Fabrication of NiO nanowall electrodes for high performance lithium ion battery

We report the fabrication of vertically aligned NiO nanowalls on nickel foils using a plasma assisted oxidation method. Electrochemical properties of as-synthesized NiO nanowalls were evaluated by galvanostatic cycling and cyclic voltammetery. The results show a capacity of similar to 638 (mA h)/g (at 1.25C rate), with excellent capacity retention of up to 85 cycles, when cycled in the range, 0.005-3.0 V vs Li. The superior electrochemical performance of NiO nanowalls in comparison to the previously reported results on nanosized NiO particles can be attributed to its large surface area and shorter diffusion length for mass and charge transport. A possible reaction mechanism is discussed. We also report that electron field emission studies show that the verticllay aligned NiO nanowalls are efficient field emitters with a turn-on field of 7.4 V/mu m and a maximum current density of similar to 160 mu A/cm(2) can be achieved.