycles. It suggests Li_4Ti_5O_(12)/tin phase composite may be a potential anode of lithium-ion batteries through optimizing the synthesis process.