基于Li3PO4水热法制备LiFePO4及其改性  

LiFePO_4 synthesized by hydrothermal method from Li_3PO_4 and its modification

作　　者：张卫新[1] 赵飞[1] 王强[1] 杨则恒[1] 

机构地区：[1]合肥工业大学化工学院,可控化学与材料化工安徽省重点实验室,安徽合肥230009

出　　处：《化工学报》2010年第10期2719-2725,共7页CIESC Journal

基　　金：国家自然科学基金项目(20871038, 20876031,20976033);安徽省教育厅创新团队计划项目(TD200702)~~

摘　　要：以自制Li3PO4为前驱体,在水热条件下与FeSO4.7H2O反应制备得到纯相LiFePO4,并通过碳包覆和Cu2+掺杂对其进行了有效改性,获得了适合高电流密度放电的LiFePO4正极材料。采用X射线衍射(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对产物进行了物相和形貌表征。实验研究了水热反应温度对产物的形貌及其电化学性能的影响,同时探讨了掺杂Cu2+对材料常温和低温电化学性能的影响。结果表明:在200℃、24h水热条件下制得的产物,经碳包覆后的复合材料LiFePO4/C(LFP200/C),以1C(150mA.g-1)电流放电,放电比容量达140.7mAh.g-1;对材料进行Cu2+掺杂得到的Cu-LFP200/C材料的放电比容量及倍率性能得到进一步提高,常温下1C倍率的放电比容量为150.3mAh.g-1,10C倍率的放电比容量为108.7mAh.g-1,在-30℃条件下的放电比容量依然达到97mAh.g-1。LiFePO4,as cathode material of lithium ion batteries,which was suitable for discharge at high current density,was prepared by carbon-coating and Cu2＋-doping modification of pure LiFePO4 synthesized from self-prepared Li3PO4 and FeSO4·7H2O at hydrothermal condition.The effects of hydrothermal temperature on electrochemical property and its phase composition,structure and morphology,characterized by X-ray diffraction （XRD）,transmission electron microscopy （TEM）and scanning electron microscopy （SEM）,were studied.The electrochemical performance of Cu2＋-doped samples at room and low temperature was also investigated.The results show that the carbon-coating composite LiFePO4/C （LFP/C）synthesized hydrothermally at 200℃ for 24 h is of specific capacity of 140.7 mAh·g-1 under discharge current density of 1C （150 mA·g-1）.The performance could be further improved after LFP200/C was doped by Cu2＋,i.e.the specific capacity was 150.3 mAh·g-1 and 108.7 mAh·g-1 at room temperature with discharge current density 1 C and 10 C,and 97 mAh·g-1 at-30℃,respectively.

关 键 词：Li3PO4 水热法 LIFEPO4 改性 

分 类 号：TM912.9[电气工程—电力电子与电力传动] O614.121[理学—无机化学]