摘要
以Li2CO3和粒径为70nm的TiO2为原料,以碱式碳酸镁[(MgCO3)4·Mg(OH)2·6H2O]为镁源,采用高温固相法合成了Li4Mgx Ti5O12(设定镁锂摩尔比R=x/4=0.01、0.02、0.03、0.04、0.05来确定掺杂镁的量)。采用XRD、SEM、CV、电化学阻抗谱、充放电曲线等对所合成的材料进行了物理和电化学性能表征。测试结果表明:随着Mg2+掺杂量的增加,钛酸锂的比容量出现先增大后减小的趋势;当R=0.03时具有最高的电化学性能,其首次放电比容量高达189.9mAh/g,高于Li4Ti5O12的理论容量175mAh/g。由于适量的Mg2+掺杂改善了材料的内部结构,提高了锂离子的嵌入量从而提高了比容量。
Mg-doped Li4 MgxTi5 O12 （R = x/4 = 0.01,0. 02,0. 03,0. 04,0. 05） have been prepared by solid-state reaction with stoichiometric mixing of Li2CO3, TiO2 （70 nm） and （MgCOa）4 · Mg（OH）2 · 6H2O and examined by XRD, SEM and electrochemical measurements. The results showed that the specific capacity of Li4 Mgy Ti5 O12 was increased gradually at first and then decreased with the increasing of the Mg-doped amount. Li4 MgyTi5 O12 （R=0. 03） exhibited the highest specific capacity of 189.9 mAh/g, which was higher than the theory capacity of Li4 Ti5 O12 without doping Mg2＋. Therefore, the enhancement of the electrochemical performance can be attributed to Mg-doping which enhanced the conductivity of the materials.
出处
《化工新型材料》
CAS
CSCD
北大核心
2014年第1期93-95,99,共4页
New Chemical Materials
基金
国家自然科学基金(21273058)
中国博士后科学基金(2012M520731)
关键词
锂离子电池
负极材料
LI4TI5O12
碱式碳酸镁
Lithium ionic battery, cathode material, Li4 Ti5 O12, alkali type magnesium carbonate
