Artificial Graphite - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Artificial Graphite

The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

Jie Li – 1st expert on this subject based on the ideXlab platform

  • lipf6 and lithium oxalyldifluoroborate blend salts electrolyte for lifepo4 Artificial Graphite lithium ion cells
    Journal of Power Sources, 2010
    Co-Authors: Zhian Zhang, Jie Li, Xujie Chen, Fanqun Li, Xinyu Wang

    Abstract:

    Abstract The electrochemical behaviors of LiPF 6 and lithium oxalyldifluoroborate (LiODFB) blend salts in ethylene carbonate + propylene carbonate + dimethyl carbonate (EC + PC + DMC, 1:1:3, v/v/v) for LiFePO 4 /Artificial Graphite (AG) lithium-ion cells have been investigated in this work. It is demonstrated by conductivity test that LiPF 6 and LiODFB blend salts electrolytes have superior conductivity to pure LiODFB-based electrolyte. The results show that the performances of LiFePO 4 /Li half cells with LiPF 6 and LiODFB blend salts electrolytes are inferior to pure LiPF 6 -based electrolyte, the capacity and cycling efficiency of Li/AG half cells are distinctly improved by blend salts electrolytes, and the optimum LiODFB/LiPF 6 molar ratio is around 4:1. A reduction peak is observed around 1.5 V in LiODFB containing electrolyte systems by means of CV tests for Li/AG cells. Excellent capacity and cycling performance are obtained on LiFePO 4 /AG 063048-type cells tests with blend salts electrolytes. A plateau near 1.7–2.0 V is shown in electrolytes containing LiODFB salt, and extends with increasing LiODFB concentration in charge curve of LiFePO 4 /AG cells. At 1 C discharge current rate, the initial discharge capacity of 063048-type cell with the optimum electrolyte is 376.0 mAh, and the capacity retention is 90.8% after 100 cycles at 25 °C. When at 65 °C, the capacity and capacity retention after 100 cycles are 351.3 mAh and 88.7%, respectively. The performances of LiFePO 4 /AG cells are remarkably improved by blending LiODFB and LiPF 6 salts compared to those of pure LiPF 6 -based electrolyte system, especially at elevated temperature to 65 °C.

  • LiPF6 and lithium oxalyldifluoroborate blend salts electrolyte for LiFePO4/Artificial Graphite lithium-ion cells
    Journal of Power Sources, 2010
    Co-Authors: Zhian Zhang, Jie Li, Xujie Chen, Fanqun Li, Xinyu Wang

    Abstract:

    Abstract The electrochemical behaviors of LiPF 6 and lithium oxalyldifluoroborate (LiODFB) blend salts in ethylene carbonate + propylene carbonate + dimethyl carbonate (EC + PC + DMC, 1:1:3, v/v/v) for LiFePO 4 /Artificial Graphite (AG) lithium-ion cells have been investigated in this work. It is demonstrated by conductivity test that LiPF 6 and LiODFB blend salts electrolytes have superior conductivity to pure LiODFB-based electrolyte. The results show that the performances of LiFePO 4 /Li half cells with LiPF 6 and LiODFB blend salts electrolytes are inferior to pure LiPF 6 -based electrolyte, the capacity and cycling efficiency of Li/AG half cells are distinctly improved by blend salts electrolytes, and the optimum LiODFB/LiPF 6 molar ratio is around 4:1. A reduction peak is observed around 1.5 V in LiODFB containing electrolyte systems by means of CV tests for Li/AG cells. Excellent capacity and cycling performance are obtained on LiFePO 4 /AG 063048-type cells tests with blend salts electrolytes. A plateau near 1.7–2.0 V is shown in electrolytes containing LiODFB salt, and extends with increasing LiODFB concentration in charge curve of LiFePO 4 /AG cells. At 1 C discharge current rate, the initial discharge capacity of 063048-type cell with the optimum electrolyte is 376.0 mAh, and the capacity retention is 90.8% after 100 cycles at 25 °C. When at 65 °C, the capacity and capacity retention after 100 cycles are 351.3 mAh and 88.7%, respectively. The performances of LiFePO 4 /AG cells are remarkably improved by blending LiODFB and LiPF 6 salts compared to those of pure LiPF 6 -based electrolyte system, especially at elevated temperature to 65 °C.

  • lithium oxalyldifluoroborate carbonate electrolytes for lifepo4 Artificial Graphite lithium ion cells
    Journal of Power Sources, 2010
    Co-Authors: Jie Li, Zhian Zhang, Fanqun Li, Xujie Chen

    Abstract:

    Abstract The electrolytes based on lithium oxalyldifluoroborate (LiODFB) and carbonates have been systematically investigated for LiFePO 4 /Artificial Graphite (AG) cells, by ionic conductivity test and various electrochemical tests, such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge test. The conductivity of nine electrolytes as a function of solvent composition and LiODFB salt concentration has been studied. The coulombic efficiency of LiFePO 4 /Li and AG/Li half cells with these electrolytes have also been compared. The results show that 1 M LiODFB EC/PC/DMC (1:1:3, v/v) electrolyte has a relatively higher conductivity (8.25 mS cm −1 ) at 25 °C, with high coulombic efficiency, good kinetics characteristics and low interface resistance. With 1 M LiODFB EC/PC/DMC (1:1:3, v/v) electrolyte, LiFePO 4 /AG cells exhibit excellent capacity retention ∼92% and ∼88% after 100 cycles at 25 °C and at elevated temperatures up to 65 °C, respectively; The LiFePO 4 /AG cells also have good rate capability, the discharge capacity is 324.8 mAh at 4 C, which is about 89% of the discharge capacity at 0.5 C. However, at −10 °C, the capacity is relatively lower. Compared with 1 M LiPF 6 EC/PC/DMC (1:1:3, v/v), LiFePO 4 /AG cells with 1 M LiODFB EC/PC/DMC (1:1:3, v/v) exhibited better capacity utilization at both room temperature and 65 °C. The capacity retention of the cells with LiODFB-based electrolyte was much higher than that of LiPF 6 -based electrolyte at 65 °C, while the capacity retention and the rate capacity of the cells is closed to that of LiPF 6 -based electrolyte at 25 °C. In summary, 1 M LiODFB EC/PC/DMC (1:1:3, v/v) is a promising electrolyte for LiFePO 4 /AG cells.

Yushiang Wu – 2nd expert on this subject based on the ideXlab platform

  • Electrochemical characterization with homopolymer of 2-propen-1-amine coating on Artificial Graphite/carbon/silicon composites as anode materials for lithium ion batteries
    Journal of Alloys and Compounds, 2012
    Co-Authors: Yushiang Wu

    Abstract:

    Abstract This study reports the coating of spherical Artificial Graphite/disordered carbon/silicon (AG/C/Si) with a homopolymer of 2-propen-1-amine (PAA) layer. Transmission electron microscopy (TEM) observations clearly showed that the surface of the particle was coated with an amorphous layer of PAA-coated AG/C/Si composites. The resulting PAA-coated AG/C/Si electrode structure did not destroy locally because of large volume change. For both charge and discharge at 0.1 C, the PAA-coated AG/C/Si yielded the first columbic efficiency of approximately 89.1% and the first irreversible capacity decreased from 95.1 to 55.0 mAh g−1. Moreover, the discharge capacity was 410.1 mAh g−1 after 50 cycles, and its capacity retention increased to 91.5%. The addition of PAA decreased the specific surface area (BET) of the AG/C/Si composites and reduced the direct contact between the anode electrode surface and the electrolyte. These results indicate that PAA-coated AG/C/Si composites have relatively lower electrochemical resistance and favorable cycling stability.

  • electrochemical characterization with homopolymer of 2 propen 1 amine coating on Artificial Graphite carbon silicon composites as anode materials for lithium ion batteries
    Journal of Alloys and Compounds, 2012
    Co-Authors: Yushiang Wu

    Abstract:

    Abstract This study reports the coating of spherical Artificial Graphite/disordered carbon/silicon (AG/C/Si) with a homopolymer of 2-propen-1-amine (PAA) layer. Transmission electron microscopy (TEM) observations clearly showed that the surface of the particle was coated with an amorphous layer of PAA-coated AG/C/Si composites. The resulting PAA-coated AG/C/Si electrode structure did not destroy locally because of large volume change. For both charge and discharge at 0.1 C, the PAA-coated AG/C/Si yielded the first columbic efficiency of approximately 89.1% and the first irreversible capacity decreased from 95.1 to 55.0 mAh g−1. Moreover, the discharge capacity was 410.1 mAh g−1 after 50 cycles, and its capacity retention increased to 91.5%. The addition of PAA decreased the specific surface area (BET) of the AG/C/Si composites and reduced the direct contact between the anode electrode surface and the electrolyte. These results indicate that PAA-coated AG/C/Si composites have relatively lower electrochemical resistance and favorable cycling stability.

  • spheroidization modification of Artificial Graphite applied as anode materials for high rate lithium ion batteries
    Advanced Materials Research, 2011
    Co-Authors: Yushiang Wu

    Abstract:

    Rate capability tests showed that Artificial Graphite after spheroidization treatment exhibited a higher capacity in the higher C-rate region (2~10C) at a 0.1 C rate charge and variable C-rates discharge. Artificial Graphite after spheroidization treatment exhibited a higher capacity in the higher C-rate region (0.5~9 C) at the same C-rate charge and discharge. These results show that Artificial Graphite after spheroidization treatment has a large amount of isotropic microstructures that lithium ions can intercalate into the graphene layers from all directions via edge-plane surfaces. Therefore, the Artificial Graphite is more suitable than natural Graphite for the anode materials of high rate batteries.

Liquan Chen – 3rd expert on this subject based on the ideXlab platform

  • storage behavior of lini1 3co1 3mn1 3o2 Artificial Graphite li ion cells
    Electrochimica Acta, 2009
    Co-Authors: Chenghuan Huang, Liquan Chen, Kelong Huang, Yuqun Zeng

    Abstract:

    A series of Li-ion cells containing LiNi1/3Co1/3Mn1/3O2 and Artificial Graphite as the active materials, have been stored at various temperatures from 0 to 70 degrees C. The 3-electrode impedance study shows that both the solid electrolyte interphase (SEI) film resistance and charge-transfer resistance of the negative electrode first decrease and then increase during storage at 70 degrees C, while both resistances for the positive electrode increase under this condition. The reversible capacity loss of the 3-electrode cell, which is possibly attributed to dissolution of SEI film, accounts for over half of the total capacity loss after 5 weeks of storage. Gases generated from the swelling aged cell at 60 degrees C are mainly attributed to the reduction of the electrolyte on the negative electrode. A further study on the side-reaction has been done on Graphite electrodes and separators, indicating that SEI films may be rearranged and reformed on negative electrodes, and that some pores on the positive electrode side of separator are blocked due to the oxidation of electrolyte. resulting in poor Li-ion transfer and rise of the ohmic resistance during storage at elevated temperature. However, at 0 degrees C, this side-reaction is impeded. (C) 2009 Published by Elsevier Ltd.

  • Storage behavior of LiNi1/3Co1/3Mn1/3O2/Artificial Graphite Li-ion cells
    Electrochimica Acta, 2009
    Co-Authors: Chenghuan Huang, Kelong Huang, Yuqun Zeng, Liquan Chen

    Abstract:

    A series of Li-ion cells containing LiNi1/3Co1/3Mn1/3O2 and Artificial Graphite as the active materials, have been stored at various temperatures from 0 to 70 degrees C. The 3-electrode impedance study shows that both the solid electrolyte interphase (SEI) film resistance and charge-transfer resistance of the negative electrode first decrease and then increase during storage at 70 degrees C, while both resistances for the positive electrode increase under this condition. The reversible capacity loss of the 3-electrode cell, which is possibly attributed to dissolution of SEI film, accounts for over half of the total capacity loss after 5 weeks of storage. Gases generated from the swelling aged cell at 60 degrees C are mainly attributed to the reduction of the electrolyte on the negative electrode. A further study on the side-reaction has been done on Graphite electrodes and separators, indicating that SEI films may be rearranged and reformed on negative electrodes, and that some pores on the positive electrode side of separator are blocked due to the oxidation of electrolyte. resulting in poor Li-ion transfer and rise of the ohmic resistance during storage at elevated temperature. However, at 0 degrees C, this side-reaction is impeded. (C) 2009 Published by Elsevier Ltd.