Si film electrodes prepared on discontinuous current collector

Discontinuous Si film electrodes with 400, 800, and 1700 μm discontinuous lines (break lines) were fabricated by a simple masking and etching process. The structural and electrochemical properties of continuous and discontinuous Si film electrodes were investigated by means of optical microscopy, field emission scanning electron microscopy, X-ray diffraction, and charge-discharge tests. Although all electrodes showed similar first-charge capacities in the range of 210-230 μAh/g, the discontinuous electrode exhibited improved coulombic efficiency and cyclability when compared to the continuous electrode. Up to 100 cycles, the discontinuous electrode with the shortest line distance of 400 μm demonstrated the highest efficiency (95.2%) and capacity retention (89%). Observation of the cycled Si film electrodes revealed that discontinuity enhanced the structural stability of the electrode during the charge-discharge process.