为研究针状焦制备条件对锂离子电池性能的影响,对煤焦油沥青在热缩聚反应过程中形成半焦进行研究,并通过偏光显微镜和X射线衍射光谱(XRD)对聚合产物形貌结构进行表征,着重研究了煤沥青聚合过程中温度、时间和压力对聚合产物形貌结构的影响。试验结果表明:温度对反应的进行影响最明显,当温度低于430℃,反应进行较长时间仍无法使产物焦化。当温度440℃时可通过控制时间和体系压力调整聚合产物的形貌结构,聚合得到的焦化产物的结构为细粒或细粒与粗粒共存的镶嵌结构。对比不同压力下聚合产物经炭化和石墨化后的电化学数据可知,压力为2MPa条件下1000℃炭化的中间相焦具有最高的充放电比容量:放电比容量为219mAh/g,充电比容量为268mAh/g;经2800℃石墨化处理后,循环50次后比容量为331mAh/g,保持率为98%。

In order to study the influence of the preparation conditions of needle coke on the performance of lithium-ion batteries, the for⁃mation of semi-coke were studied during the thermal polycondensation reaction of coal tar pitch, and the morphological structure of thepolymerized products was characterized by polarized light microscopy and X-ray diffraction spectroscopy (XRD), focusing on the effectsof temperature, time and pressure on the polymerized products during the polymerization of coal pitch. The effect of temperature, time andpressure on the structure of the polymerized products was investigated. The experimental results shows that the temperature has the mostobvious influence on the reaction, and when the temperature is lower than 430 ℃ , the reaction can not further coke the product for a lon⁃ger time. When the temperature is 440 ℃ , the structure of the polymerization product can be controlled by time and pressure, and thestructure of the polymerization product is fine grains or mosaic structure of fine grains and coexistence of coarse grains. Comparing the elec⁃trochemical data of the polymerized product after charring and graphitization under different pressure, it can be seen that the condition ofpressure 2 MPa has the highest charge/ discharge specific capacity, the charge specific capacity is 219 mAh/ g and the discharge specif⁃ic capacity is 268 mAh/ g. After graphitization of 2 800 ℃ and 50 cycles, the specific capacity is 331 mAh/ g and the retention rateis 98%.

0 引言

1 试验

   1.1 原料

   1.2 试验方法

   1.3 分析测试

2 结果与讨论

   2.1 聚合产物收率及灰分分析

   2.2 聚合产物的偏光分析

   2.3 聚合产物XRD图谱分析

   2.4 聚合产物的炭化和石墨化及电化学性能

   2.5 炭化产物电化学性能

   2.6 石墨化产物电化学性能

   2.6 石墨化产物电化学性能

3 结论