高能量密度LiMn2O4微球的制备及其电化学性能研究

 全文下载：2014010018

姚元路， 李桂村*

（青岛科技大学  材料科学与工程学院， 山东 青岛 266042）

 摘要： 采用控制结晶法制备的球形MnCO3前驱体与Li2CO3在高温煅烧条件下进行固相反应合成了高能量密度尖晶石型LiMn2O4微球。通过扫描电子显微镜对不同反应时间形成的球形MnCO3产物观察表明，球形MnCO3前驱体是由许多小粒子通过静电作用力组装而成的球形微米二次粒子，其形成经历了一个成核聚结的过程。球形MnCO3前驱体经高温锂化后可以直接获得高振实密度的LiMn2O4微球（18 g·cm-3），煅烧前后形貌未发生明显改变。LiMn2O4微球在常温和高温（55 ℃）条件下的电化学性能测试表明，在05 C (1 C=148 mA·g-1)倍率时，常温下的首次充放电比容量分别为1173和1160 mAh·g-1，充放电能量密度分别为4808和4620 Wh·kg-1，50次循环后的放电能量密度保持率为988%；高温下的首次充放电比容量分别为1196和1156 mAh·g-1，充放电能量密度分别为4876和4629 Wh·kg-1，50次循环后的放电能量密度保持率仍达到923%。

关键词： 锂离子电池； 正极材料； 微球； LiMn2O4

中图分类号： TM 912.9   文献标志码： A

Preparation and Electrochemical Properties of LiMn2O4Microspheres with High Energy Density

 YAO Yuanlu, LI Guicun

(College of Materias Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China)

Abstract: Spinel LiMn2O4 microspheres have been synthesized via the solid state reaction between spherical MnCO3 precursor obtained by controlled crystallization method and Li2CO3 by calcination at high temperature. Scanning electron microscopy images of spherical MnCO3 precursor formed at different reaction time reveal that spherical MnCO3 secondary particles tends to be formed by agglomeration of small seeds due to the electrostatic force between the seed particles. The formation of spherical MnCO3 precursor undergoes a nucleationagglomeration process. LiMn2O4 microspheres synthesized by high temperature lithiation of spherical MnCO3 precursor show high tap density (18 g·cm-3). The spherical morphologies are retained before and after calcination. The electrochemical properties of LiMn2O4 microspheres at room temperature and high temperature (55 ℃) were measured. At room temperature, its initial charge/discharge specific capacities are 1173 and 1160 mAh·g-1 at 05 ℃, respectively. The corresponding charge/discharge energy densities are 480.8 and 4620 Wh·kg-1, respectively. The cycling discharge specific capacity retention is 988% after 50 cycles. At 55 ℃， the initial charge/discharge capacities are 1196 and 1156 mAh·g-1 at 05 ℃ (4876 and 4629 Wh·kg-1), respectively. The cycling discharge specific capacity retention is 923% after 50 cycles.

Key words: Liion batteries; cathode materials; microspheres; LiMn2O4

收稿日期： 20121105

作者简介：姚元路（1986—），男，硕士研究生.*通信联系人.