As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for catho...As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for cathode material LiFePO4/C was introduced in order to improve its electrochemical performance. LiFePO4/C in the three-layer electrode exhibited superior rate capability in comparison with that in the two-layer electrode in accordance with charge-discharge examination. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that Fe3＋/Fe2＋ redox couple for LiFePO4 in the three-layer electrode displayed faster kinetics, better reversibility and much lower charge transfer resistance than that in the two-layer electrode in electrochemical process. For three-layer electrode, the holes in the surface of active material layer were filled by smaller acetylene black grains, which formed electrical connections and provided more pathways to electron transport to/from LiFePO4/C particles exposed to the bulk electrolyte.展开更多
Based on an effective screen-printing process,a novel sandwich layered cathode electrode was developed on a cathode faceplate.The ZnO electrode was sandwiched between an indium tin oxide（ITO） electrode layer and a s...Based on an effective screen-printing process,a novel sandwich layered cathode electrode was developed on a cathode faceplate.The ZnO electrode was sandwiched between an indium tin oxide（ITO） electrode layer and a silver electrode layer,and the carbon nanotube was prepared directly on the exposed ITO electrode layer surface.The cathode potential could be conducted to the carbon nanotube with the sandwich layered cathode electrode.Using the carbon nanotube as a field emitter,a triode field emission display prototype with a sandwich layered cathode electrode was fabricated,which possessed a better field emission characteristic,higher luminous brightness and better emission image luminance uniformity.The turn-on electric field was 1.88 V/μm and the measured maximum field emission current was 2273.6μA at 3.19 V/μm.By the method of adjusting the field emission current,the electron-emitting uniform capacity of the carbon nanotube cold cathode could be modified, and the emission image luminance uniformity and the emission current stability of triode field emission display prototype was also be improved significantly.The emission current fluctuation of the sandwich layered cathode electrode type field emission display was less than 1.1%.Furthermore,the total manufacture cost of the triode field emission display prototype was low.展开更多
The development of a simple,fast,and sensitive method for Se(Ⅳ)determination is detailed in the present work.Experimental conditions were optimized using differential pulse and square wave cathodic stripping voltamme...The development of a simple,fast,and sensitive method for Se(Ⅳ)determination is detailed in the present work.Experimental conditions were optimized using differential pulse and square wave cathodic stripping voltammetry.An ex-situ bismuth film was deposited on the surface of a glassy carbon electrode and used as the working electrode.An exhaustive study of potential interferents was performed.Cu(Ⅱ)interference is one of the most significant challenges in Se(Ⅳ)determination.By integrating acetonitrile in the supporting electrolyte,Cu(Ⅰ)was stabilized through complex formation,thereby preventing metallic copper deposition and copper selenide formation.Even with a 50-fold excess of Cu(Ⅱ),no interference was observed in the quantification of Se(Ⅳ).The proposed method was validated using two certifi ed reference materials(CRMs)and applied to the analysis of four water samples,three of which were spiked with Se(Ⅳ).Satisfactory results were obtained from the validation and water sample analysis.展开更多
The redox behavior of spironolactone（SP） drug in Britton-Robinson（BR） buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry（DPCSV） and cyclic voltammetry（CV） at hanging mercur...The redox behavior of spironolactone（SP） drug in Britton-Robinson（BR） buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry（DPCSV） and cyclic voltammetry（CV） at hanging mercury dropping electrode（HMDE）.At pH 9-10.5,the DPCSV of SP drug showed two cathodic peaks at1.15 and1.38 V at the HMDE vs.Ag/AgCl reference electrode.In the CV,at pH 9-10,the dependence of the cathodic peak current,Ip,c and peak potential,Ep,c of the second peak（Ep,c2） on the scan rate（n） and on the depolizer（SP） concentrations was typical of an electrode coupled（EC） chemical reaction type mechanism.The plot of Ip,cat 1.380 V of the DPCSV vs.SP concentration at pH 9 was linear over the concentration range of 1.2×1010-9.6×107 M.The lower limit of detection（LLOD） and limit of quantification（LOQ） of the drug were 1.1×1011 and 4.14×1011 M,respectively.The method was successfully applied for the analysis of SP residues in industrial wastewater,in pure form（98.273.1%） and in drug formulations e.g.Aldactones tablet（98.3572.9%）.The method was validated by comparison with HPLC and the official data methods.展开更多
Composites of Na_(0.44)Mn O_2, Na_(0.7)Mn O_(2.05), and Na_(0.91) Mn O_2 were synthesized by facile solid-state reaction, ball milling, and annealing methods. Two different composites of identical overall composition ...Composites of Na_(0.44)Mn O_2, Na_(0.7)Mn O_(2.05), and Na_(0.91) Mn O_2 were synthesized by facile solid-state reaction, ball milling, and annealing methods. Two different composites of identical overall composition but drastically different morphologies and microstructures were synthesized. A composite of a hierarchical porous microstructure with primary and secondary particles(i.e., a "meatball-like" microstructure) achieved an excellent stable capacity of 126 m A h g^(-1) after 100 cycles. The rate capability of the composite could be dramatically enhanced by another round of high-energy ball milling and reannealing; subsequently, a composite that was made up of irregular rods was obtained, for which the capacity was improved by more than 230% to achieve ~53 m A h g^(-1) at a particularly high discharge rate of 50 C. This study demonstrated the feasibility of tailoring the electrochemical performance of electrode materials by simply changing their microstructures via facile ball milling and heat treatments, which can be particularly useful for optimizing composite electrodes for sodium-ion batteries.展开更多
基金Project(2010ZCO51)supported by Natural Science Foundation of Yunnan ProvinceProject supported by Analysis and Testing Foundation(2009-041)Starting Research Fund(14118245)from Kunming University of Science and Technology
文摘As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for cathode material LiFePO4/C was introduced in order to improve its electrochemical performance. LiFePO4/C in the three-layer electrode exhibited superior rate capability in comparison with that in the two-layer electrode in accordance with charge-discharge examination. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that Fe3＋/Fe2＋ redox couple for LiFePO4 in the three-layer electrode displayed faster kinetics, better reversibility and much lower charge transfer resistance than that in the two-layer electrode in electrochemical process. For three-layer electrode, the holes in the surface of active material layer were filled by smaller acetylene black grains, which formed electrical connections and provided more pathways to electron transport to/from LiFePO4/C particles exposed to the bulk electrolyte.
基金Project supported by the National Natural Science Foundation of China(Nos.51072184,60976058)the Natural Science Research Project of Henan Provincial Education Department(No.2009B510019)
文摘Based on an effective screen-printing process,a novel sandwich layered cathode electrode was developed on a cathode faceplate.The ZnO electrode was sandwiched between an indium tin oxide（ITO） electrode layer and a silver electrode layer,and the carbon nanotube was prepared directly on the exposed ITO electrode layer surface.The cathode potential could be conducted to the carbon nanotube with the sandwich layered cathode electrode.Using the carbon nanotube as a field emitter,a triode field emission display prototype with a sandwich layered cathode electrode was fabricated,which possessed a better field emission characteristic,higher luminous brightness and better emission image luminance uniformity.The turn-on electric field was 1.88 V/μm and the measured maximum field emission current was 2273.6μA at 3.19 V/μm.By the method of adjusting the field emission current,the electron-emitting uniform capacity of the carbon nanotube cold cathode could be modified, and the emission image luminance uniformity and the emission current stability of triode field emission display prototype was also be improved significantly.The emission current fluctuation of the sandwich layered cathode electrode type field emission display was less than 1.1%.Furthermore,the total manufacture cost of the triode field emission display prototype was low.
基金support from ANID by Proyecto PAI N°77190012Proyecto FONDEQUIP EQM150101。
文摘The development of a simple,fast,and sensitive method for Se(Ⅳ)determination is detailed in the present work.Experimental conditions were optimized using differential pulse and square wave cathodic stripping voltammetry.An ex-situ bismuth film was deposited on the surface of a glassy carbon electrode and used as the working electrode.An exhaustive study of potential interferents was performed.Cu(Ⅱ)interference is one of the most significant challenges in Se(Ⅳ)determination.By integrating acetonitrile in the supporting electrolyte,Cu(Ⅰ)was stabilized through complex formation,thereby preventing metallic copper deposition and copper selenide formation.Even with a 50-fold excess of Cu(Ⅱ),no interference was observed in the quantification of Se(Ⅳ).The proposed method was validated using two certifi ed reference materials(CRMs)and applied to the analysis of four water samples,three of which were spiked with Se(Ⅳ).Satisfactory results were obtained from the validation and water sample analysis.
基金funded by the Deanship of Scientific Research (DSR),King Abdulaziz University under grant number 172/428
文摘The redox behavior of spironolactone（SP） drug in Britton-Robinson（BR） buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry（DPCSV） and cyclic voltammetry（CV） at hanging mercury dropping electrode（HMDE）.At pH 9-10.5,the DPCSV of SP drug showed two cathodic peaks at1.15 and1.38 V at the HMDE vs.Ag/AgCl reference electrode.In the CV,at pH 9-10,the dependence of the cathodic peak current,Ip,c and peak potential,Ep,c of the second peak（Ep,c2） on the scan rate（n） and on the depolizer（SP） concentrations was typical of an electrode coupled（EC） chemical reaction type mechanism.The plot of Ip,cat 1.380 V of the DPCSV vs.SP concentration at pH 9 was linear over the concentration range of 1.2×1010-9.6×107 M.The lower limit of detection（LLOD） and limit of quantification（LOQ） of the drug were 1.1×1011 and 4.14×1011 M,respectively.The method was successfully applied for the analysis of SP residues in industrial wastewater,in pure form（98.273.1%） and in drug formulations e.g.Aldactones tablet（98.3572.9%）.The method was validated by comparison with HPLC and the official data methods.
基金supported by the U.S.NSF(Grant No.DMR-1320615)subsequently an NSSEFF fellowship(Grant No.N00014-15-1-0030)
文摘Composites of Na_(0.44)Mn O_2, Na_(0.7)Mn O_(2.05), and Na_(0.91) Mn O_2 were synthesized by facile solid-state reaction, ball milling, and annealing methods. Two different composites of identical overall composition but drastically different morphologies and microstructures were synthesized. A composite of a hierarchical porous microstructure with primary and secondary particles(i.e., a "meatball-like" microstructure) achieved an excellent stable capacity of 126 m A h g^(-1) after 100 cycles. The rate capability of the composite could be dramatically enhanced by another round of high-energy ball milling and reannealing; subsequently, a composite that was made up of irregular rods was obtained, for which the capacity was improved by more than 230% to achieve ~53 m A h g^(-1) at a particularly high discharge rate of 50 C. This study demonstrated the feasibility of tailoring the electrochemical performance of electrode materials by simply changing their microstructures via facile ball milling and heat treatments, which can be particularly useful for optimizing composite electrodes for sodium-ion batteries.
