O. M. Hussain

Electrochemical Performance of rf Magnetron Sputtered LiCoO{sub 2} Thin Film Positive Electrodes

Thin films of LiCoO2 were grown by rf magnetron sputtering technique and studied the influence of In situ annealing treatment on microstructural and electrochemical properties of the films. Annealing treatment in presence of O2 ambient develops characteristic (104) plan in relative to (003) plane texture indicating that the films have HT‐layered structure with R3¯m symmetry. The effect is discussed in terms of grain size, cycling stability, reversibility and the specific discharge capacity.

HT‐LiCoO2 Thin Film Positive Electrodes Prepared by RF Magnetron Sputtering

Thin films of LiCoO2 prepared by RF magnetron sputtering on Si/SiO2/Ti/Au substrates are investigated microstructural and electrochemical properties. The as deposited film shown layered with (003) preferred orientation. After annealing at 923 K in presence of O2 ambient (5×10−2 mbar), HT hexagonal phase LiCoO2 is obtained for the films deposited at O2 to Ar ratio 1:9 and at substrate temperature 523 K. LiCoO2 deposit is unambiguously shown two Raman bands at 465 and 545 cm−1 confirming layered hexagonal structure. Also, studied the performance of the LiCoO2 as positive electrode in aqueous (Pt// LiCoO2) and non‐aqueous (Li// LiCoO2) Li‐ion rechargeable batteries.

Electrical and electrochemical performance of Mn3O4 nanoparticles synthesized by hydrothermal method

Hausmannite Mn3O4 nanoparticles have been synthesized by a simple hydrothermal method at low temperature. The microstructural, electrical and dielectric properties were studied. The XRD data exhibited different diffraction peaks along with predominant (211) orientation corresponds to tetragonal structure of Mn3O4 with crystallite size of 65 nm. The SEM analysis reveals that the octahedral shape of grains with average grain size of 250 nm. The vibrational studies from Raman measurements confirmed the formation of Mn3O4. The impedance response of the Mn3O4 sample was studied over the frequency range of 1 Hz – 1 MHz in the temperature range from room temperature to 373 K. The conductivity of the sample was observed to be increased (1.86 × 10−5 S/m at 373 K) with temperature following the Arrhenius behavior with an estimated activation energy of 0.37 eV. The dielectric constant and dielectric loss were examined from 333K to 373K in the frequency range of 1 Hz – 1 MHz. The electrochemical performance of Mn3O4 ...

Pseudo capacitive performance of copper oxide thin films grown by RF sputtering

Thin films of Copper Oxide were prepared by radio frequency magnetron sputtering on steel substrates maintained at 250°C under different RF powers ranging from 150W to 250W by keeping the sputtering pressure at 5.7×10−3 mbar and O2:Ar ratio of 1:7. The influence of RF power on the pseudo capacitive performance of thin films was studied. The X-ray diffraction studies and Raman studies indicates that all the thin films exhibits CuO phase. The electrochemical studies was done by using three electrode configuration with platinum as reference electrode. From the cyclic voltammetry studies a high rate pseudocapacitance of 227 mFcm−2 at 0.5 mVs−1 and 77% of capacity retention after 1000 cycles was obtained for the CuO thin films prepared at an RF power of 220W.

Synthesis and electrochemical properties of layered structure Li[Ni0.5Co0.25Mn0.25]O2 cathode material

Lithium ion (Li-ion) batteries are currently the energy source of choice for cell phones, laptops, and other mobile electronic devices due to their balance of high energy density with high power density compared to other electrochemical energy carriers. In the present study, mixed hydroxide method is used to prepare Li[Ni0.5Co0.25Mn0.25]O2 from the precursors and analyze qualitatively and studied the electrochemical properties. The XRD spectrum exhibited predominant (003) orientation at 2θ =18.39o corresponding to hexagonal layered structure of R3m symmetry with evaluated lattice parameters are a= 2.84 A, c= 14.43 A. Raman measurements were performed to understand the microstructure and vibrational modes of the prepared sample. From the electrochemical (EC) studies an initial discharge capacity of about 140 mAhg−1 with good cyclic stability was observed for the prepared sample in the potential range 0.0 −1.0V in aqueous medium.

Characteristics of HT-LiCoO2 cathode films synthesized by Rf magnetron sputtering

Polycrystalline HT-LiCoO2 films were successfully synthesized by rf magnetron sputtering. The films were characterized by the studying their phase, structure, and morphology using ex-situ measurements of X-ray diffractometry (XRD), Raman Spectroscopy, Atomic force micrometry (AFM). Electrochemical performance evaluation indicated that the as grown LiCoO2 films The anodic electrochemical performances of the films have been evaluated by cyclic voltammetry (CV) at a scan rate of 0.5 mV/s and by galvanostatic cycling, with lithium metal as the counter and the reference electrode, and cycled in the range of 3.0 - 4.2 V at a current density of 50 μA/cm2. The films show a discharge capacity at the 20th cycle of 58 μAh cm−2μm− Keywords: LiCoO which exhibited excellent capacity retention with a small capacity fade which exhibited excellent capacity retention with a small capacity fade.