不同气氛下裂解含苯环聚硅氧烷制备锂离子电池Si-O-C复合负极材料的电池性能研究

Electrochemical property of Si-O-C composite anode materials prepared by pyrolyzing polysiloxane containing phenyl under different atmospheres

在惰性气氛Ar和还原性气氛H2中通过高温裂解含苯环的聚硅氧烷分别制备了硅氧碳化物Si-O-C复合负极材料,并且采用了元素分析element analysis、广角粉末X射线衍射XRD、傅里叶激光拉曼光谱Raman等手段表征了二者组成和结构的差别.实验发现,在H2气氛中裂解制备的Si-O-C复合负极含有较高的可逆、较低的不可逆容量,而且可逆容量随温度的增加而增长.其中H2气氛中1000℃情况下制备的Si-O-C复合负极的可逆容量622mAh/g,首次库仑效率59%.Si-O-C复合负极的不可逆容量与氧的含量相关,可逆容量可能与碳含量及碳结构,以及SiOC中硅的结构相关.在H2气氛中制备的Si-O-C负极材料是一种潜在的锂离子电池的负极材料.

Silicon Oxycarbide （Si-O-C） composite anode materials are prepared by pyrolysis of polysiloxane containing phenyl under argon and hydrogen atmospheres,separately.They are characterized by element analysis,wide-angle powder X-ray diffraction,Raman spectroscopy for comparison with each other.It is found that the silicon oxycarbide composite anode pyrolyzed under a hydrogen atmosphere demonstrates lower irreversible capacity and larger reversible capacity which increases with temperature rising.The one pyrolyzed at 1000℃ shows a reversible capacity of 622 mAh/g,and first coulombic efficiency of 59%.The magnitude of the irreversible capacity is correlated with the content of oxygen,and the reversible capacity is related to the content and structure of free carbon,and also the structure of Si-O-C.It is believed that Si-O-C composite materials pyrolyzed under a hydrogen atmosphere could be promising anode materials for lithium ion batteries.