【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10μm,短端约5μm。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。更多还原

【Abstract】 Li_1+xV₃O₈ was synthesized by means of a novel solid-state method,in which the materials were NH₄VO₃,Li₂CO₃ and absolute alcohol.The Li_1+xV₃O₈ powder was characterized by thermogravimetric analysis（TGA）/differential scanning calorimetry（DSC）,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The high-temperature electrical conductivity,activated energy of electrical conductivity and thermal stability of Li_1+xV₃O₈ were measured.The shape of Li_1+xV₃O₈ is a stick or strip,of which the long end is about（10 μm） and the short end is about（5 μm）.The results of thermal analysis show that the structure does not change with the temperature until it melt at 628 ℃.The peak voltage of Li_1+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 Li_1+xV₃O₈ and temperature is lnσ=1.505-2.141×10³/T,which shows a consistant electron-transition mechanism for Li_1+xV₃O₈.Activated energy of electrical conductivity of Li_1+xV₃O₈ is 0.185 eV.更多还原