摘 要:本论文采用无焰燃烧合成法，制备5V锂离子电池正极材料LiNi0.5Mn1.5O4，在400℃时焙烧时间为30min，1h，3h，6h，12h，取出空冷制成的活性物质，研究了相同温度不同焙烧时间对电性能的影响。
循环性能研究发现，当焙烧时间为30min时，其初始放电容量为80mAh/g，首次充放电效率为96%，经过30次循环后容量为79mAh/g，容量衰减率为1.25%；电流密度从30mA/g变大为75mA/g，放电容量下降为70mAh/g，在75mA/g下循环30次后容量为65 mAh/g，循环性能较好。当焙烧时间为1h时，初始放电容量为131mAh/g，首次充放电效率为98.6%，经过30次循环后容量为126mAh/g，容量衰减为3.8%；电流密度从30mA/g变大为75mA/g，放电容量下降为89mAh/g，在75mA/g下循环30次后容量为85mAh/g，循环性能很好。当焙烧时间为3h时，其初始放电容量为80mAh/g，首次充放电效率为95.7%，30次后放电容量为76mAh/g，容量衰减率为5%；电流密度从30mA/g变大为75mA/g，放电容量下降54mAh/g，在75mA/g下循环30次后容量53mA/g，循环性能好。当焙烧时间为6h时，初始放电容量为110mA/g，首次充放电效率96.2%，经过30次循环后容量105mA/g容量衰减率为4.5%；电流密度从30mA/g变大为75mA/g，放电容量下降为100mA/g，在75mA/g下循环30次后容量为95mA/g，循环性能好。当焙烧时间为12h时，其初始放电容量为115mA/g，首次充放电效率为95.8%，经过30次循环后放电容量为110mAh/g，容量衰减率为4.3%；电流密度从30mA/g变大为75mA/g，放电容量下降105mAh/g，在75mA/g下循环30次后容量105mAh/g，循环性能好。
放电曲线表明，焙烧时间对放电比容量影响较大，在一定温度范围内随焙烧时间的升高而增大，放电比容量增加，合成材料的性能增强，但若焙烧时间过长反而会使放电比容量降低，材料性能减弱。其中,电性能最好的样品为400oC时焙烧时间为3h所得样品,其初始容量为80mAh/g,30次循环后,容量衰减率为5%，电池的充放电平台高且稳定，电池的充放电循环稳定性较好。
关键词： 无焰燃烧法，锂离子电池， LiNi0.5Mn1.5O4， 5V正极材料
ABSTRACT:This paper adopted themethod of flameless combustion synthesis, investigating the influence of same temperature and different sintering conditions on electrical properties by preparing 5V lithium-ion battery cathode material LiNi0.5Mn1.5O4 under 30min, 1h, 3h, 6h, 12h at 400 ℃ and obtaining the living contents produced by cold air.
Cycle performance study found that, when roasting time was 30min, the initial discharge capacity was 80mAh / g, the first charge-discharge efficiency of 96%, after 30 cycles, capacity was 79mAh / g, the rate of capacity decay was 1.25%; current density changed from 30mA / g to75mA / g, the discharge capacity decreased to 70mAh / g, at 75mA / g, after 30 cycles at a capacity of 65mAh / g, the cycle performance was better. When roasting time was 1h, the initial discharge capacity was 131mAh / g, the first charge-discharge efficiency was 98.6% after 30 cycles, the capacity was 126mAh / g, the capacity declined to 3.8%; current density changed from 30mA / g to 75mA / g, the discharge capacity decreased to 89mAh / g, in 75mA / g after 30 cycles under the capacity of 85mAh / g, the cycle performance was good. When the roasting time was 3h, the initial discharge capacity was 80mAh / g, for the first time, the first charge-discharge efficiency was 95.7%, after 30 cycles, the discharge capacity was 76mAh / g, the rate of capacity decay was 5%; current density changed from 30mA / g to 75mA / g, the discharge capacity decreased to 54mAh / g, at 75mA / g, after 30 cycles under the capacity of 53mA / g, cycle performance is very good. When the roasting time was 6h, the initial discharge capacity was 110mA / g, the first charge-discharge efficiency was 96.2%, after 30 cycles, the rate of decay of the capacity was105mA / g 4.5%; current density changed from 30mA / g to 75mA / g, the discharge capacity dropped to 100mA / g, at 75mA / g after 30 cycles under the capacity of 95mA / g, cycle performance was good. When baking time was 12h, the initial discharge capacity was 115mA / g, the first charge-discharge efficiency was 95.8%, after 30 cycles, the discharge capacity was 110mAh / g, the decay rate of capacity was 4.3%; current density changed from 30mA / g to 75mA / g, the discharge capacity decreased to 105mAh / g, at 75mA / g after 30 cycles under the capacity of 105mAh / g, cycle performance was good.
Discharge curve showed that: the baking time had a greater impact on the discharge capacity. At a certain temperature range, the discharge capacity increased with the increase of sintering time, when discharge capacity increased, the performance of synthetic materials increased. But if the baking time was too long so the discharge capacity would decrease, the performance of synthetic materials increased. Among them, the best sample of the electrical properties was the sample that its roasting time was 3h under 400 ℃ , with an initial capacity of 80mAh / g, after30 cycles, the rate of capacity decay was 5%, the battery charge and discharge platform was high and stable , the stability of battery charge-discharge cycle was better.
Keywords: the method of flameless combustion， lithium-ion battery， LiNi0.5Mn1.5O4，5V cathode materia
