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2015 Volume 32 Issue 11
2015, 32(11): 1221-1230
doi: 10.11944/j.issn.1000-0518.2015.11.150113
Abstract:
Ti-V-based hydrogen storage alloys perform well at ambient conditions and show better hydrogen storage capacity than conventional alloys. Thus,it is early utilized in purification and recovery of hydrogen,transport and storage of hydrogen and heat pump. Besides,it is also widely researched and concerned in gas mixture separation,disposure of hydrogen isotope in nuclear reactor,anode material of Ni-H and fuel cell battery. Based on the current research and development situation of Ti-V based alloys,the privileges,main constraints with the cause included and the methods of modification were briefly summarized. Moreover,to further understand the hydrogen storage mechanism of Ti-V based alloys and to build the relationship between alloy constituents and hydrogen storage properties,this review will focus on the phases and structures of Ti-V based alloys and its hydrides,optimization design of constituents and composition,as well as the development direction of it.
Ti-V-based hydrogen storage alloys perform well at ambient conditions and show better hydrogen storage capacity than conventional alloys. Thus,it is early utilized in purification and recovery of hydrogen,transport and storage of hydrogen and heat pump. Besides,it is also widely researched and concerned in gas mixture separation,disposure of hydrogen isotope in nuclear reactor,anode material of Ni-H and fuel cell battery. Based on the current research and development situation of Ti-V based alloys,the privileges,main constraints with the cause included and the methods of modification were briefly summarized. Moreover,to further understand the hydrogen storage mechanism of Ti-V based alloys and to build the relationship between alloy constituents and hydrogen storage properties,this review will focus on the phases and structures of Ti-V based alloys and its hydrides,optimization design of constituents and composition,as well as the development direction of it.
2015, 32(11): 1231-1239
doi: 10.11944/j.issn.1000-0518.2015.11.150070
Abstract:
Sixteen new β-amino ketones containing sulfadiazine moiety have been directly synthesized through atom-economic Mannich reaction of sulfadiazine with 1-acetonaphthone and some aromatic aldehydes. The chemical structures of these obtained compounds were identified by 1H NMR, 13C NMR,and HRMS. The biological assay results show that all obtained compounds in the concentration range of 17.04~19.69 nmol/L possess very weak α-glucosidase inhibitory activities, while some compounds can activate peroxisome proliferator-activated receptor response element(PPRE) moderately,of which one exhibits the strongest activity(52%).
Sixteen new β-amino ketones containing sulfadiazine moiety have been directly synthesized through atom-economic Mannich reaction of sulfadiazine with 1-acetonaphthone and some aromatic aldehydes. The chemical structures of these obtained compounds were identified by 1H NMR, 13C NMR,and HRMS. The biological assay results show that all obtained compounds in the concentration range of 17.04~19.69 nmol/L possess very weak α-glucosidase inhibitory activities, while some compounds can activate peroxisome proliferator-activated receptor response element(PPRE) moderately,of which one exhibits the strongest activity(52%).
2015, 32(11): 1240-1245
doi: 10.11944/j.issn.1000-0518.2015.11.150081
Abstract:
Tedizolid with a yield of 82.9% was synthesized by the Suzuki coupling reaction of 5-bromo-2-(2-methyl-2H-tetrazol-5-yl) pyridine and(5R)-3-(4-bromo-3-fluorophenyl)-5-(hydroxymethyl)-2-oxazolidinone which was prepared from bis(pinacolato) diboron using 1,1'-bis(diphenylphosphino) ferrocene-palladium(Ⅱ) dichloride dichloromethane complex as the catalyst. The effect of the catalytic system on the reaction of the borylation reaction and Suzuki reaction was investigated respectively,and the optimum reaction conditions were determined. Tedizolid phosphate was obtained by reaction of tedizolid with dibenzyl N,N-diisopropylphosphoramidite,and subsequent debenzylation with Pd/C. The total yield is 66.2%.
Tedizolid with a yield of 82.9% was synthesized by the Suzuki coupling reaction of 5-bromo-2-(2-methyl-2H-tetrazol-5-yl) pyridine and(5R)-3-(4-bromo-3-fluorophenyl)-5-(hydroxymethyl)-2-oxazolidinone which was prepared from bis(pinacolato) diboron using 1,1'-bis(diphenylphosphino) ferrocene-palladium(Ⅱ) dichloride dichloromethane complex as the catalyst. The effect of the catalytic system on the reaction of the borylation reaction and Suzuki reaction was investigated respectively,and the optimum reaction conditions were determined. Tedizolid phosphate was obtained by reaction of tedizolid with dibenzyl N,N-diisopropylphosphoramidite,and subsequent debenzylation with Pd/C. The total yield is 66.2%.
2015, 32(11): 1246-1252
doi: 10.11944/j.issn.1000-0518.2015.11.150108
Abstract:
A metal-free cyclization reaction of activated alkenes with nonafluorobutyl iodide toward perfluorinated oxindoles was developed. In the presence of azodiisobutyronitrile(AIBN), various N-arylacrylamide underwent radical cyclization smoothly to afford a series of synthetically important perfluorinated oxindoles in 53%~85% yields. This work provides a novel high efficient,cheap and green route for the synthesis of perfluorinated oxindoles having potential medicinal values.
A metal-free cyclization reaction of activated alkenes with nonafluorobutyl iodide toward perfluorinated oxindoles was developed. In the presence of azodiisobutyronitrile(AIBN), various N-arylacrylamide underwent radical cyclization smoothly to afford a series of synthetically important perfluorinated oxindoles in 53%~85% yields. This work provides a novel high efficient,cheap and green route for the synthesis of perfluorinated oxindoles having potential medicinal values.
2015, 32(11): 1253-1258
doi: 10.11944/j.issn.1000-0518.2015.11.150124
Abstract:
A new Cu(OAc)2-catalyzed oxidative coupling of disulfides with tetrahydrofuran for the synthesis of etherified sulfides has been developed. In the presence of Cu(OAc)2(10% molar fraction) and H2O2(35%,2 equiv),a variety of disulfides(0.5 mmol) were treated with tetrahydrofuran(2 mL) at 120℃ to afford the corresponding etherified sulfides in moderate to high yields. This method employs 35% aqueous H2O2 as the green oxidant,and provides an efficient way for the formation of the C-S bonds.
A new Cu(OAc)2-catalyzed oxidative coupling of disulfides with tetrahydrofuran for the synthesis of etherified sulfides has been developed. In the presence of Cu(OAc)2(10% molar fraction) and H2O2(35%,2 equiv),a variety of disulfides(0.5 mmol) were treated with tetrahydrofuran(2 mL) at 120℃ to afford the corresponding etherified sulfides in moderate to high yields. This method employs 35% aqueous H2O2 as the green oxidant,and provides an efficient way for the formation of the C-S bonds.
2015, 32(11): 1259-1267
doi: 10.11944/j.issn.1000-0518.2015.11.150144
Abstract:
2-Phenyl-1,2,3-triazoledehyde and quinoxalin-2-carboxaldehyde immobilized on mesoporous MCM-41 by imine bond respectively. Six multinitrogen heterocyclic Schiff bases(L1~L6) modified MCM-41 were synthesized. These catalysts were characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),thermogravimetric analysis(TG) and scanning electron microscopy(SEM). Na VO3 and Schiff Base complex immobilized on MCM-41 was used for catalytic oxidation of benzene to phenol. The yield of phenol was determined by gas chromatography. Reaction conditions,such as ligand,metal salt,temperature,solvent,the catalyst amount,reaction time and oxidants were systematically investigated. Under optimized conditions,the yield of phenol is up to 23.9%(more than 90% selectivity). Scaled-up(5 times) reaction test using the current catalyst system gives a good yield(23%) and selectivity(up to 90%),while catalyst shows no significant decrease of catalytic activity after 3 times recycles.
2-Phenyl-1,2,3-triazoledehyde and quinoxalin-2-carboxaldehyde immobilized on mesoporous MCM-41 by imine bond respectively. Six multinitrogen heterocyclic Schiff bases(L1~L6) modified MCM-41 were synthesized. These catalysts were characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),thermogravimetric analysis(TG) and scanning electron microscopy(SEM). Na VO3 and Schiff Base complex immobilized on MCM-41 was used for catalytic oxidation of benzene to phenol. The yield of phenol was determined by gas chromatography. Reaction conditions,such as ligand,metal salt,temperature,solvent,the catalyst amount,reaction time and oxidants were systematically investigated. Under optimized conditions,the yield of phenol is up to 23.9%(more than 90% selectivity). Scaled-up(5 times) reaction test using the current catalyst system gives a good yield(23%) and selectivity(up to 90%),while catalyst shows no significant decrease of catalytic activity after 3 times recycles.
2015, 32(11): 1268-1274
doi: 10.11944/j.issn.1000-0518.2015.11.150117
Abstract:
Different proportions of PCL/PLLA random copolymers made from ε-caprolactone(ε-CL) and L-lactide(L-LA) were synthesized by ring-opening polymerization. Copolymers were added to PLA by melt blending to afford PLA/P(CL/LLA) blends. The compatibility,thermal and mechanical properties of the blends were studied. The results show that the compatibility of PLA and P(CL/LLA) is closely related to the average length of the lactide unit in copolymer. When the number-average length of lactide in P(CL/LLA) is longer than 3.4,the copolymer can interact with PLA very well. Caprolactone sequences can provide flexible units for the copolymer,and improve the toughness for the blends. The elongation at break of the blends can reach as high as 500%.
Different proportions of PCL/PLLA random copolymers made from ε-caprolactone(ε-CL) and L-lactide(L-LA) were synthesized by ring-opening polymerization. Copolymers were added to PLA by melt blending to afford PLA/P(CL/LLA) blends. The compatibility,thermal and mechanical properties of the blends were studied. The results show that the compatibility of PLA and P(CL/LLA) is closely related to the average length of the lactide unit in copolymer. When the number-average length of lactide in P(CL/LLA) is longer than 3.4,the copolymer can interact with PLA very well. Caprolactone sequences can provide flexible units for the copolymer,and improve the toughness for the blends. The elongation at break of the blends can reach as high as 500%.
2015, 32(11): 1275-1282
doi: 10.11944/j.issn.1000-0518.2015.11.150103
Abstract:
In-situ IR has been applied to study the curing reaction process of dicyandiamide(DICY) with epoxy resin. The combination of FTIR and its generalized two-dimensional infrared correlation spectroscopy(2D-IR) to analyze the curing reaction process can effectively enhance the spectral resolution and reveal the details about the reaction mechanism. Four reactions were detected in the resin network:(i) reversible decomposition of DICY and cyanamide;(ii) copolymerization of cyanamide and epoxy resin to form the intermediate product;(iii) copolymerization of cyanamide and the intermediate product to form imines;(iv) rearrangement of the imine structure to form the amide structure. It is very effective to explain the curing mechanism of thermosetting resin by using in-situ IR,FTIR and 2D-IR.
In-situ IR has been applied to study the curing reaction process of dicyandiamide(DICY) with epoxy resin. The combination of FTIR and its generalized two-dimensional infrared correlation spectroscopy(2D-IR) to analyze the curing reaction process can effectively enhance the spectral resolution and reveal the details about the reaction mechanism. Four reactions were detected in the resin network:(i) reversible decomposition of DICY and cyanamide;(ii) copolymerization of cyanamide and epoxy resin to form the intermediate product;(iii) copolymerization of cyanamide and the intermediate product to form imines;(iv) rearrangement of the imine structure to form the amide structure. It is very effective to explain the curing mechanism of thermosetting resin by using in-situ IR,FTIR and 2D-IR.
2015, 32(11): 1283-1289
doi: 10.11944/j.issn.1000-0518.2015.11.150137
Abstract:
A novel molecularly imprinted polymer(DMIP) for trans-resveratrol was fabricated with bonded β-cyclodextrin(β-CD) and methacrylic acid as double monomers. Molecularly imprinted solid phase extraction column prepared with bonded double monomers has higher imprinting effect to the template molecule. DMIP prepared using bonded β-CD and methacylic acid, either separately or combined have shown various recognition properties. The results of adsorption experiments indicated that the selectivity of DMIP is superior to those obtained with only methacrylic acid(SMIP). Molecularly imprinted solid phase extraction column was used to determine the trans-resveratrol in wine and Chinese liquor samples. The recoveries of 87.9%~93.2%,87.9%~93.2% and 89.3%~91.2% are obtained for red wine and white wine and Chinese Liquor,respectively. This method is highly sensitive and specific for the analyte,along with a low limit of determination at 0.001 mg/L and a linear range from 0.003 to 2 mg/L.
A novel molecularly imprinted polymer(DMIP) for trans-resveratrol was fabricated with bonded β-cyclodextrin(β-CD) and methacrylic acid as double monomers. Molecularly imprinted solid phase extraction column prepared with bonded double monomers has higher imprinting effect to the template molecule. DMIP prepared using bonded β-CD and methacylic acid, either separately or combined have shown various recognition properties. The results of adsorption experiments indicated that the selectivity of DMIP is superior to those obtained with only methacrylic acid(SMIP). Molecularly imprinted solid phase extraction column was used to determine the trans-resveratrol in wine and Chinese liquor samples. The recoveries of 87.9%~93.2%,87.9%~93.2% and 89.3%~91.2% are obtained for red wine and white wine and Chinese Liquor,respectively. This method is highly sensitive and specific for the analyte,along with a low limit of determination at 0.001 mg/L and a linear range from 0.003 to 2 mg/L.
2015, 32(11): 1290-1298
doi: 10.11944/j.issn.1000-0518.2015.11.150145
Abstract:
A bi-templates molecular imprinted polymers(MIPs) was prepared by using quercetin(QT) and rutin(RT) as co-templates. The preparation conditions were optimized. The effects of the molar ratio of two templates and the volume dosage of functional monomer and crosslinker on the adsorption property of MIPs were also studied. Structural characterization of the MIPs was performed by FTIR and SEM. The adsorption dynamics,adsorption isotherm,surface sites distribution and binding selectivity of the MIPs were explored. In addition,the applicability for the MIPs to separate target compound by MIPs solid phase extraction was studied. When the molar ratio of quercetin to rutin is 3:2 and the molar ratio of total templates to functional monomer to cross-linker is 1:8:10,the MIPs obtained possess the highest adsorption capacity toward two templates(47.86 mg/g for quercetin and 60.97 mg/g for rutin). The equilibrium of static adsorption is reached within 3.5 h implying a rapid adsorption dynamics. Scatchard analysis shows that there are four types of binding sites in the polymer matrix,i.e.,two types of high affinity binding sites toward two templates and two types of non-selective recognition sites. The relative distribution coefficient(k=Kd(RT)/Kd(QT),Kd=qe/ρe,Kd-distribution coefficient,qe-equilibrium adsorption amount,ρe-equilibrium mass concentration) much higher than 1.0 reveals a high selectivity for the MIPs toward rutin. The highest relative distribution coefficient(6.669) and separation factor(α=qe(RT)/qe(QT))(25.02) are obtained when the concentration of rutin and quercetin in the model mixture is 0.07 and 0.03 mmol/L,respectively. When using acetonitrile,methanol and methanol-acetic acid mixture as effluents in sequence in the MIPs solid phase extraction of crude extract of sophora flower bud,quercetin and rution can be separately extracted with 96.70% and 94.67% recoveries,respectively.
A bi-templates molecular imprinted polymers(MIPs) was prepared by using quercetin(QT) and rutin(RT) as co-templates. The preparation conditions were optimized. The effects of the molar ratio of two templates and the volume dosage of functional monomer and crosslinker on the adsorption property of MIPs were also studied. Structural characterization of the MIPs was performed by FTIR and SEM. The adsorption dynamics,adsorption isotherm,surface sites distribution and binding selectivity of the MIPs were explored. In addition,the applicability for the MIPs to separate target compound by MIPs solid phase extraction was studied. When the molar ratio of quercetin to rutin is 3:2 and the molar ratio of total templates to functional monomer to cross-linker is 1:8:10,the MIPs obtained possess the highest adsorption capacity toward two templates(47.86 mg/g for quercetin and 60.97 mg/g for rutin). The equilibrium of static adsorption is reached within 3.5 h implying a rapid adsorption dynamics. Scatchard analysis shows that there are four types of binding sites in the polymer matrix,i.e.,two types of high affinity binding sites toward two templates and two types of non-selective recognition sites. The relative distribution coefficient(k=Kd(RT)/Kd(QT),Kd=qe/ρe,Kd-distribution coefficient,qe-equilibrium adsorption amount,ρe-equilibrium mass concentration) much higher than 1.0 reveals a high selectivity for the MIPs toward rutin. The highest relative distribution coefficient(6.669) and separation factor(α=qe(RT)/qe(QT))(25.02) are obtained when the concentration of rutin and quercetin in the model mixture is 0.07 and 0.03 mmol/L,respectively. When using acetonitrile,methanol and methanol-acetic acid mixture as effluents in sequence in the MIPs solid phase extraction of crude extract of sophora flower bud,quercetin and rution can be separately extracted with 96.70% and 94.67% recoveries,respectively.
2015, 32(11): 1299-1306
doi: 10.11944/j.issn.1000-0518.2015.11.150154
Abstract:
A novel magnetic ion imprinted polymers(MWNTs/MIIPs) based on aniline functionalized multiwalled carbon nanotubes was synthesized using Cd2+ as the template,methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The MWNTs/MIIPs were characterized by scanning electron microscopy and infrared spectroscopy in detail. Adsorption studies indicate that the MWNTs/MIIPs show excellent adsorption and selective recognition ability towards Cd2+ with a maximum adsorption capacity of 16.96 mg/g. And the selectivity factor of the MWNTs/MIIPs toward Cd2+/Cu2+,Cd2+/Ni2+,Cd2+/Pb2+ and Cd2+/Cr3+ is 2.03,2.35,2.16 and 2.13,respectively. Combined with atomic absorption spectral analysis technology,the MWNTs/MIIPs were applied for the rapid separation and enrichment of trace Cd2+ in rice.
A novel magnetic ion imprinted polymers(MWNTs/MIIPs) based on aniline functionalized multiwalled carbon nanotubes was synthesized using Cd2+ as the template,methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The MWNTs/MIIPs were characterized by scanning electron microscopy and infrared spectroscopy in detail. Adsorption studies indicate that the MWNTs/MIIPs show excellent adsorption and selective recognition ability towards Cd2+ with a maximum adsorption capacity of 16.96 mg/g. And the selectivity factor of the MWNTs/MIIPs toward Cd2+/Cu2+,Cd2+/Ni2+,Cd2+/Pb2+ and Cd2+/Cr3+ is 2.03,2.35,2.16 and 2.13,respectively. Combined with atomic absorption spectral analysis technology,the MWNTs/MIIPs were applied for the rapid separation and enrichment of trace Cd2+ in rice.
2015, 32(11): 1307-1311
doi: 10.11944/j.issn.1000-0518.2015.11.150026
Abstract:
An amino-functionalized metal ion-imprinted adsorbent was newly synthesized for the selective extraction and removal of Cu(Ⅱ) from aqueous solution. The adsorption capacity of the amino-functionalized ion-imprinted adsorbent was found to be significantly more than that of several adsorbents reported in the literatures. In this work, tetraethylene pentamine(TEPA), tungsten ions as template and glucose are combined together with a specific mole ratio(1:1:5) to prepare carbon-based adsorbents by hydrothermal synthesis. The carbon based adsorbent was characterized by SEM,TEM and XPS. The optimum pH for Cu(Ⅱ) adsorption was found to be 5. The adsorption efficiency of the imprinted material for Cu(Ⅱ) was up to 97.2%,while the efficiencies were 20.1%,9.63%,20.3%,13.3% for Cd2+,Co2+,Ni2+,Zn2+,respectively. The high selectivity indicates that this modified carbon microspheres by the W ion-imprinted method can be used as the selective adsorbent for the removal of copper ions from wastewater.
An amino-functionalized metal ion-imprinted adsorbent was newly synthesized for the selective extraction and removal of Cu(Ⅱ) from aqueous solution. The adsorption capacity of the amino-functionalized ion-imprinted adsorbent was found to be significantly more than that of several adsorbents reported in the literatures. In this work, tetraethylene pentamine(TEPA), tungsten ions as template and glucose are combined together with a specific mole ratio(1:1:5) to prepare carbon-based adsorbents by hydrothermal synthesis. The carbon based adsorbent was characterized by SEM,TEM and XPS. The optimum pH for Cu(Ⅱ) adsorption was found to be 5. The adsorption efficiency of the imprinted material for Cu(Ⅱ) was up to 97.2%,while the efficiencies were 20.1%,9.63%,20.3%,13.3% for Cd2+,Co2+,Ni2+,Zn2+,respectively. The high selectivity indicates that this modified carbon microspheres by the W ion-imprinted method can be used as the selective adsorbent for the removal of copper ions from wastewater.
2015, 32(11): 1312-1318
doi: 10.11944/j.issn.1000-0518.2015.11.150138
Abstract:
Hydroxylammonium sulfate(HAS) and cyclohexanone oxime(CHO) are difficult to be separated in acidic media in the hydrolysis of CHO. Thus,it is difficult to determinate HAS accurately by redox titration method due to the interference of CHO. A simple and efficient approach for simultaneous determination of HAS and CHO in the hydrolysis reaction of CHO was successfully developed by combining redox titration and high performance liquid chromatography in this article. With the concentration of H+ over 2.4 mol/L and the molar ratio of Fe3+ to CHO over 5:1,the relative standard deviation are 0.39% and 0.50%,and the correlation coefficients are 0.99998 and 0.99996 for five determinations of CHO and HAS,respectively. The recoveries of test samples are between 97.1% and 100.6%.
Hydroxylammonium sulfate(HAS) and cyclohexanone oxime(CHO) are difficult to be separated in acidic media in the hydrolysis of CHO. Thus,it is difficult to determinate HAS accurately by redox titration method due to the interference of CHO. A simple and efficient approach for simultaneous determination of HAS and CHO in the hydrolysis reaction of CHO was successfully developed by combining redox titration and high performance liquid chromatography in this article. With the concentration of H+ over 2.4 mol/L and the molar ratio of Fe3+ to CHO over 5:1,the relative standard deviation are 0.39% and 0.50%,and the correlation coefficients are 0.99998 and 0.99996 for five determinations of CHO and HAS,respectively. The recoveries of test samples are between 97.1% and 100.6%.
2015, 32(11): 1319-1326
doi: 10.11944/j.issn.1000-0518.2015.11.150157
Abstract:
The non-isothermal crystallization behavior of waterborne polyurethane/functionalized graphene nanocomposites(WPU/FGNs) was studied by differential scanning calorimetry(DSC). The non-isothermal crystallization kinetics of WPU/FGNs was investigated by Ozawa and Mo equations,and the crystallization activation energies were calculated by Kissinger equation. The results show that FGNs can be used as heterogeneous nucleation agent to increase the onset of crystallization temperature,peak temperature and crystallization rate of WPU during non-isothermal crystallization process of WPU/FGNs. Crystallization dimension of the composites increases with the increase of the mass fraction of FGNs. When the mass fraction of FGNs increases to 0.3%,crystallization activation energy of the composite decreases from -47.74 k J/mol to -53.60 k J/mol. When the mass fraction of FGNs is 1.0%,the crystallization activation energy of the composite increases to -41.74 k J/mol.
The non-isothermal crystallization behavior of waterborne polyurethane/functionalized graphene nanocomposites(WPU/FGNs) was studied by differential scanning calorimetry(DSC). The non-isothermal crystallization kinetics of WPU/FGNs was investigated by Ozawa and Mo equations,and the crystallization activation energies were calculated by Kissinger equation. The results show that FGNs can be used as heterogeneous nucleation agent to increase the onset of crystallization temperature,peak temperature and crystallization rate of WPU during non-isothermal crystallization process of WPU/FGNs. Crystallization dimension of the composites increases with the increase of the mass fraction of FGNs. When the mass fraction of FGNs increases to 0.3%,crystallization activation energy of the composite decreases from -47.74 k J/mol to -53.60 k J/mol. When the mass fraction of FGNs is 1.0%,the crystallization activation energy of the composite increases to -41.74 k J/mol.
2015, 32(11): 1327-1334
doi: 10.11944/j.issn.1000-0518.2015.11.150094
Abstract:
In order to improve the working voltage of electrochemical capacitors,LiNi0.5Mn1.5O4(LNMO) was employed as the positive electrode material and activated carbon(AC) was used as the negative electrode material for the asymmetric electrochemical capacitors and the optical conditions was explored. Enhancing the mass ratio of AC/LNMO and the voltage ranges could both increase the discharge capacity and energy density.At the AC/LNMO mass ratio of 4 and in the 0~3 V voltage range,97.5% capacity retention was achieved after 700 cycles at current density of 1×10-3A/cm2. Three-electrode system and electrochemical impedance spectroscopy were applied to explore the degradation of AC anode,and we also analyzed its influence in the AC/LNMO asymmetric capacitors.
In order to improve the working voltage of electrochemical capacitors,LiNi0.5Mn1.5O4(LNMO) was employed as the positive electrode material and activated carbon(AC) was used as the negative electrode material for the asymmetric electrochemical capacitors and the optical conditions was explored. Enhancing the mass ratio of AC/LNMO and the voltage ranges could both increase the discharge capacity and energy density.At the AC/LNMO mass ratio of 4 and in the 0~3 V voltage range,97.5% capacity retention was achieved after 700 cycles at current density of 1×10-3A/cm2. Three-electrode system and electrochemical impedance spectroscopy were applied to explore the degradation of AC anode,and we also analyzed its influence in the AC/LNMO asymmetric capacitors.
2015, 32(11): 1335-1342
doi: 10.11944/j.issn.1000-0518.2015.11.150142
Abstract:
Porous NiO film grown on the substrate of F-doped SnO2 conductive glasses(FTO) was successfully prepared through the hydrothermal method in combination with high temperature calcination. The surface morphology,phase composition and the valence state of the obtained NiO film were detected by SEM,TEM,XRD and XPS,respectively. The electrochemical performances were characterized by cyclic voltammetry(CV) and galvanostatic charge/discharge in the electrolyte solution of 6 mol/L KOH. These results indicate that the specific capcacitance of the NiO electrode can reach 651.6 F/g at a current density of 2 A/g. After 1000 cycles 71.6% of the maximum capcacitance is still remained,suggesting its excellent cycling stability and promising application as an ideal electrode material for supercapacitors.
Porous NiO film grown on the substrate of F-doped SnO2 conductive glasses(FTO) was successfully prepared through the hydrothermal method in combination with high temperature calcination. The surface morphology,phase composition and the valence state of the obtained NiO film were detected by SEM,TEM,XRD and XPS,respectively. The electrochemical performances were characterized by cyclic voltammetry(CV) and galvanostatic charge/discharge in the electrolyte solution of 6 mol/L KOH. These results indicate that the specific capcacitance of the NiO electrode can reach 651.6 F/g at a current density of 2 A/g. After 1000 cycles 71.6% of the maximum capcacitance is still remained,suggesting its excellent cycling stability and promising application as an ideal electrode material for supercapacitors.
