摘要
以NH4VO3, Li2CO3为原料, 无水乙醇为介质, 采用一种新的固相法合成了Li1+xV3O8.运用TG/DSC, XRD, SEM等手段进行了表征, 测量了Li1+xV3O8的高温电导率, 求出了电导活化能;并研究了Li1+xV3O8的热稳定性.制备的Li1+xV3O8的形状为棒状和条状, 长端约10 μm, 短端约5 μm.热分析结果表明, 其结构不随温度改变而改变, 直到628 ℃熔化.在500 ℃时, 当电流密度为100 mA·cm-2时, Li1+xV3O8的峰值电压为2.77 V, 终止电压为1.8 V时, 比容量为198 mAh·g-1.室温～550 ℃, Li1+xV3O8的电导率和温度的关系式为lnσ=1.505～2.141×103/T, 说明在该温度区间Li1+xV3O8具有始终如一的电子跃迁机构, 其电导活化能为0.185 eV.
Li1＋xV3O8 was synthesized by means of a novel solid-state method, in which the materials were NH4VO3, Li2CO3 and absolute alcohol. The Li1＋xV3O8 powder was characterized by thermogravimetric analysis （TGA）/differential scanning calorimetry （DSC）, Xray diffraction （XRD） and scanning electron microscopy （SEM）. The high-temperature electrical conductivity, activated energy of electrical conductivity and thermal stability of Li1＋xV3O8 were measured. The shape of Li1＋xV3O8 is a stick or strip, of which the long end is about 10μm and the short end is about 5μm. The results of thermal analysis show that the structure does not change with the temperature until it melt at 628℃. The peak voltage of Li1＋xV3O8 is 2.77 V at 100 mA·cm^-2 and 500℃ and the specific capacity reaches 198 mAh·g^-1 at cut-off voltage of 1.8 V. From room temperature to 550℃, the formula of electrical conductivity of Li1＋xV3O8 and temperature is lnσ = 1.505 - 2. 141 ×10^3/T, which shows a consistant electron-transition mechanism for Li1＋xV3O8. Activated energy of electrical conductivity of Li1＋xV3O8 is 0. 185 eV.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2005年第5期685-689,共5页
Chinese Journal of Rare Metals
基金
国家自然科学基金资助项目(50002015)
关键词
LI1+XV3O8
合成
电化学
高温电导率
热稳定性
Li1＋xV3O8
synthesis
electrochemical
high-temperature electrical conductivity
thermal stability
