Cu^(2+)掺杂高密度LiFePO_4/C正极材料的合成及性能  

Synthesis and performance of high tap density LiFePO_4 cathode materials doped with copper ions

作　　者：常照荣[1] 吕豪杰[1] 汤宏伟[1] 付小宁[2] 李华吉[1] 

机构地区：[1]河南师范大学化学与环境科学学院,河南新乡453007 [2]新乡学院化学与环境工程学院,河南新乡453007

出　　处：《功能材料》2009年第10期1682-1684,共3页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(20671031)

摘　　要：以高密度FePO4作为前躯体,Cu(Ac)2为掺杂源,通过高温固相法合成了高振实密度的锂离子电池正极材料LiFe1-xCuxPO4/C(x=0、0.01、0.015、0.02、0.025)。采用X粉末衍射(XRD)、电子扫描显微镜(SEM)、循环伏安法(C-V)和恒电流充放电对合成的材料掺杂进行了结构、形貌和电性能表征和分析研究。结果表明,所合成的掺杂复合材料LiFe1-xCuxPO4/C为典型的橄榄石型结构,结晶度高,具有较高的振实密度。掺杂Cu2+离子在很大程度上可以提高LiFePO4的电化学性能,当Cu含量为2.0%(质量分数)时,LiFe0.98Cu0.02PO4/C的振实密度可以达到1.98 g/cm3,比容量为最大值,0.1C倍率放电可达150.0mAh/g,体积比容量为297.0mAh/cm3;2C倍率放电比容量仍可以达到127.3mAh/g以上,体积比容量为252.1mAh/cm3。Stoichiometric Cu-doped lithium iron phosphate LiFe1-xCuxPO4/C（x=0、0.01、0.015、0.02、0.025） cathode material was synthesized by a solidstate reaction in an inert atmosphere which used Cu（Ac）2 as dopant. The LiFePO4 samples were characterized by X-ray difraction,scanning electron microscope and electrochemical performance testing. The results indicate that the cathode material is well crystallized,homogeneous olivine-type phase. The ion dopants do not affect the structure of the material but considerably improve its electrochemical performance. The content of Cu is an important factor to influence the performance of LiFePO4. With the Cu content of 2.0wt%, the tap density of LiFePO4/C reaches 1.98g/cm^3. Charge-discharge test showed that the cathode materials possess excellent charge/discharge capacities, about 150mAh/g and 297.0mAh/V at 0. 1C rate and more than 127.3mAh/g and 252. 1mAh/cm^3 at 2C rate.

关 键 词：正极材料 锂离子电池 LiFe1-xCuxPO4 离子掺杂 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]