Electrochemical Performance of AlÕMnO2 Dry Cells: An Alternative to Lechlanche Dry Cells

Aluminum-MnO2 �Al/MnO2� dry cells of “D” size configuration are investigated as an alternative to the Lechlanche dry cell, where aluminum is replaced for zinc as the anode, MnO2 as the cathode, and a mixture of aluminum chloride/ammonium chloride/chromium chloride as the electrolyte. Investigations regarding the optimization of conducting material, electrolyte composition, and electrochemical performance of the cell at different temperature and current drains �100, 200, and 400 mA� are carried out. Internal resistance and storage life of the fabricated aluminum dry cells are also evaluated. The results suggest that Al/MnO2 dry cells exhibit a superior performance than their Zn counterpar

Sol-Gel Synthesis of 5 V LiCuxMn2−xO4 as a Cathode Material for Lithium Rechargeable Batteries

Spinel LiCuxMn2−xO4 0.025 x 0.1 has been synthesized using oxalic acid as the chelating agent using a sol-gel method to obtain submicrometer-sized particles, good surface morphology, homogeneity, agglomeration, and high crystallinity involving short heating time. X-ray diffraction XRD, scanning electron microscopy SEM, Fourier transform infrared spectroscopy, and thermogravimetric and differential thermal analysis were carried out for the physical characterization of the synthesized powder. The XRD patterns of LiCuxMn2−xO4 show the single-phase spinel product, which is in good agreement with the JCPDS card 35-782. SEM images show that the particles, on the average, are of 50 nm in size and are present as agglomerated clusters at all dopant levels. Electrochemical cycling studies of the compound were carried out between 3 and 5 V to understand the redox behavior of Cu2+ ions. The charge–discharge cycling studies of spinel material with Cu stoichiometry of x = 0.1 calcined at 850°C exhibit an initial discharge capacity of 130 mAh g−1 and stabilized at 120 mAh g−1

Early ontogeny of foraging behaviour in the short-nosed fruit bat Cynopterus sphinx (Megachiroptera) : preliminary results

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Plant ecology meets animal cognition: impacts of animal memory on seed dispersal

We propose that an understanding of animal learning and memory is critical to predicting the impacts of animals on plant populations through processes such as seed dispersal, pollination and herbivory. Focussing on endozoochory, we review the evidence that animal memory plays a role in seed dispersal, and present a model which allows us to explore the fundamental consequences of memory for this process. We demonstrate that decision-making by animals based on their previous experiences has the potential to determine which plants are visited, which fruits are selected to be eaten from the plant and where seeds are subsequently deposited, as well as being an important determinant of animal survival. Collectively, these results suggest that the impact of animal learning and memory on seed dispersal is likely to be extremely important, although to date our understanding of these processes suffers from a conspicuous lack of empirical support. This is partly because of the difficulty of conducting appropriate experiments but is also the result of limited interaction between plant ecologists and those who work on animal cognition

Synthesis, Characterization, and Electrochemical Properties of LiCrxNiyMn2−x−yO4 Spinels as Cathode Material for 5 V Lithium Battery

Sol–gel assisted spinel LiCrxNiyMn2−x−yO4 0 x 0.4 and 0 y 0.4 has been synthesized. The thermal study of the precursor was carried out by thermogravimetric and differential thermal analyses. Furthermore, the material has been subjected to X-ray diffraction, scanning electron microscopy, Fourier transform IR spectroscopy analysis, X-ray photoelectron spectroscopy, cyclic voltammetry studies, and electrochemical charge–discharge studies. The X-ray diffraction of LiCrxNiyMn2−x−yO4 matches well with the Joint Committee on Powder Diffraction Standard card no. 35-782, confirming the formation of a single-phase spinel. Charge–discharge studies were carried out between 3 and 5 V to understand the electrochemical behavior of the undoped and doped spinels. LiCr0.25Ni0.25Mn1.5O4 calcined at 850°C possesses a particle size of around 70 nm and exhibits an initial discharge capacity of 105 mAh g−1 stabilizing at 98 mAh g−1 over the investigated 20 cycles. However, maleic acid derived LiCr0.25Ni0.25Mn1.5O4 delivers a stable higher discharge capacity of 115 mAh g−1 over the investigated 20 cycles and is a promising 5 V cathode material

Synthesis and Electrochemical Performance of High Voltage Cycling LiM0.05Co0.95O2 as Cathode Material for Lithium Rechargeable Cells

Substituted cobalt oxides, LiM0.05Co0.95O2 (M 5 Mg21, Al31, and Ti41), have been synthesized using solid-state technique and their performance in a 2032-type lithium rechargeable coin cell is reported. The synthesized powders were structurally analyzed using X-ray diffraction ~XRD! and the surface morphology evaluated with scanning electron microscopy. XRD patterns indicate that single-phase materials were formed involving Al-doped LiCoO2 . Electrochemical studies were carried out in the voltage range 3.5-4.5 V ~vs. Li metal! using 1 M LiPF6 in ethylene carbonate/dimethyl carbonate as electrolyte. The doping involving 5% Mg resulted in a charge/discharge capacity of ;160 mAh/g at C/5 rate and remained stable even after 50 cycles. To the best of our knowledge, this is the first time that such high stable capacities have been obtained involving doped LiCoO2 when cycled up to 4.5 V

Performance of meta-nitroaniline in magnesium reserve batteries

IV/-IAh Magnesium (Mg)/m-nitro aniline (MNA) cells have been constructed using Mg anode and MNA cathode. The cells were investigated for their performance behaviour at diffcrent current densities and with various aqueous magnesium electrolytes viz: magnesium chloride [MgCI2], Magnesium perchlorate IMg(CI0,l)2] and magnesium bromide [MgBr2], after initial standardization of the cathode mix. The discharge behaviour of the above magnesium cells are discussed in terms of cathodic efficiency of MNA. Cyclic voltammetric studies of MNA cells were carried out which indicates the irreversible natun: of the depolarizer

Investigations on magnesium polymer electrolytes

Synthesis and characterization of Polyethylene Oxide (PEO) blended with Magnesium salts viz, MgCI2, Mg(CIOJ2 are presented in this paper. Microstructural characterization was done using Fourier Transform Infra red spectroscopy (FTIR). AC impedance Technique was used for electrical characterization of the prepared polymer electrolytes. Discharge behaviour of Magnesium button cells assembled using the above polymer electrolytes are discussed in terms of capacity output. Preliminary investigations reveal the possibility of fabricating Magnesium Polymer batteries