In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show t...In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show that templates and calcination time have significant impacts on the purity,particle size and morphology of LiFePO_4 particles.The as-prepared LiFePO_4 particles using polyvinyl pyrrolidone(PVP) template with additional one hour calcination at 700℃exhibit characteristics of good crystallinity,uniform size distribution,high capacity and cycling performance.The specific discharge capacities of 141.2 and 114.0mA·h/g were obtained at the charge/discharge rates of 0.1 and 1.0 C,respectively.It retained 96.0%of an initial capacity after 100 cycles at 1.0 C rate.The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.展开更多
A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition w...A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition was optimized for obtaining uniformly distributed sub-micrometer sized Au array on the electrode surface. The hy-drogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue (MB) molecules on the surface of sm-Au and covering a cross-linked horseradish peroxidase (HRP) layer, labeled as HRP/MB/sm-Au/GCE. The characteristics of this biosensor were evaluated with respect to applied potential and pH. The amperometric re-sponse of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10-61.11×10-2 mol/L. A detection limit (s/n=3) of 3.0×10-6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to -400 mV vs. SCE. The immobilized MB molecules shuttled electrons at a=0.77 and an apparent electron transfer rate constant of 0'sk=0.053 s-1. Interference of ascorbic acid, dopamine and uric acid was investigated. This sensor has very good stability and reproducibility for long-term use.展开更多
The properties of yttria stabilized zirconia（YSZ） related to the sintering process were discussed.YSZ nano-powders about 40-100 nm as raw material,the sub-micrometer grain sizes such as 0.4-3 μm in YSZ were gotten ...The properties of yttria stabilized zirconia（YSZ） related to the sintering process were discussed.YSZ nano-powders about 40-100 nm as raw material,the sub-micrometer grain sizes such as 0.4-3 μm in YSZ were gotten by sintering process at 1300 ℃,which was performed at 1000 ℃ for 2 h,then raised the temperature at the rate of 50 ℃ / h to 1400 ℃,then decreased directly to 1300 ℃ in 30 minutes,finally at 1300 ℃ for 5-20 hours.The ratio of bigger grain size becomes larger as the holding time increasing at 1300 ℃.The grains less than 1 μm are about 50%,eg,43.2%,52.2% and 51.1% related to 1300 ℃ holding 5 hours,8 hours and 10 hours,respectively.As YSZ grain size became small,the electrical conductivities did not decrease,even increased,about 0.20 s/cm at 1000 ℃.The reduced sintering temperature and time were benefited to co-fire with the electrodes in electrode-supported SOFCs.展开更多
基金the Fundamental Research Funds for the Central Universities of China(No.DUT11NY08)
文摘In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show that templates and calcination time have significant impacts on the purity,particle size and morphology of LiFePO_4 particles.The as-prepared LiFePO_4 particles using polyvinyl pyrrolidone(PVP) template with additional one hour calcination at 700℃exhibit characteristics of good crystallinity,uniform size distribution,high capacity and cycling performance.The specific discharge capacities of 141.2 and 114.0mA·h/g were obtained at the charge/discharge rates of 0.1 and 1.0 C,respectively.It retained 96.0%of an initial capacity after 100 cycles at 1.0 C rate.The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.
文摘A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition was optimized for obtaining uniformly distributed sub-micrometer sized Au array on the electrode surface. The hy-drogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue (MB) molecules on the surface of sm-Au and covering a cross-linked horseradish peroxidase (HRP) layer, labeled as HRP/MB/sm-Au/GCE. The characteristics of this biosensor were evaluated with respect to applied potential and pH. The amperometric re-sponse of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10-61.11×10-2 mol/L. A detection limit (s/n=3) of 3.0×10-6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to -400 mV vs. SCE. The immobilized MB molecules shuttled electrons at a=0.77 and an apparent electron transfer rate constant of 0'sk=0.053 s-1. Interference of ascorbic acid, dopamine and uric acid was investigated. This sensor has very good stability and reproducibility for long-term use.
基金Funded by the National Natural Science Foundation of China (NSFC)(No. 50730004)the New Century Elitist Project (No. NCET-06-0203)
文摘The properties of yttria stabilized zirconia（YSZ） related to the sintering process were discussed.YSZ nano-powders about 40-100 nm as raw material,the sub-micrometer grain sizes such as 0.4-3 μm in YSZ were gotten by sintering process at 1300 ℃,which was performed at 1000 ℃ for 2 h,then raised the temperature at the rate of 50 ℃ / h to 1400 ℃,then decreased directly to 1300 ℃ in 30 minutes,finally at 1300 ℃ for 5-20 hours.The ratio of bigger grain size becomes larger as the holding time increasing at 1300 ℃.The grains less than 1 μm are about 50%,eg,43.2%,52.2% and 51.1% related to 1300 ℃ holding 5 hours,8 hours and 10 hours,respectively.As YSZ grain size became small,the electrical conductivities did not decrease,even increased,about 0.20 s/cm at 1000 ℃.The reduced sintering temperature and time were benefited to co-fire with the electrodes in electrode-supported SOFCs.
