Mg、Ti离子复合掺杂改性磷酸铁锂正极材料及其电池性能  

Synthesis and Characterization of Mg and Ti Ions Co-Doped Lithium Iron Phosphate and Its Lithium-Ion Batteries

作　　者：王震坡[1] 刘文[2] 王悦[3] 赵春松 张淑萍 陈继涛[2] 周恒辉[2] 张新祥[2] 

机构地区：[1]北京理工大学电动车辆国家工程实验室,北京100081 [2]北京大学化学与分子工程学院,北京分子科学国家实验室,北京100871 [3]中国人民解放军防化学院,北京102205 [4]北大先行科技产业有限公司,北京102200

出　　处：《物理化学学报》2012年第9期2084-2090,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(61004092);国家高技术研究发展计划项目(863)(2009AA035200)资助~~

摘　　要：在氮气气氛下采用高温固相方法,合成了Mg、Ti离子复合掺杂改性的锂离子电池正极材料(Li0.98Mg0.01)(Fe0.98Ti0.01)PO4/C,并通过粉末X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和充放电循环对材料进行性能表征.测试结果表明,复合离子掺杂可显著改善材料的电化学性能,模拟电池在0.2C和1C倍率下的放电比容量分别为154.7和146.9mAh·g-1.以此复合掺杂样品为正极材料组装60Ah动力电池,其3C倍率放电容量仍保持为1C倍率放电容量的100%;低温0和-20℃测试条件下,动力电池放电容量分别保持为常温初始放电容量的89.7%和63.1%;在常温1C/1C充放电条件下,经过2000次循环后,电池容量依然保持为初始放电容量的89%,显示出优良的倍率放电性能和循环性能.研究结果表明,Mg、Ti离子复合掺杂改性的磷酸铁锂正极材料及其电池具有优良的放电性能和循环稳定性,可广泛应用于电动(或混合动力)汽车和储能电池系统.Mg and Ti ions co-doped （Li0.98Mg0.01）（Fe0.98Ti0.01）PO,/C cathode material for lithium-ion batteries was prepared by a solid-state method under N2 atmosphere. The samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and galvanostatic charge-discharge test. Results indicated that Mg and Ti ions co-doping remarkably improved the electrochemical performance of LiFePO4, including rate capacity, temperature behavior, and cycling stability. Discharge capacities of 154.7 and 146.9 mAh. g-1 were obtained at the rates of 0.2C and 1C for half-cell tests, respectively. For 60 Ah full-cell tests, 100% of 1C capacity was maintained even at 3C rate, 89.7% and 63.1% of initial capacity at room temperature were retained at 0 and -20 ℃, respectively. 89% capacity retention remained after 2000 cycles at room temperature, presenting excellent cycle stability. This investigation suggests that the present co-doping material and the resulting battery possess large discharge capacity and excellent cycling performance, making it applicable in electric vehicle （EV）/hybrid electric vehicle （HEV） and energy storage systems on a large scale.

关 键 词：磷酸铁锂 复合掺杂 倍率性能 动力电池 储能电池 

分 类 号：O646[理学—物理化学] TM912[理学—化学]