Ag Doped Co3O4 Nanowire Arrays as an Electrode Material for Electrochemical Capacitors

2012 ◽  
Vol 268-270 ◽  
pp. 157-163 ◽  
Author(s):  
Yang Xu ◽  
Ji Chun Huang ◽  
Lin Cheng ◽  
Dian Xue Cao ◽  
Gui Ling Wang
Keyword(s):  
Electrochemical Impedance ◽  
Nickel Foam ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Method ◽  
Template Free ◽  
A Current ◽  
Charge Discharge ◽  
Discharge Test

Co3O4 nanowire arrays freely standing on nickel foam are prepared via a template-free growth method，and it is doped by Ag via electrodeposition method (denoted as NWA-Ag/Co3O4，NWA represents Nanowire Arrays). The morphology of NWA-Ag/Co3O4 is examined by scanning electron microscopy. The phase structure of the NWA-Ag/Co3O4 electrode is characterized by X-ray diffraction spectroscopy. The supercapacitance behavior of the NWA-Ag/Co3O4 electrodes is investigated by cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The results show that the nanowire arrays densely cover the nickel foam substrate and have diameters around 250 nm. The NWA-Ag/Co3O4 electrodes exhibit a specific capacitance of 1009 F g−1 at a current density of 5 mA cm-2 in 6.0 mol dm-3 KOH electrolyte. The capacitance loss is less than 6.5% after 500 charge/discharge cycles at 10 mA cm-2 and with columbic efficiency higher than 97.5%.

Preparation of Co-Ni Mixed Oxide/Graphene Composite and its Electrochemical Performances as Supercapacitor Material

2017 ◽  
Vol 727 ◽  
pp. 775-780 ◽  
Author(s):  
Yun Long Zhou ◽  
Chen Hao Zhao ◽  
Zhi Biao Hu ◽  
Xue Yan Huang ◽  
Kai Yu Liu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Mixed Oxides ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Graphene Composite ◽  
A Current ◽  
Charge Discharge ◽  
Discharge Test

The Co-Ni mixed oxides/graphene composite has been prepared using the solution based oxidation route. The structures of bare Co-Ni mixed oxides and Co-Ni mixed oxides/graphene composite is clearly studied by X-ray diffraction. The electrochemical properties of Co-Ni mixed oxides/graphene composite are investigated by Cyclic Voltammetry (CV) and galvanostatic charge discharge test. The result shows that, the NiO phase has not been detected in the composite, and the graphene composite delivers a discharge capacity of 353.6 F/g at a current density of 0.32 A g-1.

Hydrothermal Synthesis and Electrochemical Performance of LiFePO4/Graphene Composites for Lithium-Ion Batteries

2014 ◽  
Vol 900 ◽  
pp. 242-246 ◽  
Author(s):  
Xing Ling Lei ◽  
Hai Yan Zhang ◽  
Yi Ming Chen ◽  
Wen Guang Wang ◽  
Zi Dong Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Charge Discharge ◽  
Scanning Electron ◽  
Discharge Test

LiFePO4/graphene composites were prepared via a simple hydrothermal method. The as-prepared LiFePO4/graphene composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests. The lithium-ion batteries using LiFePO4/graphene composites as cathode material exhibited a discharge capacity of 165 mAh/g, which was 97% of the theoretical capacity of 170 mAh/g.

Preparation and Electrochemical Performance of Mn3O4/GR Composites Electrode Material in Supercapacitors

2019 ◽  
Vol 807 ◽  
pp. 50-56
Author(s):  
Yun Long Zhou ◽  
Zhi Biao Hu ◽  
Li Mei Wu ◽  
Jiao Hao Wu
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Precipitation Method ◽  
Electrochemical Performances ◽  
Manganese Sulfate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
A Current ◽  
Discharge Test

Using hydrated manganese sulfate and general type graphene (GR) as raw materials, Mn3O4/GR composite has been successfully prepared by the liquid phase chemical co-precipitation method at room temperature. X-ray diffraction (XRD) was used to investigate the phase structure of Mn3O4powder and Mn3O4/GR composite; The electrochemical performances of the samples were elucidated by cyclic voltammetry and galvanostatic charge-discharge test in 0.5 mol/L Na2SO4electrolyte. The results show that the Mn3O4/GR composite possesses graphene phase and good reversibility; the composite also displays a specific capacitance of 318.8 F/g at a current density of 1 A/g.

Electrochemical Performance Cr Doped Spinel LiMn2O4 Cathode for Lithium Ion Batteries

2014 ◽  
Vol 636 ◽  
pp. 49-53
Author(s):  
Si Qi Wen ◽  
Liang Chao Gao ◽  
Jia Li Wang ◽  
Lei Zhang ◽  
Zhi Cheng Yang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Cycle Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Discharge Test

To improve the cycle performance of spinel LiMn2O4as the cathode of 4 V class lithium ion batteries, spinel were successfully prepared using the sol-gel method. The dependence of the physicochemical properties of the spinel LiCrxMn2-xO4(x=0,0.05,0.1,0.2,0.3,0.4) powders powder has been extensively investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), charge-discharge test and electrochemical impedance spectroscopy (EIS). The results show that as Mn is replaced by Cr, the initial capacity decreases, but the cycling performance improves due to stabilization of spinel structure. Of all, the LiCr0.2Mn1.8O4has best electrochemical performance, 107.6 mAhg-1discharge capacity, 96.1% of the retention after 50 cycles.

Effects of Mg2+ Doping on the Properties of LiFePO4 Synthesized via Hydrothermal Route

2009 ◽  
Vol 610-613 ◽  
pp. 498-501
Author(s):  
Guang Chuan Liang ◽  
Xiao Ke Zhi ◽  
Xiu Qin Ou ◽  
Li Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Cell Volume ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Charge Discharge ◽  
Scanning Electron ◽  
Discharge Test

Mg2+ doped LiFePO4 was synthesized from Li3PO4, FeSO4 and MgSO4 by a hydrothermal synthesis at 150 °C（Li1-xMgxPO4, x=0.00, 0.01,0.02,0.04,0.06）. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and charge-discharge test. The results showed that Mg2+ dissolved in the LiFePO4 lattice. When the content is in the range of 0 to 6 mol%, Mg2+ caused the shrinkage of LiFePO4 cell volume. The capacity of doped and undoped samples at low discharging rate was similar, about 145mAhg-1 for 0.2C. But the sample doped with 2-4 mol% Mg2+ has higher capacity and longer cycle lifetime than the undoped one at 5C.

Preparation and Properties of Poly-2,5-dihydroxyaniline/Activated Carbon Composite Electrode

2012 ◽  
Vol 190-191 ◽  
pp. 528-533
Author(s):  
Miao Sun ◽  
Wei Wang ◽  
Ben Lin He ◽  
Ming Liang Sun ◽  
Fan Sun ◽  
...  
Keyword(s):  
Electrochemical Method ◽  
Composite Electrode ◽  
Electrochemical Impedance ◽  
Carbon Composite ◽  
Galvanostatic Charge ◽  
Acid Aqueous Solution ◽  
Carbon Composite Electrode ◽  
A Current ◽  
Charge Discharge ◽  
Discharge Test

Poly-2, 5-dimethoxyaniline (PDMA) coating was successfully prepared by electrochemical method on the surface of active carbon (AC) electrodes in oxalic acid aqueous solution. The resulted coating was hydrolyzed to produce poly-2,5-dihydroxyaniline (PDHA) to enhance the capacitance of the composite electrode. Scanning electron microscope (SEM), cyclic voltammetry (CV), galvanostatic charge/discharge test, and electrochemical impedance spectroscopy (EIS) were used to investigate the properties of these electrodes. A comparative analysis on the electrochemical properties of bare-carbon electrode was also conducted under similar conditions. The specific capacitance of the PDHA/AC composite electrode was 947.04 F•g-1 between 0.0 and 1.0 V at a current density of 3.0 mA•cm-2 in 0.5 M H2SO4 electrolyte. The capacitance retention of composite electrode was about 89.2% during 700 charge-discharge cycles.

Electrochemical Performance of Mg-Doped Li2FeSiO4/C as Cathode Material for Lithium-Ion Batteries

2013 ◽  
Vol 310 ◽  
pp. 90-94 ◽  
Author(s):  
Xiao Bing Huang ◽  
Hong Hui Chen ◽  
Huang Rong Li ◽  
Qian Peng Yang ◽  
Shi Biao Zhou ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Electrochemical Impedance Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Mg Doped ◽  
Discharge Test

Li2FeSiO4/C and Li1.97Mg0.03FeSiO4/C composites were successfully prepared by a solid-state method. Both samples were systematically investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), the charge-discharge test and electrochemical impedance spectra measurement, respectively. It was found that the Li1.97Mg0.03FeSiO4/C composite exhibited an excellent rate capability with a discharge capacity of 144mAh g-1 at 0.2C and 97mAh g-1 at 5C, and after 100 cycles at 1 C, 96% of its initial capacity was retained.

Surface Modification of Spinel LiMn2O4 with Y2O3 for Lithium-Ion Battery

2011 ◽  
Vol 391-392 ◽  
pp. 1069-1074 ◽  
Author(s):  
Ying Bai ◽  
Feng Wu ◽  
Hua Tong Yang ◽  
Yu Zhong ◽  
Chuan Wu
Keyword(s):  
Surface Modification ◽  
Chemical Process ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Discharge Characteristics ◽  
X Ray ◽  
Passivating Films ◽  
Discharge Capacities ◽  
Charge Discharge

Spinel LiMn2O4was modified with Y2O3coating by a chemical process. The crystal structures of the as-prepared samples were investigated by X-ray diffraction (XRD). The charge/discharge characteristics of the modified samples were evaluated at different rates between 3.0 and 4.4V. The discharge capacities of 2.0 wt.% Y2O3-coated LiMn2O4are 116 mAh•g−1, 99.7mAh•g−1, 93.3mAh•g−1and 82.9mAh•g−1at 0.1C, 0.5C, 1C and 2C rates (at 20◦C). The cycle abilities improvement of the spinel LiMn2O4coated with Y2O3are demonstrated at elevated temperature (55◦C) and high rates (2C). From the analysis of electrochemical impedance spectroscopy (EIS), the improvement of cycle ability may be attributed to the suppression on the formation of the passivating films and the reduction of Mn dissolution, which result from the surface modification with Y2O3.

Synthesis and Electrochemical Performance of K-Doped Li4Ti5O12 as Anode Material for Lithium-Ion Batteries

2014 ◽  
Vol 633-634 ◽  
pp. 495-498
Author(s):  
Xiao Bing Huang ◽  
Hong Hui Chen ◽  
Shi Biao Zhou ◽  
Yuan Dao Chen ◽  
Bei Ping Liu ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Rate Performance ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
State Method ◽  
Traditional Solid State Method ◽  
Initial Capacity ◽  
Charge Discharge ◽  
Discharge Test

Spinel Li4-xKxTi5O12(x=0, 0.03) were successfully synthesized by a traditional solid-state method and systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the charge-discharge test, respectively. The results demonstrated that Li3.97K0.03Ti5O12exhibited much better rate performance in comparsion with Li4Ti5O12. At 0.2 C and 10 C, it delivered a discharge capacity of 173 mAh g-1and 124 mAh g-1respectively, and after 100 cycles at 10 C, 96.1% of its initial capacity was retained.

Study of MnO2-Graphene Oxide nanocomposites for supercapacitor applications

MRS Advances ◽  
2019 ◽  
Vol 4 (13) ◽  
pp. 777-782 ◽  
Author(s):  
Rahul Singhal ◽  
Justin Fagnoni ◽  
David Thorne ◽  
Peter K. LeMaire ◽  
Xavier Martinez ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Characterizations ◽  
Average Diameter ◽  
Deionized Water ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supercapacitor Applications ◽  
A Current ◽  
Charge Discharge

ABSTRACTGraphene oxide (GO)/MnO2 nanocomposites were synthesized by adding KMnO4 in a solution of water and ethanol (3:1), containing 10 mg of GO. Brown precipitates were obtained after a continuous stirring for 1 hr. The precipitates were then washed with deionized water (DI) water and dried to obtain the MnO2-GO nanocomposites. Pure MnO2 was also synthesized using the same method without GO for the comparison. X-ray diffraction pattern confirm δ-MnO2 type of MnO2 with birnessite type MnO2 structure. The TEM images show the average diameter of MnO2 nanorods as 15 nm. Electrochemical characterizations were carried out in an aqueous solution of 3M KOH. Charge-discharge studies were carried out between 1A/g to 20 A/g current range. The MnO2-GO nanocomposites showed improved electrochemical performances. The capacitance of MnO2 and MnO2-GO electrodes was found to be as 300 F/g, and 350 F/g, respectively at a current of 0.5 A/g.

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