B. Purusottam Reddy

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.