[en] The effects of nitrogen on the electrochemical properties of silicon-nitrogen (Si_1-xN_x) thin films were examined in terms of their initial capacities and cycling properties. In particular, Si_0.76N_0.24 thin films showed negligible initial capacity but an abrupt capacity increase to ∼2300 mA h/g after ∼650 cycles. The capacity of pure Si thin films was deteriorated to ∼20% of the initial level after 200 cycles between 0.02 and 1.2 V at 0.5 C (1 C=4200 mA/g), whereas the Si_0.76N_0.24 thin films exhibited excellent cycle-life performance after ∼650 cycles. In addition, the Si_0.76N_0.24 thin films at 50 deg. C showed an abrupt capacity increase at an earlier stage of only ∼30 cycles. The abnormal electrochemical behaviors in the Si_0.76N_0.24 thin films were demonstrated to be correlated with the formation of Li₃N and Si₃N₄. - Graphical abstract: The Si_0.76N_0.24 thin films showed negligible initial capacity, but an abrupt capacity increase to ∼2300 mA h/g after ∼650 cycles, followed by excellent cycle-life performance. This abnormal electrochemical behavior was demonstrated to be correlated with the formation of Li₃N and Si₃N₄