LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemi...LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.展开更多
The synthesis and transport properties of the Li6La3BiSnO1212 solid electrolyte by a solid-state reaction were reported. The condition to synthesize the Li6La3BiSnO1212 is 785 °C for 36 h in air. The refined latt...The synthesis and transport properties of the Li6La3BiSnO1212 solid electrolyte by a solid-state reaction were reported. The condition to synthesize the Li6La3BiSnO1212 is 785 °C for 36 h in air. The refined lattice constant of Li6La3 BiSnO1212 is 13.007A. Qualitative phase analysis by X-ray powder diffraction patterns combined with the Rietveld method reveals garnet type compounds as major phases. The Li-ion conductivity of the prepared Li6La3BiSnO12 is 0.85×10^-4 S/cm at 22 °C, which is comparable with that of the Li5La3Bi2O12. The Li6La3BiSnO1212 compounds are chemically stable against Li CoO2 which is widely used as cathode material up to 700 °C but not against the Li Mn2O4 if the temperature is higher than 550 °C. The Li6La3 BiSnO1212 exhibits higher chemical stability than Li5La3Bi2O12, which is due to Sn substitution for Bi.展开更多
Microwave irradiation was employed to assist the synthesis of poly（amino-quinone） （PAQ） from p-benzoquinone and diamines in solid state. The effects of power, time, and pattern （continuously or intermittently） o...Microwave irradiation was employed to assist the synthesis of poly（amino-quinone） （PAQ） from p-benzoquinone and diamines in solid state. The effects of power, time, and pattern （continuously or intermittently） of microwave irradiation on yield and intrinsic viscosity of PAQs were studied. It is shown that the continuous microwave irradiation at a high power leads to rapid increase of yield and a sudden halt in polymerization afterwards, due to the subsequent loss of volatile reactants at a high reaction temperature. Alternatively, the high-power microwave irradiation is applicable to raising the yield if used intermittently. In contras4 the low-power microwave irradiation favours the way of continuous exposure to ensure sufficient heat for polymerization. In both cases of high and low power, the yield and intrinsic viscosity can be further promoted by prolonging the exposure time. It is found that under a preliminarily optimized condition of intermittent irradiation at 490 W with six sequences of 5 min irradiation followed by 5 rain interval, the yield and intrinsic viscosity of PAQ from p-benzoquinone and p-phenylene diamine can reach as high as 83% and 41.9 mL/g, respectively.展开更多
Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzit...Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.展开更多
基金Project(76600)supported by Postdoctoral Science Foundation of Central South University
文摘LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.
基金Project(51372278)supported by the National Natural Science Foundation of ChinaProject(2010RS4015)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2014ejing004)supported by the Hunan Intellectual Property Bureau,ChinaProject(CSUZC2014020)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘The synthesis and transport properties of the Li6La3BiSnO1212 solid electrolyte by a solid-state reaction were reported. The condition to synthesize the Li6La3BiSnO1212 is 785 °C for 36 h in air. The refined lattice constant of Li6La3 BiSnO1212 is 13.007A. Qualitative phase analysis by X-ray powder diffraction patterns combined with the Rietveld method reveals garnet type compounds as major phases. The Li-ion conductivity of the prepared Li6La3BiSnO12 is 0.85×10^-4 S/cm at 22 °C, which is comparable with that of the Li5La3Bi2O12. The Li6La3BiSnO1212 compounds are chemically stable against Li CoO2 which is widely used as cathode material up to 700 °C but not against the Li Mn2O4 if the temperature is higher than 550 °C. The Li6La3 BiSnO1212 exhibits higher chemical stability than Li5La3Bi2O12, which is due to Sn substitution for Bi.
基金Project(50804055) supported by the National Natural Science Foundation of China
文摘Microwave irradiation was employed to assist the synthesis of poly（amino-quinone） （PAQ） from p-benzoquinone and diamines in solid state. The effects of power, time, and pattern （continuously or intermittently） of microwave irradiation on yield and intrinsic viscosity of PAQs were studied. It is shown that the continuous microwave irradiation at a high power leads to rapid increase of yield and a sudden halt in polymerization afterwards, due to the subsequent loss of volatile reactants at a high reaction temperature. Alternatively, the high-power microwave irradiation is applicable to raising the yield if used intermittently. In contras4 the low-power microwave irradiation favours the way of continuous exposure to ensure sufficient heat for polymerization. In both cases of high and low power, the yield and intrinsic viscosity can be further promoted by prolonging the exposure time. It is found that under a preliminarily optimized condition of intermittent irradiation at 490 W with six sequences of 5 min irradiation followed by 5 rain interval, the yield and intrinsic viscosity of PAQ from p-benzoquinone and p-phenylene diamine can reach as high as 83% and 41.9 mL/g, respectively.
基金Project(2009K06_03) supported by the Scientific and Technological Program of Shaanxi Province,China
文摘Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.
