纳米MgO掺杂改善LiNi(1/3)Co(1/3)Mn(1/3)O2正极材料  

Improvement of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 Cathode Materials by Nano-MgO Doping

作　　者：李节宾[1,2] 徐友龙[1] 熊礼龙[1] 王景平[1] 

机构地区：[1]西安交通大学电子陶瓷与器件教育部重点实验室,国际电介质研究中心,西安710049 [2]陕西应用物理化学研究所,西安710061

出　　处：《物理化学学报》2011年第11期2593-2599,共7页Acta Physico-Chimica Sinica

摘　　要：将氢氧化物共沉淀法制备的(Ni_(1/3)Co_(1/3)Mn_(1/3))(OH)_2在500℃热处理5 h得到具有尖晶石结构、纳米尺寸的氧化物M_3O_4(M=Ni_(1/3)Co_(1/3)Mn_(1/3)).将其与LiOH及不同量的纳米MgO混合均匀,并在850℃热处理24 h制备了Li(Ni_(1/3)Co_(1/3)Mn_(1/3))_(1/x)Mg_xO_2(x=0,0.01,0.02,0.03,0.04,0.05)正极村料.随着Mg掺杂量的增大,正极材料的晶胞参数增大;少量的Mg掺杂增大了锂离子的扩散系数,而过度掺杂却使锂离子扩散系数有所降低,其中Li(Ni_(1/3)Co_(1/3)Mn_(1/3))_(0.98)Mg_(0.02)O_2的锂离子扩散系数最大,其脱出和嵌入扩散系数分别为D_(Li-dein)=29.20×10^(-11)cm^2·S^(-1)和D_(Li-in)=4.760×10^(-11)cm^2·s^(-1);其以3C倍率充放电的平均放电比容量为139.3 mAh·g^(-1),比未掺杂的原粉约高9.5 mAh·g^(-1);另外其循环性能也得到了大幅度改善.Nano-sized M_3O_4（M=Ni_（1/3）CO_（1/3）Mn_（1/3）） powder with a spinel structure was prepared by sintering co-precipitated M（OH）_2 at 500℃for 5 h.The so-obtained M_3O_4 was then mixed with LiOH and different amounts of nano-MgO.The mixture was sintered at 850℃for 24 h to synthesize Li（Ni_（1/3）Co_（1/3）Mn_（1/3））_（1-x）Mg_xO_2 （x=0,0.01,0.02,0.03,0.04,0.05） cathode materials.The lattice parameters increased while the diffusion coefficients of Li~＋ ion showed an increasing and then decreasing trend with an increase in the amount of Mg substitution.Li（Ni_（1/3）Co_（1/3）Mn_（1/3））_（0.98）Mg_（0.02）O_2 had the highest Li~＋ ion diffusion coefficients,which were 29.20×10^（-11） cm^2·s^（-1） for Li~＋ de-intercalation and 4.760×10^（-11） cm^2·s^（-1） for Li~＋ intercalation.Its discharge capacity at 3C rate was 139.3 mAh·g^（-1）,which is 9.5 mAh·g^（-1） higher than that of the pristine material.Furthermore,its cycle performance was also improved significantly compared with the un-doped counterpart.

关 键 词：锂离子电池 正极材料 LiNi(1/3)Co(1/3)Mn(1/3)O2 Mg掺杂 锂离子扩散系数 

分 类 号：TM912[电气工程—电力电子与电力传动]