JOURNAL OF ALLOYS AND COMPOUNDS, cilt.654, ss.363-370, 2016 (SCI-Expanded)
In the present work we proposed a new strategy to produce Si electrodes with high capacity retention. Si film with 20% at. Ag content is deposited by magnetron sputtering. The galvanostatic test result shows that the electrode delivers 1825 mAh g(-1) initially with 95% Coulombic efficiency and retains 96% of its initial discharge capacity after 60 cycles when cycled between 0.2-1.2 V. The same SiAg electrode performs 2500 mAh g(-1) as the first discharge capacity and quickly fails after 20 cycles when cycled between 0.005-1.2 V. Cyclic voltammetry and electrochemical impedance spectroscopy show that by proper selection of lower cut-off voltage (0.2 V), Ag particles remain inactive versus Li in cycling, which induces the distribution of finely dispersed active (Si) element with an inactive component (Ag) in the electrode.