SN-NI ALLOY THIN FILMS FOR ANODES TO BE USED IN LITHIUM-ION BATTERIES AND PROCESS FOR PREPARING THE SAME

摘要

The invention relates to a process for preparing thin films of alloys from Sn-Ni system, with a thickness ranging between 0.5...2 μ m, by vapor vacuum-deposition on a Cu or stainless steel conductive metallic layer, the claimed thin films being meant to be used for applications in the field of lithium-ion batteries, having high corrosion protection, or as decorative layers. According to the invention, the process has the following stages : preparing the starting material, namely Sn and Ni as chunks/grains, which are degreased by washing them with isopropyl alcohol and acetone and then dried, after which they are introduced in special smelting and evaporation crucibles of the deposition installation, preparing the Cu or stainless steel substrate foils with sizes of 2x6 cm and a thickness ranging between 0.2...0.5 mm, whose face exposed to uniformization is polished on sandpaper with increasing granulation, they are washed, degreased and dried again and then fixed by means of clips onto the substrate-holder plate of the deposition installation, the precinct of the installation is vacuumed to values ranging between 10... 10Torr, then the installation for heating the substrate-holder plate and the mechanism which rotates it are started, to heat the plate to a temperature of 20...200°C, followed by starting the process of melting and thermal evaporation of metals in a flux of electrons at intensities of 1...10 kW, and by deposition of thin films of alloys from Sn-Ni system, with a composition, expressed in weight percentage, of 60...65% Sn and 30...35% Ni, where the melting-evaporation intensity of Sn is of 1.5...2.5 kW and that of Ni is of 2...3 kW, at a temperature of the substrate ranging between 150...200°C.