采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、电池性能测试系统研究了多元稀土掺杂锂锰氧正极材料的相结构、形貌,并对其活化性能、循环稳定性能进行了表征.结果表明:采用Pechini法合成多元稀土掺杂LiMn_2O_4样品时,只有将掺杂元素的含量严格控制在一定范围内,所合成的LiMn_2O_4、LiLa0.03Mn1.97O4、LiLa_(0.012)Ce_(0.012)Mn_(1.976)O_4、LiLa_(0.012)Nd_(0.012)Mn_(1.976)O_4、LiCe_(0.012)Nd_(0.012)Mn_(1.976)O_4样品才具有纯尖晶石型LiMn_2O_4结构.当稀土掺杂元素含量较高时,所合成的LiLa0.015Ce0.015Mn1.97O4、LiLa0.015Nd0.015Mn1.97O4、LiCe0.015Nd0.015Mn1.97O4样品由LiMn_2O_4相及微量杂质相CeO_2、Nd_2O_3、CeO_2+Nd_2O_3组成.所有样品呈规则的近球形或球形,其粒径范围为0.5～2.8 μm.适量的稀土元素掺杂将使LiMn_2O_4材料的初始容量减小、充放电效率及循环稳定性能增加,LiCe_(0.012)Nd_(0.012)Mn_(1.976)O_4样品具有较好的综合电化学性能,其初始容量为123.5 mAh/g,经30次循环充放电后的容量为113.2 mAh/g,为相同条件下LiMn_2O_4样品放电容量的1.27倍.
The phase structure, the morphology, activation performance and cycle stability of the rare-earth-doped lithium manganese oxygen cathode materials prepared by Pechini process were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and battery testing system. The results show that the prepared LiMn_2O_4, LiLa_(0.03)Mn_(1.97)O_4, LiLa0.012Ce0.012Mn_(1.976)O_4, LiLa0.012Nd_(0.012)Mn_(1.976)O_4 and LiCe_(0.012)Nd_(0.012)Mn_(1.976)O_4 samples are composed of single-phase spinel LiMn_2O_4 structure only when the content of rare earth is strictly controlled in a certain range. The LiLa_(0.015)Ce_(0.015)Mn1.97O4, LiLa_(0.015)Nd_(0.015)Mn1.97O4 and LiCe_(0.015)Nd_(0.015)Mn1.97O4 specimens consist of the LiMn_2O_4 and trace CeO_2, Nd_2O_3, CeO_2+Nd_2O_3 phases when the content of the rare earth exceeds the range. The particles of all the specimens are regularly spheroid or near-sphere, and the size of the particles is 0.5-2.8 μm. The initial discharge capacity of the specimens would be decreased, and the ratio of discharge/charge capacity and cyclic stability of the specimens would be increased with the suitable rare earth element doping. The LiCe_(0.012)Nd_(0.012)Mn_(1.976)O_4 cathode materials has good comprehensive electrochemical performances whose initial discharge capacity is 123.5 mAh/g, and whose capacity is 113.2 mAh/g after the 30th cycle, 1.27 times as high as that of LiMn_2O_4 material.
参考文献
| [1] | Yang S T;Jia J H;Ding L et al.[J].Journal of Electrochimica Acta,2003,48:569. |
| [2] | Dsa S R;Fachini I R;Majumder S B et al.[J].Journal of Power Sources,2006,158:524. |
| [3] | 刘心宇,吕罡,蒙冕武.合成条件对尖晶石型LixMn2O4正极材料结构的影响[J].湖南科技大学学报（自然科学版）,2007(03):31-34. |
| [4] | 姚耀春,戴永年,杨斌,马文会.超声空化预处理对尖晶石LiMn2O4性能的影响[J].电池,2007(02):83-85. |
| [5] | 李国防,凌翠霞,马淮凌,乔庆东.溶胶-凝胶-微波法制备阴阳离子同时掺杂型LixMn2OyFz[J].化学研究与应用,2006(02):160-164. |
| [6] | Shen P Z;Jia D Z;Huang Y D et al.[J].Journal of Power Sources,2006,158:608. |
| [7] | 肖劲,曾雷英,彭忠东,赵浩,胡国荣.锂离子电池正极材料LiNi0.5Mn0.5O2的循环性能[J].中国有色金属学报,2006(08):1439-1444. |
| [8] | Kim G H;Myung S T;Bang H J et al.[J].Electrochemical and Solid-State Letters,2004,7(12):477. |
| [9] | Son J T;Kim H G .[J].Journal of Power Sources,2005,147:220. |
| [10] | Nakmura T;Kajiyama A .[J].Solid State Ionics,2000,133(3-4):195. |
| [11] | 童庆松,杨勇,连锦明.掺钛电解二氧化锰制掺杂LiMn2O4的电化学性能[J].无机化学学报,2005(12):1784-1790. |
| [12] | 孙继红,范文浩,吴东,孙予罕.溶胶-凝胶（Sol-gel）化学及其应用[J].材料导报,2000(04):25-29. |
| [13] | 夏君磊,赵世玺,刘韩星,欧阳世翕.F掺杂影响LiMn2O4性能的机理研究[J].功能材料,2004(01):74-76. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%