Abstract: Pure phase olivine-type LiFePO4 and composite cathode material LiFePO4/C were synthesized by the liquid-state co-precipitation method. The properties of LiFePO4 and LiFePO4/C were systemically studied via the methods of AAS，XRD，SEM，tapped density，etc. The electrochemical properties were tested by using analogous assembled cells. The results showed that LiFePO4 and LiFePO4/C were both simple pure phase olivine-type and the tapped density of the former could reach 1.67 g/cm3. After carbon coating，the tapped density decreased a little but had a good charge-discharge voltage plateau. Compared with pure phase LiFePO4，LiFePO4/C had better discharge capacities and excellent cycle performance，and its first discharge capacity was 158.1 mA·h/g at 0.2 mA/cm2 and even at 0.4 mA/cm2at room temperature，LiFePO4/C also had high discharge capacity of 150.0 mA·h/g. After 20 times cycling，the specific capacities were 154.2 mA·h/g，137.2 mA·h/g respectively.

摘要： 采用液相共沉淀法合成了纯相橄榄石型LiFePO4和LiFePO4/C复合正极材料。利用原子吸收(AAS)、X射线衍射(XRD)、扫描电镜(SEM)、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都具有单一的橄榄石型晶体结构，且前者的振实密度可达1.67 g/cm2，掺碳后制成的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0.2 mA/cm2和0.4 mA/cm2电流密度充放电，首次放电比容量分别达到158.1 mA·h/g、150.0 mA·h/g。充放电循环20次后放电比容量仍分别保持在154.2 mA·h/g，137.2 mA·h/g。