Effects of Ni film thickness on the structural stability of Si/Ni/Cu film electrodes

The electrochemical properties of Si/Ni/Cu film electrodes fabricated with different Ni film thicknesses were evaluated by investigating their structural properties. As the Ni film thickness increased from 0.5 to 3.5 μm, the growth behavior of the Ni film was changed from a fine grain structure to a column structure grown preferentially. The morphology of Ni clusters was also changed from round to trigonal due to the increase of the interfacial energy between the Ni and the Cu increased greatly with increasing Ni film thickness. The formation of trigonal clusters in the 3.5-μm film reduced the stress in the film and enhanced the adhesion between the Si film and the Ni film. The structurally stabilized Si electrode with a 3.5-μm thick Ni film improved the electrochemical properties of the Li/Si thin film cell.