采用高温固相反应合成了Li2+2xTi1-xCux(NbO4)2,XRD分析表明:当x<0.8时均能得到与LiFePO4相同的橄榄石结构.电导率测定结果表明:x=0.6的合成物室温电导率最高,为1.26×10-5S/cm,且当x>0.6时合成物都表现出离子电导的特征.以x=0.6的合成物做成的待测电极与锂片组成电池,在1mol/L的LiPF6/EC+DMC(1:1)电解液中在0.5-4.6V间以0.10mA/cm2的电流密度进行电池循环测试的结果表明,该电池的首次放电比容量高达805.8mAh/g,放电平台在对Li+/Li电对为2V附近,但其可逆性及循环性均有待改善.
Li2+2xTi1-xCux(NbO4)_2 was prepared by high temperature solid state reaction. XRD analysis shows that a olivine structure of LiFePO_4 can be found in the composition range
of x≤0.8. A.C. impedance measurements show that the initial composition of x=0.6 possesses the best conductivity of 1.26×10-5 S/cm at room temperature, and that all samples with a
composition of x≥0.6 show the character of fast ion conductor. The sample with composition of x=0.6 was selected for electrode performance test, the results show that it has a very high
discharge specific capacity of 805.8mAh/g with a long discharge plateau at 2.0V during the first cycle in the voltage range of 0.5-4.6V vs Li+/Li at 0.10mA/cm2 rate in 1mol/L LiPF6/EC+DMC(1:1)
electrolyte and that its reversibility and cycle performance need to be improved.
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