High Charge-discharge Efficiency Research Articles

Novel Polypyrrole/Mesoporous Carbon Nanocomposite Electrode for an Electrochemical Hybrid Capacitor

With mesoporous carbon(CMK-3) serving as a support,we prepared a novel nanocomposite of polypyrrole/mesoporous carbon(PPy-CMK-3) by an in situ chemical polymerization method.An electrochemical hybrid capacitor was successfully designed using a PPy-CMK-3 composite and CMK-3 as positive and negative electrodes,respectively.The electrochemical capacitance performance of this kind of hybrid capacitor was investigated in 1.0 mol·L-1 NaNO3 electrolyte solution.The discharge capacity of the hybrid capacitor reached 57 F·g-1 under a current density of 5.0 mA·cm-2 and cell voltage of 1.4 V.The energy density of the hybrid capacitor reached 17 Wh· kg-1 with a power density of 2.5×102 W·kg-1.When the current density was increased from 5.0 to 50 mA·cm-2,the capacity of the hybrid capacitor remained at about 80% and it showed excellent high rate charge-discharge performance.Furthermore,the PPy-CMK-3/CMK-3 hybrid capacitor containing this PPy-CMK-3 nanocomposite could be active easily and it possessed a high charge-discharge efficiency and good cycle performance.

Effects of Synthesis Methods on Li1 + xV3O8 as Cathodes in Lithium-Ion Batteries

Lithiated vanadium oxides as promising cathode materials for secondary lithium batteries are prepared using several methods. The crystalline phase is characterized by powder X-ray diffraction, and the morphology is observed by scanning electron microscopy. The electrochemical properties of synthesized samples are systematically investigated by galvanostatic charge and discharge. The maximal initial specific discharge capacity belongs to the material produced by the hydrothermal route, which can attain at a current density of . The aqueous precipitation route produced a sample that exhibits the best cycling behavior among these lithium trivanadate samples, which keeps as 92% of its initial capacity after 20 cycles and preserves a high charge–discharge efficiency of around 99%.

High-energy density in aromatic polyurea thin films

This letter investigates dielectric responses of aromatic polyurea thin films fabricated through vapor deposition polymerization. The high quality polymer films exhibit high breakdown field (800 MV/m) and high-energy density (>12 J/cm3) at room temperature. These values decrease slightly from room temperature to 180 °C. Linear dielectric responses were found in the films even under high fields and high temperatures with a high charge-discharge efficiency (>90%). These high performance features make aromatic polyurea attractive for high-energy density capacitors, especially under high temperatures.

Feasibility of an Interpenetrated Polymer Network System Made of Di-block Copolymer Composed of Polyethylene Oxide and Polystyrene as the Gel Electrolyte for Lithium Secondary Batteries

The feasibility of a di-block copolymer, composed of a polyethylene oxide (PEO) chain and a polystyrene (PS) chain covalently bonded, as the gel electrolyte for lithium secondary batteries was investigated. The PEO-PS di-block copolymer gel electrolyte showed a high ionic conductivity of ∼1 mS/cm at room temperature. Moreover, it retained good mechanical strength within a co-continuous phase separated structure, and it suppressed the dendritic deposition of Li. Indications were that the interface between the electrolyte and the Li metal was chemically stable, as a result of the PEO phase fixed to PS by covalent bonding. In addition, it was indicated that the Li/PEOPS di-block copolymer gel electrolyte/LiFePO4 cell had a high charge-discharge efficiency of ∼99% during 30 cycles, while maintaining a discharge capacity of 124 mAh/g.

Li-LiFePO4 rechargeable polymer battery using dual composite polymer electrolytes

A composite polymer electrolyte, formed by dispersing into a poly(ethylene oxide)-lithium salt matrix two additives, i.e. calyx(6)pyrrole, (CP) acting as an anion trapper and superacid zirconia, S-ZrO2 acting as a conductivity promoter, has been tested as a separator in a new type of rechargeable lithium battery using lithium iron phosphate as the cathode. The choice of the electrolyte was motivated by its favourable transport properties both in terms of lithium ion transference number and of total ionic conductivity. The choice of the cathode was motivated by the value of its operating voltage which falls within the stability window of the electrolyte. The performance of the battery was determined by cycling tests carried out at various rates and at various temperatures. The results demonstrate the good rate capability of the battery which can operate at high charge-discharge efficiency even at 1 C rate and that it can be cycled at 90 °C with a satisfactory initial capacity of the order of 90 mAh g−1. These values outline the practical relevance of the composite electrolyte membrane and of its use as separator in a lithium battery.

Polyanthra[1,9,8-b,c,d,e][4,10,5-b,c,d,e]bis-[1,6,6a(6a-S) trithia]pentalene-active material for cathode of lithium secondary battery with unusually high specific capacity

Polyanthra[1,9,8-b,c,d,e][4,10,5-b,c,d,e]bis-[1,6,6a(6a-S)trithia]pentalene (PABTP) was prepared and investigated as cathode active material for lithium secondary batteries. The organic disulfide polymer was prepared by the direct sulfurization of anthracene and the oxidative coupling polymerization of the sulfide anthracene, characterized by FT-IR, Raman, elemental analysis, XPS and XRD. The polymer was used as cathode active material and the lithium secondary batteries were assembled and tested. The polymer had high specific capacity up to 1500 mAh g −1, which remained the value of 800 mAh g −1 at the 77th cycle, and kept high charge–discharge efficiency of 85% in the whole test.

Application of Li 3PO 4-Li 2S-SiS 2 glass to the solid state secondary batteries

Our previous study showed that lithium ion conductive glass, Li 3PO 4-Li 2S-SiS 2, has high ionic conductivity and high stability against electrochemical oxidation. Such stability will enable solid state batteries to be operated at high voltages. We constructed solid state batteries with LiCoO 2 as a positive electrode and indium as a negative electrode material, and investigated their performance. The operation voltage of In/LiCoO 2 cell was 3.5 V, which was a high voltage for a solid state battery. The cell showed its high charge-discharge efficiency and good cycling performance, and it was available at high current density (> 500 μA/cm 2). Its residual current under charging at constant voltage was extremely small so that it has high overcharge prevention.

Potentialities for saline water conversion and the provision of power in arid areas : Ward, Gerald T., Director of Research, Brace Research Institute, McGill University, Montreal, Canada, Technical Report No. T8, November, 1963, 12 pgs.

Our previous study showed that lithium ion conductive glass, Li3PO4-Li2S-SiS2, has high ionic conductivity and high stability against electrochemical oxidation. Such stability will enable solid state batteries to be operated at high voltages. We constructed solid state batteries with LiCoO2 as a positive electrode and indium as a negative electrode material, and investigated their performance. The operation voltage of In/LiCoO2 cell was 3.5 V, which was a high voltage for a solid state battery. The cell showed its high charge-discharge efficiency and good cycling performance, and it was available at high current density (> 500 μA/cm2). Its residual current under charging at constant voltage was extremely small so that it has high overcharge prevention.

Telstar I : National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland, June, 1963

Our previous study showed that lithium ion conductive glass, Li3PO4-Li2S-SiS2, has high ionic conductivity and high stability against electrochemical oxidation. Such stability will enable solid state batteries to be operated at high voltages. We constructed solid state batteries with LiCoO2 as a positive electrode and indium as a negative electrode material, and investigated their performance. The operation voltage of In/LiCoO2 cell was 3.5 V, which was a high voltage for a solid state battery. The cell showed its high charge-discharge efficiency and good cycling performance, and it was available at high current density (> 500 μA/cm2). Its residual current under charging at constant voltage was extremely small so that it has high overcharge prevention.