通过水热法制备了稀土钆、钇离子掺杂的LiFe_(1-x)Gd_xPO_4、LiFe_(1-x)Y_xPO_4(x=0,0.01,0.03,0.05)锂离子电池正极材料,通过X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)等方法表征,对电池进行恒流充放电、交流阻抗(EIS)、循环伏安(CV)...通过水热法制备了稀土钆、钇离子掺杂的LiFe_(1-x)Gd_xPO_4、LiFe_(1-x)Y_xPO_4(x=0,0.01,0.03,0.05)锂离子电池正极材料,通过X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)等方法表征,对电池进行恒流充放电、交流阻抗(EIS)、循环伏安(CV)电化学测试,系统的研究了LiFePO_4微观结构及电化学性能。结果表明,通过水热法制备的少量稀土掺杂的磷酸铁锂正极材料仍然是橄榄石结构,颗粒尺寸300~800 nm,一定程度上细化颗粒有效的减小Li^+的扩散和迁移途径,增加了Li^+的占位无序度,使得锂离子脱嵌变得容易,改善了材料的电导性,使LiFePO_4正极材料放电比容量增加,循环稳定性能提高。在电位范围2.0~4.2 V之间,样品随着掺杂量的增加,初始放电比容量首先升高然后下降,其中LiFe_(0.97)Gd_(0.03)PO_4初始放电率达到143.38 m Ah/g,LiFe_(0.97)Y_(0.03)PO_4初始放电率达到148.35 m Ah/g,和空白样比提高了近45%,且EIS和CV测试结果进一步验证了LiFe_(0.97)Gd_(0.03)PO_4、LiFe_(0.97)Y_(0.03)PO_4样品具有最佳的电化学性能。展开更多
In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows: Firstly, potassium...In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows: Firstly, potassium carbonate, titanium dioxide and proper gadolinium oxide （dopant） were calcined in the muffle at high temperature and the doped gadolinium K2Ti4O9 fibres were obtained; secondly, the fibre was heated using glycerol as solvent until Gd-doped TiO2 nanofibres were obtained. The synthesized samples were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that Gd-doped TiO2 nanofibre heat-treated by glycerol solvent can inhibit the agglomeration, so the grain diameter of the fibre is smaller than that without heat-treated with glycerol. Meanwhile, the diameter of the fibre decreases with the increase of the heating temperature and time. 97% 98% of Gd-doped TiO2 nanofibre is anatase. The photocatalysis results showed that the photocatalysis activity of Gd-doped TiO2 nanofibre is just a little lower than that of TiO2 powder.展开更多
文摘通过水热法制备了稀土钆、钇离子掺杂的LiFe_(1-x)Gd_xPO_4、LiFe_(1-x)Y_xPO_4(x=0,0.01,0.03,0.05)锂离子电池正极材料,通过X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)等方法表征,对电池进行恒流充放电、交流阻抗(EIS)、循环伏安(CV)电化学测试,系统的研究了LiFePO_4微观结构及电化学性能。结果表明,通过水热法制备的少量稀土掺杂的磷酸铁锂正极材料仍然是橄榄石结构,颗粒尺寸300~800 nm,一定程度上细化颗粒有效的减小Li^+的扩散和迁移途径,增加了Li^+的占位无序度,使得锂离子脱嵌变得容易,改善了材料的电导性,使LiFePO_4正极材料放电比容量增加,循环稳定性能提高。在电位范围2.0~4.2 V之间,样品随着掺杂量的增加,初始放电比容量首先升高然后下降,其中LiFe_(0.97)Gd_(0.03)PO_4初始放电率达到143.38 m Ah/g,LiFe_(0.97)Y_(0.03)PO_4初始放电率达到148.35 m Ah/g,和空白样比提高了近45%,且EIS和CV测试结果进一步验证了LiFe_(0.97)Gd_(0.03)PO_4、LiFe_(0.97)Y_(0.03)PO_4样品具有最佳的电化学性能。
文摘In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows: Firstly, potassium carbonate, titanium dioxide and proper gadolinium oxide （dopant） were calcined in the muffle at high temperature and the doped gadolinium K2Ti4O9 fibres were obtained; secondly, the fibre was heated using glycerol as solvent until Gd-doped TiO2 nanofibres were obtained. The synthesized samples were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that Gd-doped TiO2 nanofibre heat-treated by glycerol solvent can inhibit the agglomeration, so the grain diameter of the fibre is smaller than that without heat-treated with glycerol. Meanwhile, the diameter of the fibre decreases with the increase of the heating temperature and time. 97% 98% of Gd-doped TiO2 nanofibre is anatase. The photocatalysis results showed that the photocatalysis activity of Gd-doped TiO2 nanofibre is just a little lower than that of TiO2 powder.
