Li4Ti5O12/NiO复合材料的制备及其电化学性能

摘要

以Li4Ti5O12,Ni(NO3)2·6H2O和NH4HCO3为原料,采用化学沉积法与热分解法相结合制备一系列Li4Ti5O12/NiO复合材料.通过X线衍射仪、扫描电镜和X线能谱仪对所得材料进行物理结构、形貌和成分分析,采用恒流充放电和循环伏安测试研究材料的电化学性能.结果表明,Li4Ti5O12/NiO (5％)复合材料具有最佳的循环可逆性能,适量的NiO可有效改善材料的电化学性能.在2.5～0.1 V的电压范围和30 mA/g的电流密度下,30次循环后,Li4Ti5O12/NiO(5％)复合材料具有最佳的放电比容量为228.3 mA·h/g,与Li4Ti5O12相比,提高了23.8 mA·h/g;Li4Ti5O12/NiO(5％)复合材料中的NiO没有阻碍电极反应中锂离子的迁移,且提高了Li4Ti5O12电极材料的电导率,降低了电极的极化.%A series of Li4Ti5O12/NiO composite materials were prepared by chemical deposition combined with thermal decomposition of a mixture of Li4Ti5O12 Ni(NO3)2-6H2O and NH4HCO3. The composite material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS), galvanostatic charge-discharge test and cyclic voltammetery(CV). The results show that Li4Ti5O12/NiO(5%) presents the best performance among all the samples, and proper coating can efficiently improve the electrochemical performance of Li4Ti5O12. The discharge capacity of Li4Ti5O12/NiO(5%) is 228.3 mA-h/g at the discharge/charge current density of 30 mA/g and the voltage range of 2.5-0.1 V after 30 cycles, which is 23.8 mA-h/g higher than that of pristine Li4TiO12. NiO does not inhibit the migration of lithium ions during the electrode reaction of Li4Ti5O12/NiO(5%) composite, and meanwhile it increases the conductivity and decreases the electrode polarization of Li4Ti5O12.