Iron disulfide(FeS_2)cathode active material was prepared from iron and sulfur at room temperature by high energy mechanical alloying.Modified FeS_2 composites containing Co or Ni transition metal powders as additives...Iron disulfide(FeS_2)cathode active material was prepared from iron and sulfur at room temperature by high energy mechanical alloying.Modified FeS_2 composites containing Co or Ni transition metal powders as additives were also prepared by the same method.Lithium cells with these FeS_2 cathodes were studied for charge-discharge properties at room temperature using 0.5M LiTFSI in tetra(ethylene glycol)dimethyl ether(TEGDME)solvent.Cyclic voltammetry showed two anodic oxidation peaks at 1.8 and 2.5V and two cathodic reduction peaks at 2.0 and 1.3 V for FeS_2 with metal additives.The addition of 5wt% Co and 3wt% Ni resulted in an enhancement of the first discharge capacity giving 571 and 844mAh/g respectively at 0.1C-rate.The cycle performance was also enhanced remarkably by the addition of these electrically conductive transition metals in the active material.FeS_2 with 5wt% Co exhibited a stable cycle performance delivering a reversible capacity of 338mAh/g(37.8% of theoretical capacity)after 20 cycles.展开更多
Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assis...Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst.In this work,Gallium oxide(β-Ga_2O_3)nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700-1000℃ using the iron,nickel,copper,cobalt and zinc oxide as a catalyst,respectively.The β-Ga_2O_3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850,900 and 950℃ in all the catalysts.But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst.As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods,and its diameter increased.From these results,we could be proposed that the growth mechanism of β-Ga_2O_3 nanowires was changed with synthesis temperature of nanowires.Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM,FE-SEM,EDX and XRD.展开更多
In order to investigate the possibility of Si thin film as an anode for Na battery,we studied the electrochemical intercalation of sodium into the Si film.Amorphous Si thin film electrode was prepared using DC magnetr...In order to investigate the possibility of Si thin film as an anode for Na battery,we studied the electrochemical intercalation of sodium into the Si film.Amorphous Si thin film electrode was prepared using DC magnetron sputtering.Sodium ion could intercalate into Si thin film upto Na0.52Si,i.e.530mAh·g-1-Si.The first discharge capacity was 80mAh·g-1-Si,which meant reversible amount of sodium intercalation.The discharge capacity slightly decreased to 70mAh·g-1-Si after 10 cycles.展开更多
文摘Iron disulfide(FeS_2)cathode active material was prepared from iron and sulfur at room temperature by high energy mechanical alloying.Modified FeS_2 composites containing Co or Ni transition metal powders as additives were also prepared by the same method.Lithium cells with these FeS_2 cathodes were studied for charge-discharge properties at room temperature using 0.5M LiTFSI in tetra(ethylene glycol)dimethyl ether(TEGDME)solvent.Cyclic voltammetry showed two anodic oxidation peaks at 1.8 and 2.5V and two cathodic reduction peaks at 2.0 and 1.3 V for FeS_2 with metal additives.The addition of 5wt% Co and 3wt% Ni resulted in an enhancement of the first discharge capacity giving 571 and 844mAh/g respectively at 0.1C-rate.The cycle performance was also enhanced remarkably by the addition of these electrically conductive transition metals in the active material.FeS_2 with 5wt% Co exhibited a stable cycle performance delivering a reversible capacity of 338mAh/g(37.8% of theoretical capacity)after 20 cycles.
文摘Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide particle.But indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst.In this work,Gallium oxide(β-Ga_2O_3)nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700-1000℃ using the iron,nickel,copper,cobalt and zinc oxide as a catalyst,respectively.The β-Ga_2O_3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850,900 and 950℃ in all the catalysts.But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst.As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods,and its diameter increased.From these results,we could be proposed that the growth mechanism of β-Ga_2O_3 nanowires was changed with synthesis temperature of nanowires.Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM,FE-SEM,EDX and XRD.
文摘In order to investigate the possibility of Si thin film as an anode for Na battery,we studied the electrochemical intercalation of sodium into the Si film.Amorphous Si thin film electrode was prepared using DC magnetron sputtering.Sodium ion could intercalate into Si thin film upto Na0.52Si,i.e.530mAh·g-1-Si.The first discharge capacity was 80mAh·g-1-Si,which meant reversible amount of sodium intercalation.The discharge capacity slightly decreased to 70mAh·g-1-Si after 10 cycles.
