The effect of nitrogen on the cycling performance in thin-film Si1-xNx anode

The effects of nitrogen on the electrochemical properties of silicon-nitrogen (Si1-xNx)thin films were examined in terms of their initial capacities and cycling properties. In particular, Si0.76N0.24 thin films showed negligible initial capacity but an abrupt capacity increase to similar to 2300 mA h/g after similar to 650 cycles. The capacity of pure Si thin films was deteriorated to similar to 20% of the initial level after 200 cycles between 0.02 and 1.2 V at 0.5C (1C = 4200 mA/g), whereas the Si0.76N0.24 thin films exhibited excellent cycle-life performance after similar to 650 cycles. In addition, the Si0.76N0.24 thin films at 50 degrees C showed an abrupt capacity increase at an earlier stage of only similar to 30 cycles. The abnormal electrochemical behaviors in the Si0.76N0.24 thin films were demonstrated to be correlated with the formation of Li3N and Si3N4. (C) 2008 Elsevier Inc. All rights reserved.