采用溶胶-凝胶法和化学沉积法制备了Li4Ti4.75Cu0.25O12/SnO2复合活性材料。通过X射线衍射（XRD）、扫描电镜（SEM）、恒流充放电测试对材料进行结构、形貌表征及电化学性能测试。结果表明：Li4Ti4.75Cu0.25O12/SnO2复合活性物质能够进...采用溶胶-凝胶法和化学沉积法制备了Li4Ti4.75Cu0.25O12/SnO2复合活性材料。通过X射线衍射（XRD）、扫描电镜（SEM）、恒流充放电测试对材料进行结构、形貌表征及电化学性能测试。结果表明：Li4Ti4.75Cu0.25O12/SnO2复合活性物质能够进一步改善倍率性能的同时,循环性能也得到了很好的保证。当电压在1~3 V时,电流密度为1C倍率条件下,Li4Ti4.75Cu0.25O12/SnO2复合材料首次放电比容量高达202.55 m A·h/g。经过50次循环后,容量仍保持在202.51 m A·h/g,容量保持率高达99.98%。展开更多
Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increa...Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increasing the lithium content. SEM revealed that the morphology of particles changed from rounded polyhedral-like crystallites to sharp-edged polyhedral crystals with more doped lithium. EDX showed that the stoichiometries of Ni and Co agrees with calculated synthesized values. Electrochemical studies revealed the overlithiated samples have improved capacities as well as cycling behavior. The sample with x = 0.05 shows the best performance with a specific capacity of 113.29 mA.h.g-1 and the best capacity retention of 92.2% over 10 cycles. XPS results showed that the binding energy of Li ls is decreased for the Li doped samples with the smallest value for the x = 0.05 sample, implying that Li＋ ions can be extracted more easily from Li1.05Ni0.8Co0.2O2 than the other stoichiometries accounting for the improved performance of the material. Considerations of core level XPS peaks for transition metals reveal the existence in several oxidation states. However, the percentage of the＋3 oxidation state of transition metals for the when x = 0.1 is the highest and the availability for charge transition from the ＋3 to＋4 state of the transition metal during deintercalation is more readily available.展开更多
文摘采用溶胶-凝胶法和化学沉积法制备了Li4Ti4.75Cu0.25O12/SnO2复合活性材料。通过X射线衍射（XRD）、扫描电镜（SEM）、恒流充放电测试对材料进行结构、形貌表征及电化学性能测试。结果表明：Li4Ti4.75Cu0.25O12/SnO2复合活性物质能够进一步改善倍率性能的同时,循环性能也得到了很好的保证。当电压在1~3 V时,电流密度为1C倍率条件下,Li4Ti4.75Cu0.25O12/SnO2复合材料首次放电比容量高达202.55 m A·h/g。经过50次循环后,容量仍保持在202.51 m A·h/g,容量保持率高达99.98%。
文摘Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increasing the lithium content. SEM revealed that the morphology of particles changed from rounded polyhedral-like crystallites to sharp-edged polyhedral crystals with more doped lithium. EDX showed that the stoichiometries of Ni and Co agrees with calculated synthesized values. Electrochemical studies revealed the overlithiated samples have improved capacities as well as cycling behavior. The sample with x = 0.05 shows the best performance with a specific capacity of 113.29 mA.h.g-1 and the best capacity retention of 92.2% over 10 cycles. XPS results showed that the binding energy of Li ls is decreased for the Li doped samples with the smallest value for the x = 0.05 sample, implying that Li＋ ions can be extracted more easily from Li1.05Ni0.8Co0.2O2 than the other stoichiometries accounting for the improved performance of the material. Considerations of core level XPS peaks for transition metals reveal the existence in several oxidation states. However, the percentage of the＋3 oxidation state of transition metals for the when x = 0.1 is the highest and the availability for charge transition from the ＋3 to＋4 state of the transition metal during deintercalation is more readily available.
