梯度包覆镍酸锂材料Li[Ni_(0.92)Co_(0.04)Mn_(0.04)]O_2的合成与研究  

Research on Synthesis and Performance of Composite Cathode Material Li[Ni_(0.92)Co_(0.04)Mn_(0.04)]O_2 with Gradient-Coating Layer as Lithium Ion Battery

作　　者：杜柯[1] 黄金龙[1] 胡国荣[1] 彭忠东[1] 曹雁冰[1] 潭潮溥[1] 王伟刚[1] 

机构地区：[1]中南大学冶金科学与工程学院,长沙410083

出　　处：《无机化学学报》2013年第5期1031-1036,共6页Chinese Journal of Inorganic Chemistry

基　　金：中央高校基本科研业务费(No.2012QNZT018)资助项目

摘　　要：采用浓度梯度加料的方式，首先沉淀制备了核为Ni（OH）2、壳为镍钴锰氢氧化物浓度梯度包覆的复合前驱体，然后配锂高温焙烧，合成了梯度包覆的镍酸锂复合正极材料Li[Ni0.92Co0.04Mn0.04]O2采用X射线衍射（XRO）、扫描电镜（SEM）、恒电流充放电测试等方法对材料的结构、表观形貌及电化学性能进行了表征。结果表明，该材料具有良好的六方单相层状a-NaFeO2结构．呈类球型状。切面元素线扫描显示该材料的包覆壳层中主要金属元素呈梯度变化。同时该新型梯度包覆的镍酸锂复合正极材料表现出了优越的电化学性能：在25℃下，2．8～4．3V充放电范围，0．1C首次放电比容量可达198．3mAh．g-1，循环40次容量保持96．8％；1C和2C倍率下放电比容量可达175mAh·g-1和165．1mAh·g-1。55℃下，该材料首次放电比容量可达236．1mAh．g-1，循环40次容量仍能保持77．5％．A new core-shell structure precursor were prepared by a co-precipitation method. A gracllent concentration of Ni-Co-Mn shell layer was co-precipitated on the Ni（OH）2 core which was used as the precursor. Then, the well-ordered spherical LiNi0.92Co0.04Mno.0402 was synthesized by sintering the mixture of as-prepared precursor and LiOH ＂H20 in 02. The prepared samples were characterized by X-ray diffractomet, SEM and galvanostatie charge-discharge test. The results show that, the product has a layered hexagonal a-NaFeO2 structure and a spherical morphology. The line scan test of elements on the cross section area of coating shell show that the main elements of the materials change gradiently. The initial discharge capacity is 193.8 mAh＇g-t at 0.1C rate between 2.8 and 4.3 V and retains 96.8% after 40 cycles at 25℃. The capacity at 1C and 2C is 175 mAh .g-1 and 165.1 mAh .g-1 When cycled at 55 ℃, the initial discharge capacity is 236.1 mAh ,g-1 and retains 77.5% after 40 cycles, indicating good electrochemical capacity and cycling stability.

关 键 词：锂离子电池 镍酸锂 梯度包覆 过渡金属氧化物 

分 类 号：TM912.9[电气工程—电力电子与电力传动]