交联剂的引入对碳负极材料性能的影响

Effects of the Addition of a Crosslinker on Properties of Carbon Anode Materials 

研究了引入的交联剂二乙烯基苯对作为锂离子二次电池负极材料的聚合物裂解碳性能的影响.结果表明交联剂引入到聚丙烯腈中后,在热处理过程中有利于该聚合物的碳化,导致层间距d002减少及石墨微晶尺寸增加;交联剂的固定作用使碳材料的有序性得到了提高;同时微孔数目也得到了增加.这些因素的影响导致了聚合物裂解碳的可逆储锂容量随交联剂的量的增加而提高.对于别的加聚物如聚4乙烯吡啶而言,同样也使所得到的聚合物裂解碳的可逆储锂容量得到了提高.最大可逆容量可达600mAh·g-1.

A novel kind of polymeric carbons has been prepared by heat treating addition polymers with a crosslinker divinyl benzene (DVB) at 600 ℃. Effects of DVB on the properties of anode materials based on polyacrylonitrile (PAN) for lithium ion secondary battery were studied through the measurements of X ray powder diffraction, elemental analysis, scanning electron microscopy, specific surface area and reversible lithium capacity. The crosslinker DVB favors carbonization process and the contents of H and N in the prepared polymeric carbons are decreased. This kind of carbons is amorphous, however, after the addition of crosslinker DVB, the interlayer distance d 002 decreases and the size of graphite crystallites( Lc ) increases. The action of fixing of the incorporated DVB leads to more ordered stacking of graphene molecules during theheat treatment. In addition, the number of micropores increases. These favorable factors result in the reversible lithium capacity of carbon anode based on PAN enhancing with the amount of crosslinker DVB added. This enhancement also applies to polymeric carbon based on other additional polymers. Results of polymeric carbons based on poly(4 vinyl pyridine)shows the same tendency. The highest reversible capacity can be up to 600 mAh·g -1 .