Influence of Sputtering Conditions on Structural and Electrochemical Properties of the Si Anode Film for Lithium Secondary Batteries

Abstract

)Abstract This study investigated the dependence of the various sputtering conditions (Ar pressure:2~10 mTorr, Power: 50~150 W) and thickness (50~1200 nm) of Si thin film on the electrochemical properties,microstructural properties and the capacity fading of a Si thin film anode. A Si layer and a Ti buffer layerwere deposited on Copper foil by RF-magnetron sputtering. At 10 mTorr, the 50 W sample showed the bestcapacity of 3323 mAh/g, while the 100 W sample showed the best capacity retention of 91.7%, also at 10 mTorr.The initial capacities and capacity retention in the samples apart from the 50 W sample at 10 mTorr wereenhanced as the Ar pressure and power increased. This was considered to be related to the change of themicrostructure and the surface morphology by various sputtering conditions. In addition, thinner Si film anodesshowed better cycling performance. This phenomenon is caused by the structural stress and peeling off of theSi layer by the high volume change of Si during the charge/discharge process.Key wordslithium ion battery, silicon anode, deposition condition, sputtering.