A new cathode material, LiVPO4F, has been synthesized through two steps of solid-state reactions. In the first step, vanadium pentoxide, ammonium dihydrogen phosphate, and a high surface area carbon were pre-heated at...A new cathode material, LiVPO4F, has been synthesized through two steps of solid-state reactions. In the first step, vanadium pentoxide, ammonium dihydrogen phosphate, and a high surface area carbon were pre-heated at 300 ℃ and reacted at 750 ℃ under an inert atmosphere to yield the trivalent vanadium phosphate VPO4. In the second step, the product LiVPO4F was synthesized by the reaction with VPO4 and LiF. The LiVPO4F was characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and charge/discharge testing measurements. The LiVPO4F is triclinic crystalline system. At 0.1 C rate, the first charge/discharge capacities were 150.1 mAh·g-1 and 132.6 mAh·g-1; At 0.2 C rate, the first charge/discharge capacities were 142.9 mAh·g-1 and 125.2 mAh·g-1. The LiVPO4F from this work has higher charge/discharge voltage 4.3 V and 4.1 V, respectively.展开更多
A high purity LiPF6 that has been widely used as lithium-ion secondary batteries electrolyte was prepared using acetonitrile as the medium. The target product was analyzed by FT-IR, TG-DTA and XRD, FT-IR. The results ...A high purity LiPF6 that has been widely used as lithium-ion secondary batteries electrolyte was prepared using acetonitrile as the medium. The target product was analyzed by FT-IR, TG-DTA and XRD, FT-IR. The results indicate the absorption brands of LiPF6 agreed reasonably with the theoretical predictions. TG-DTA showed that the decomposition of LiPF6 was in three steps in stead of one step.展开更多
以 L i2 CO3 和 NH4 VO3 为原料 ,低温合成了 L i1+ x V3 O8.通过对中间产物的热分析 ,选定了低温合成 L i1+ x V3 O8的适宜煅烧温度为 30 0℃ .研究表明 ,L i1+ x V3 O8,原料 L i/ V摩尔比应大于1∶ 3.以 Li1+ x V3 O8作为正极材料 ,...以 L i2 CO3 和 NH4 VO3 为原料 ,低温合成了 L i1+ x V3 O8.通过对中间产物的热分析 ,选定了低温合成 L i1+ x V3 O8的适宜煅烧温度为 30 0℃ .研究表明 ,L i1+ x V3 O8,原料 L i/ V摩尔比应大于1∶ 3.以 Li1+ x V3 O8作为正极材料 ,金属锂为负极组装了模拟电池 ,高、低温合成材料具有较高的放电容量和放电电压 .XRD、SEM分析结果说明低温合成样品的结晶度低、粒径较小 .展开更多
以LiOH溶液和不同粒径的自制球形TiO2为反应物,通过水热法快速地合成了尖晶石型结构的球形Li4Ti5O12,并考察了材料合成的水热反应机理和电化学性能。TiO2在100℃、5 mol/L Li OH溶液中经水热反应20 h得到前驱体,再经800℃热处理2 h便可...以LiOH溶液和不同粒径的自制球形TiO2为反应物,通过水热法快速地合成了尖晶石型结构的球形Li4Ti5O12,并考察了材料合成的水热反应机理和电化学性能。TiO2在100℃、5 mol/L Li OH溶液中经水热反应20 h得到前驱体,再经800℃热处理2 h便可得到粒径大小不同（0.5-1.5μm）且分布均匀的球形尖晶石Li4Ti5O12材料。Li OH在水热反应条件下扩散到球形TiO2内部,得到在分子水平混合均匀的Li-Ti-O中间体,利于高温下生成纯相的尖晶石Li4Ti5O12。所得粒径大小不同的Li4Ti5O12材料均表现出稳定的电化学循环充放电性能,其中,粒径为0.5μm的Li4Ti5O12材料的电化学性能最好：室温下,以0.2 C的倍率进行充放电,其可逆容量达到158 m Ah/g,70周后容量保持率高于99%;同时还表现出优异的高温循环稳定性,55℃下以0.2 C的倍率进行充放电,50次循环后其可逆放电比容量仍能达到125 m Ah/g。展开更多
Cathode material LiVPO4Cl for lithium-ion rechargeable batteries was synthesized by one-step hydro-thermal method. The result of XRD measurement shows that LiVPO4Cl material has a triclinic crystal structure,P1 space ...Cathode material LiVPO4Cl for lithium-ion rechargeable batteries was synthesized by one-step hydro-thermal method. The result of XRD measurement shows that LiVPO4Cl material has a triclinic crystal structure,P1 space group; the results of SEM and TEM indicate that the sample is mostly single-crystalline,stick-like material; and the results of charge/discharge testing and cyclic voltammetry measurement demonstrate that the charging plateau of LiVPO4Cl material maintains at 4.02 V and the discharging plateau at 3.86 V. After sufficient activation,the discharge capacity at 0.1C rate of the fortieth cycle of LiVPO4Cl material with relatively higher content of carbon reaches 101 mAh·g-1.展开更多
文摘A new cathode material, LiVPO4F, has been synthesized through two steps of solid-state reactions. In the first step, vanadium pentoxide, ammonium dihydrogen phosphate, and a high surface area carbon were pre-heated at 300 ℃ and reacted at 750 ℃ under an inert atmosphere to yield the trivalent vanadium phosphate VPO4. In the second step, the product LiVPO4F was synthesized by the reaction with VPO4 and LiF. The LiVPO4F was characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and charge/discharge testing measurements. The LiVPO4F is triclinic crystalline system. At 0.1 C rate, the first charge/discharge capacities were 150.1 mAh·g-1 and 132.6 mAh·g-1; At 0.2 C rate, the first charge/discharge capacities were 142.9 mAh·g-1 and 125.2 mAh·g-1. The LiVPO4F from this work has higher charge/discharge voltage 4.3 V and 4.1 V, respectively.
文摘A high purity LiPF6 that has been widely used as lithium-ion secondary batteries electrolyte was prepared using acetonitrile as the medium. The target product was analyzed by FT-IR, TG-DTA and XRD, FT-IR. The results indicate the absorption brands of LiPF6 agreed reasonably with the theoretical predictions. TG-DTA showed that the decomposition of LiPF6 was in three steps in stead of one step.
文摘以 L i2 CO3 和 NH4 VO3 为原料 ,低温合成了 L i1+ x V3 O8.通过对中间产物的热分析 ,选定了低温合成 L i1+ x V3 O8的适宜煅烧温度为 30 0℃ .研究表明 ,L i1+ x V3 O8,原料 L i/ V摩尔比应大于1∶ 3.以 Li1+ x V3 O8作为正极材料 ,金属锂为负极组装了模拟电池 ,高、低温合成材料具有较高的放电容量和放电电压 .XRD、SEM分析结果说明低温合成样品的结晶度低、粒径较小 .
文摘以LiOH溶液和不同粒径的自制球形TiO2为反应物,通过水热法快速地合成了尖晶石型结构的球形Li4Ti5O12,并考察了材料合成的水热反应机理和电化学性能。TiO2在100℃、5 mol/L Li OH溶液中经水热反应20 h得到前驱体,再经800℃热处理2 h便可得到粒径大小不同（0.5-1.5μm）且分布均匀的球形尖晶石Li4Ti5O12材料。Li OH在水热反应条件下扩散到球形TiO2内部,得到在分子水平混合均匀的Li-Ti-O中间体,利于高温下生成纯相的尖晶石Li4Ti5O12。所得粒径大小不同的Li4Ti5O12材料均表现出稳定的电化学循环充放电性能,其中,粒径为0.5μm的Li4Ti5O12材料的电化学性能最好：室温下,以0.2 C的倍率进行充放电,其可逆容量达到158 m Ah/g,70周后容量保持率高于99%;同时还表现出优异的高温循环稳定性,55℃下以0.2 C的倍率进行充放电,50次循环后其可逆放电比容量仍能达到125 m Ah/g。
文摘Cathode material LiVPO4Cl for lithium-ion rechargeable batteries was synthesized by one-step hydro-thermal method. The result of XRD measurement shows that LiVPO4Cl material has a triclinic crystal structure,P1 space group; the results of SEM and TEM indicate that the sample is mostly single-crystalline,stick-like material; and the results of charge/discharge testing and cyclic voltammetry measurement demonstrate that the charging plateau of LiVPO4Cl material maintains at 4.02 V and the discharging plateau at 3.86 V. After sufficient activation,the discharge capacity at 0.1C rate of the fortieth cycle of LiVPO4Cl material with relatively higher content of carbon reaches 101 mAh·g-1.
