The electro-deoxidation of V2O3 precursors was studied. Experiments were carried out with a two-terminal electrochemical cell, which was comprised of a molten electrolyte of CaCl2 and NaC1 with additions of CaO, a cat...The electro-deoxidation of V2O3 precursors was studied. Experiments were carried out with a two-terminal electrochemical cell, which was comprised of a molten electrolyte of CaCl2 and NaC1 with additions of CaO, a cathode of compact V2O3, and a graphite anode under the potential of 3.0 V at 1173 K. The phase constitution and composition as well as the morphology of the samples were studied by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. 3 g of V2O3 could be converted to vanadium metal powder within the processing time of 8 h. The kinetic pathway was investigated by analyzing the product phase in samples prepared at different reduction stages. CaO added in the reduction path of V2O3 formed the intermediate product CaV2O4.展开更多
High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety is...High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety issues and low energy density.Here we hypothesize that a cobalt vanadate oxide,Co_(2)VO_(4),can be attractive anode material for fast-charging LIBs due to its high capacity(~1000 mAh g^(−1))and safe lithiation potential(~0.65 V vs.Li^(+)/Li).The Li+diffusion coefficient of Co2VO4 is evaluated by theoretical calculation to be as high as 3.15×10^(-10) cm^(2) s^(−1),proving Co_(2)VO_(4) a promising anode in fast-charging LIBs.A hexagonal porous Co2VO4 nanodisk(PCVO ND)structure is designed accordingly,featuring a high specific surface area of 74.57 m^(2) g^(−1) and numerous pores with a pore size of 14 nm.This unique structure succeeds in enhancing Li^(+) and electron transfer,leading to superior fast-charging performance than current commercial anodes.As a result,the PCVO ND shows a high initial reversible capacity of 911.0 mAh g^(−1) at 0.4 C,excellent fast-charging capacity(344.3 mAh g^(−1) at 10 C for 1000 cycles),outstanding long-term cycling stability(only 0.024% capacity loss per cycle at 10 C for 1000 cycles),confirming the commercial feasibility of PCVO ND in fast-charging LIBs.展开更多
A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi ...A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51154002 and 50834001)Panzhihua New Steel and Vanadium Co.Ltd
文摘The electro-deoxidation of V2O3 precursors was studied. Experiments were carried out with a two-terminal electrochemical cell, which was comprised of a molten electrolyte of CaCl2 and NaC1 with additions of CaO, a cathode of compact V2O3, and a graphite anode under the potential of 3.0 V at 1173 K. The phase constitution and composition as well as the morphology of the samples were studied by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. 3 g of V2O3 could be converted to vanadium metal powder within the processing time of 8 h. The kinetic pathway was investigated by analyzing the product phase in samples prepared at different reduction stages. CaO added in the reduction path of V2O3 formed the intermediate product CaV2O4.
基金supported by the National Key Research and Development Project(2018YFE0124800)the National Nature Science Foundation of China(51702157,51873086,51673096).
文摘High-energy–density lithium-ion batteries(LIBs)that can be safely fast-charged are desirable for electric vehicles.However,sub-optimal lithiation potential and low capacity of commonly used LIBs anode cause safety issues and low energy density.Here we hypothesize that a cobalt vanadate oxide,Co_(2)VO_(4),can be attractive anode material for fast-charging LIBs due to its high capacity(~1000 mAh g^(−1))and safe lithiation potential(~0.65 V vs.Li^(+)/Li).The Li+diffusion coefficient of Co2VO4 is evaluated by theoretical calculation to be as high as 3.15×10^(-10) cm^(2) s^(−1),proving Co_(2)VO_(4) a promising anode in fast-charging LIBs.A hexagonal porous Co2VO4 nanodisk(PCVO ND)structure is designed accordingly,featuring a high specific surface area of 74.57 m^(2) g^(−1) and numerous pores with a pore size of 14 nm.This unique structure succeeds in enhancing Li^(+) and electron transfer,leading to superior fast-charging performance than current commercial anodes.As a result,the PCVO ND shows a high initial reversible capacity of 911.0 mAh g^(−1) at 0.4 C,excellent fast-charging capacity(344.3 mAh g^(−1) at 10 C for 1000 cycles),outstanding long-term cycling stability(only 0.024% capacity loss per cycle at 10 C for 1000 cycles),confirming the commercial feasibility of PCVO ND in fast-charging LIBs.
基金Supported by the National Natural Science Foundation of China(21676023,21376025)
文摘A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.
