NiO is a typical material for new p-type oxide semiconductors. Conductivity of NiO can be raised with Li+ doping. In case of Li-heavy doping, we can obtain LixNiO2(0.5< × <1.0). Recently the importance of LiNiO2 has been increased as an electrode material for rechargeable lithium cells.

In this work, we tried to fabricate a novel NiO material with Li+-heavily doped by applying the pulsed laser-induced room temperature (R.T.) film process. Previously, we have succeeded in the epitaxial growth of various oxide thin films at R.T. such as Sn-doped In2O3 transparent electrodes [1]. Although the many studies have been made on the deposition of NiO epitaxial thin film at low temperatures [2], there are few reports on fabrication and the conductive characteristic for Li-heavily doped NiO epitaxial films. The film deposition at R.T., which is the unequilibrium vapor phase process, is expected to result in different crystal structure and characteristics from the films grown at high-temperatures.

A composition-adjusted thin film of LixNi1-xO(0.10< × <0.40) was deposited on a sapphire (α-Al2O3)(0001) or MgO(100) substrates by pulsed laser deposition (PLD) technique in 10−6 Torr of oxygen at R.T. and the high temperatures of 350 and 515°C. Crystalline properties of thin films deposited at R.T. or high temperatures were examined using reflection high energy electron diffraction (RHEED) and X-ray diffraction. For the Li-heavily doped NiO films(x>0.30) grown at R.T., a clear streak RHEED pattern showing epitaxial growth was observed. But the Li-heavily doped NiO films grown at high temperatures, exhibited the ring RHEED pattern, which indicates the policrystal growth of films. Electric conductivity of various Li-doped NiO thin films deposited at R.T. or high temperatures on sapphire (0001) substrates were measured by two-probe method. The interesting results were obtained that conductivity of the film was increased remarkably with an increase of Li-doping for R.T. deposition, but was not changed so much regardless of Li-doping for high-temperature depositions.

Supercapacitors and advanced batteries capable of rapid charge and discharge need conductive three dimensional porous electrodes. The high conductivities of porous metal electrodes are attractive. However, the surface areas of such electrodes are still well short of those achievable in carbon. One approach to formation of high surface area porous metal electrodes is to electrodeposit metal into nanostructured templates on 3-D scaffolds such as nickel foam. By careful control of composition and voltage thin films of mesoporous silica can be deposited onto these 3-D templates. Removal of the templating surfactant produces a very high surface area mesoporous coating. Metal can then be plated into the mesoporous silica, which, after removal of the silica, leaves a high surface area 3-D porous electrode.