Characteristics of LiNiO2 thin films synthesized by Li diffusion on the surface oxidized epitaxial layer of Ni-alloy

LiNiO2 thin films for the cathode application of the rechargeable battery were fabricated by the Li-ion diffusion on the surface oxidized NiO layer. Bi-axially textured Ni tapes with 50-80 mu m thickness were fabricated using cold rolling and annealing of Ni rods which were prepared by cold isostatic pressing (CIP) of Ni powder. Surface oxidation of Ni tapes were conducted using tube furnace or line-focused infrared (IR) heater at 900 degrees C for 150 s in flowing oxygen atmosphere. After Li was deposited on the NiO layer by thermal evaporation, LiNiO2 was formed by Li diffusion through the NiO layer during subsequent heat treatment using IR-heater with various heat treatment conditions. The reacted LiNiO2 region showed homogeneous composition throughout the thickness and did not show any noticeable defects frequently found in the solid state reacted LiNiO2. (c) 2007 Elsevier B.V. All rights reserved.