Li_3PO_4掺杂的Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2锂离子电池正极材料的流变相法合成及电化学性能表征  

Synthesis of Li_3PO_4-doped Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 by rheological phase method and its electrochemical performance as cathode material for Li-ion batteries

作　　者：张睿[1] 吴元欣[1] 何云蔚[2] 艾常春[1] 

机构地区：[1]武汉工程大学化工与制药学院,湖北武汉430073 [2]武汉工程大学化学与环境工程学院,湖北武汉430073

出　　处：《化工学报》2015年第8期3177-3182,共6页CIESC Journal

摘　　要：采用氢氧化物共沉淀法制备了锂离子电池正极材料前驱体（Ni0.5Co0.2Mn0.3）（OH）2，并用流变相反应法合成了Li3PO4掺杂的Li（Ni0.5Co0.2Mn0.3）O2锂离子电池正极材料。运用X射线粉末衍射和恒电流充放电对产物进行了结构和电化学性能的表征，结果表明Li3PO4掺杂的Li（Ni0.5Co0.2Mn0.3）O2具有标准的层状α-NaFeO2结构，样品为1μm左右的片状一次颗粒聚集而成的类球形二次颗粒。掺杂1%（质量分数）Li3PO4的 Li（Ni0.5Co0.2Mn0.3）O2锂离子电池在0.1C的倍率下首次放电比容量达到188.6 mA·h·g-1（2.2～4.6 Vvs Li＋/Li），30次循环后容量保持率为92.9%。循环伏安、交流阻抗测试表明Li3PO4的掺杂可减少充放电过程中电解液和电极之间的电荷传递电阻和锂离子扩散电阻，减小极化作用，从而提升了Li（Ni0.5Co0.2Mn0.3）O2材料的电化学性能。LiNixCoyMnzO2 （0〈x〈1, 0〈y〈1, 0〈z〈1） has become prosperous materials for the next generation of rechargeable lithium ion battery due to the synergistic effect of the three elements and their higher discharge voltage platform and charge-discharge capacity, but the cycle stability still need to be improved. The Ni0.5Co0.2Mn0.3（OH）2precursor was synthesized by using the method of hydroxide co-precipitation and the lithium phosphate doped Li（Ni0.5Co0.2Mn0.3）O2powders prepared by rheological phase reaction. The crystal structure and electrochemical performance of Li3PO4 doped Li（Ni0.5Co0.2Mn0.3）O2powders were measured by X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDS）, galvanostatic charge-discharge, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. The result indicated that Li（Ni0.5Co0.2Mn0.3）O2doped with Li3PO4powders maintained the laminated structure ofα-type-NaFeO2, and the spherical powders were agglomerated with primary particles around 1μm. The initial discharge capacity of Li（Ni0.5Co0.2Mn0.3）O2powders doped with 1% （mass） Li3PO4 was 188.6 mA·h·g-1 （2.2—4.6 Vvs Li＋/Li）, and maintained 92.9% after 30 cycles at 0.1C. Moreover, CV results showed that oxidation and reduction potential of Li（Ni0.5Co0.2Mn0.3）O2 powders doped with 1% Li3PO4 were 3.98 and 3.64 V, the polarization of the sample was 0.34 V. The EIS tests showed that the charge transfer resistance and Warburg resistance of Li（Ni0.5Co0.2Mn0.3）O2powders doped with 1% Li3PO4 were 36.7 and 0.08661-. So that, Li3PO4 components can reduce the charge transfer resistance and＆nbsp;Li＋ diffusion resistance between electrode and electrolyte, and decrease the effect of polarization, thus promote the electrochemical performance of Li（Ni0.5Co0.2Mn0.3）O2.

关 键 词：流变相反应 合成 Li3PO4 掺杂 Li(Ni0.5Co0.2Mn0.3)O2 正极材料 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]