摘要
采用共沉淀法合成了纯相橄榄石型磷酸铁锂(LiFePO4)和磷酸铁锂掺碳(LiFePO4/C)复合正极材料。利用X射线衍射(XRD)、原子吸收(AAS)、扫描电镜(SEM)、红外吸收(FT-IR)、振实密度测定等方法对其进行表征,并组装成电池研究其电化学性能。结果表明:LiFePO4和LiFePO4/C具有单一的橄榄石型晶体结构,前者的振实密度可达1.58 g/cm2,LiFePO4/C振实密度有所降低,但充放电平台非常平稳。与纯相LiFePO4相比,LiFePO4/C具有更高的放电比容量和循环性能,室温下以0.05 C和0.1 C倍率电流充放电,首次放电比容量达到158.1,150.0 mA.h/g。充放电循环20次后放电比容量仍保持在154.2,137.2 mA.h/g。
Pure phase olivine- type LiFePO4 and LiFePO4/C composite cathode materials were successfully synthesized by co - precipitation method. The properties of LiFePO4 and LiFePO4/C were systemically characterized by the methods of XRD, AAS, SEM, FT - IR,tapped density determination etc.. The electrochemical properties were tested by analogous cells. The results showed that LiFePO4 and LiFePO4/C were both simple pure phase olivine - type crystal structure and the tapped density of the former can get to 1.58 g/cm^3. After carbon coating,the tapped density decreased a little but it had a good charge - discharge voltage plateau. Compared with pure phase LiFePO4 ,LiFePO4/C had better discharge specific capacity and excellent cycle performance,whose initial discharge specific capacity was 158.1 mA · h/g at 0.05 C under room temperature,even at 0. 1 C,LiFePO4/C also had high discharge specific capacity, which was 150.0 mA · h/g. After 20 times cycling, the discharge specific capacity were 154.2 mA · h/g, 137.2 mA · h/g respectively.
出处
《无机盐工业》
CAS
北大核心
2008年第1期22-25,共4页
Inorganic Chemicals Industry
