Electrochemical properties of the Si thin-film anode deposited on Ti-Nb-Zr shape memory alloy in Li-ion batteries

Abstract

Lithium-ion batteries (LIBs) are widely used, and extensive research has been conducted on new electrode materials. Silicon has been widely studied as an anode material. However, Si has a problem which is the large volume expansion. This study improved the electrochemical properties of Si thin films by employing a Ti-Nb-Zr SMA as a replacement candidate. The electrodes were prepared using two-step DC magnetron sputtering, followed by heat treatment to improve the adhesion between the Si thin film and the Ti-Nb-Zr film of the electrodes. X-ray diffraction confirmed that the SMA changed from the β (BCC) phase structure to the α (HCP) crystalline phase because of the volume changes arising from the Li-Si reactions during the lithiation/delithiation process. Additionally, the heat treatment significantly improved the adhesion between the active materials and substrate, improving the internal charge transfer bond and the martensite properties of the alloy allows it to work in the full sense. This study highlights a high-capacity, long cycle life, and free-standing electrode improvement by combining the shape-memory behavior recrystallization mechanism of heat-treated superelastic passive Ti-Nb-Zr for Si anode materials.