A study on harvesting of PKL electricity

The efficiency of any electric cell or battery is very important. To keep it in mind it has been studied the columbic efficiency, voltaic efficiency and energy efficiency of a PKL (Pathor Kuchi Leaf) Quasi Voltaic Cell or Modified Voltaic Cell. It was found that the columbic efficiency data illustrated that this efficiency was lower comparing to other efficiencies may be the absence of salt bridge or separator between the electrodes. Because, our designed and fabricated PKL cell does not have any salt bridge. So that the internal resistance is lower than the traditional voltaic cell and as a result more current was found. The voltage and current changes with time and I–V characteristics for PKL unit cell, module, panel and array have also been studied. It is shown that the voltaic and energy efficiency have been studied. However, the highest efficiency was obtained for 40% PKL sap with 5% secondary salt in 55% aqueous solution, which implies that the concentration of PKL juice can play an important role regarding efficiency. It was also found that the average energy efficiency was 97.43% and it was also found that the average voltaic efficiency was 57.29%. Finally, morphological study FESEM (Field Emission Scanning Electron Microscopy) has also been performed. It is seen that the results confirmed that Zn was deposited on the Cu surface during the electro deposition process in PKL solution. Using AAS, it has been measured the concentration of [Cu2+] as a reactant ion and the concentration of [Zn2+] as a product ion those have been tabulated and graphically discussed. The variation of pH has also been studied with time and which was also tabulated and graphically discussed.

The improvement of pitch activation by graphene for long-cycle Li–S batteries

Pitch-derived graphene-carbon sheets with surface area of 2930 m2 g−1 and 71 wt% sulfur loading apply to Li–S batteries and exhibit >99.0% columbic efficiency over 1500 cycles.

Polypyrrole|zinc supercapattery with the aqueous electrolyte

Polypyrrole (PPY) electrode was obtained by electrochemical oxidative polymerization of pyrrole on graphite electrode from aqueous electrolyte containing 0.1 mol dm?3 pyrrole monomer and 1.0 mol dm?3 HCl. Polymerization was achieved at the constant current density of 2 mA cm?2 during 1 h. The estimated active mass of PPY (assuming that the maximal doping degree of 0.33 was achieved and the polymerization efficiency of 100%) was 14 mg. Electrochemical characterization of PPY electrode was performed by galvanostatic experiments of charge (doping) and discharge (dedoping) with different current densities in the range between 0.5 and 1.5 mA cm?2. The experiments were performed in aqueous electrolyte containing 2.0 mol dm?3 NH4Cl and 1.1 mol dm?3 ZnCl2. Based on galvanostatic charge/discharge curves, following parameters of PPY electrode were evaluated: discharge capacity, specific discharge capacity, charge capacity, specific charge capacity, and Columbic efficiency. Both charge and discharge capacities were dependent on charge/discharge currents. The values decreased by increasing charge/discharge current, except for the lowest current density where Columbic efficiency exceeded 100%, which was explained by involvement of cations, from the electrolyte, in the doping process. An electrochemical cell in which PPY electrode served as a cathode and zinc electrode as the anode with an aqueous electrolyte containing 2.0 mol dm?3 NH4Cl and 1.1 mol dm?3 ZnCl2, was formed and relevant electrochemical and electrical parameters of the cell were estimated and discussed. Charge of the Zn|PPY cell was dependent on the charge/discharge current. Charge of the cell started between 0.5 and 0.7 V and proceeded up to 1.5 V, while the open circuit voltage of the fully discharged cell was 1.3 V. Specific discharge capacity of Zn|PPY cell, calculated based on discharge times, ranged from 95 to 70 mA h g?1, decreasing linearly with increasing discharge current density. On the other hand, calculated values of the theoretical capacity of the Zn|PPY cell was 105 mA g?1, meaning that practically 90% of the theoretical capacity can be achieved by discharging the cell with low current densities, while 67% of the theoretical capacity was obtained with the highest used current density. Based on Ragon parameters, the estimated values of specific energy that ranged between 46 and 68 W h kg?1, and the specific power between 125 and 380 W kg?1, Zn|PPY cell might be classified as a ?supercapattery?.

Photovoltaically self-charging cells with WO3·H2O/CNTs/PVDF composite

Nanostructure improves the columbic efficiency of a freestanding WO3·H2O/CNTs/PVDF electrode as the energy storage part in PSCs.