Li^+在尖晶石钛酸盐Li_2ZnTi_3O_8中的电化学行为

Electrochemical performances of Li-ion in spinel titanate Li_2ZnTi_3O_8

采用溶胶-凝胶结合固相反应制备Li2ZnTi3O8负极材料,通过X线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)及恒电流充放电等手段表征Li2ZnTi3O8负极材料的微观结构和电化学性能。结果表明:Li2ZnTi3O8负极材料具有尖晶石结构特征。Li2ZnTi3O8负极材料在0.02～3 V能够完全可逆脱出与嵌入Li+;以30 mA/g的电流密度进行充放电,可逆充电比容量可达219.9 mA·h/g(是理论容量的96%),240 mA/g的电流密度下,其可逆比容量仍可达150 mA·h/g。首次循环之后尖晶石结构的Li2ZnTi3O8材料呈现出良好的循环稳定性。充放电过程中Li+的嵌入和脱出引起结构的变化是完全可逆的。

Li2ZnTi3O8 as an anode material for Li-ion battery was synthesized by a sol-gel process and solid-state reaction.The electrochemical properties and micro-structure of Li2ZnTi3O8 electrode material were investigated by X-ray diffraction（XRD）,field-emission scanning electron microscope（FESEM） and galvano charge-discharge analysis.The result indicated that Li2ZnTi3O8 had a spinel structure.Li2ZnTi3O8 electrode had a good electrochemical reversibility between 0.02 V and 3 V.The Li2ZnTi3O8 electrode had a reversible capacity of 219.9 mA·h/g at a charge current density of 30 mA/g,and showed a reversible capacity of 150 mA·h/g at a current density of 240 mA/g.The spinel type Li2ZnTi3O8 exhibited excellent cycling stability after the first cycle.The structure change was completely reversible during discharge and charge process.