Electrochemical properties of Si film electrodes with TiNi shape memory alloy as a current collector

Abstract

The electrochemical and structural properties of Si thin film electrodes using a TiNi shape memory alloy as a current collector (substrate) are investigated with and without annealing. Annealed Si film electrodes exhibit an initial efficiency of 87% and a charge capacity retention (at the 50th cycle) of 85%. XRD results of the annealed Si film electrode during the charge-discharge process reveal the phase transformation (stress accommodation) of the TiNi substrate: cubic TiNi (initial) to monoclinic TiNi (after charge) and back to cubic TiNi (after discharge). SEM results of the annealed Si electrode show a remarkable reduction in structural damage of the Si film as compared to the as-deposited Si film electrode. The good electrochemical performances are ascribed to the high structural stability enhanced by both the post-annealing and stress accommodation of the TiNi substrate. (C) 2012 Elsevier B.V. All rights reserved.