High-rate lithium storage performance of SnSb-Li4Ti5O12 composite anode for Li-ion batteries at low-temperature
The performance of lithium-ion batteries(LIBs)is severely degraded at low temperatures,hindering further development and applications.The commercial graphite anode used in LIBs exhibits slow lithium-ion diffusion and a low lithiation potential,which can lead to lithium plating and consequently poor low-temperature charging capability.In contrast,tin-based anodes show high capacities and moderate lithiation potentials,thus resulting in superior low-temperature performance.This study presents a facile approach to prepare SnSb-Li4Ti5O12 composites through a simple ball-milling method.A fine balance between high capacity and cycling stability was achieved with a 30%LTO composite,which displays excellent high-rate lithium storage capability and cycling stability at room and low temperatures.Specifically,after 300 cycles at 30℃,the composite material delivers a specific capacity of 536 mAh/g,with a capacity retention rate close to 90%.Even at a high rate of 20 A/g(34C),the specific capacity remains at around 280 mAh/g,approximately 50%of that at 0.2 A/g.When cycling 100 times at-30℃ and a current density of 0.2 A/g,a reversible specific capacity of about 413 mAh/g was obtained(74%of room temperature capacity).Moreover,at-30℃ and a rate of 1.0 A/g,a moderate lithiation potential is maintained,and the capacity can reach 61%of the value at room temperature.The results suggest that the phase structure of SnSb remains intact during cycling,which ensures the cycling stability and high-rate capacity.This work demonstrates the possibility of low-temperature applications of SnSb-LTO composite anode materials and provides a basis for the development of fast charging LIBs at low-temperature.
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