(503c) Nitride-Rich Silicon Anodes for Lithium Rechargeable Batteries

There are growing research interests in developing high energy density lithium ion batteries with stable cycling performances and longer cycle life. Silicon is a potential candidate for an anode material due to its theoretical specific capacity (4,200 mAh/g), which is more than ten times the value of the currently used anode material, graphite (370 mAh/g). One of the main challenges for silicon as an anode material is its huge volume expansion (~400%) upon the formation of silicon-lithium alloys, resulting in the pulverization of electrodes and performance degradation. Due to this, strategies have led to the use of nano-sized Si morphologies to improve the cyclic performance. This paper reports two efforts in synthesizing nitride-rich silicon anodes through (1) plasma enhanced chemical vapor deposition (PECVD) and (2) chemical vapor deposition (CVD) routes. The PECVD films were deposited on surface treated copper current collectors as an amorphous anode material. The CVD route uses NH₃ as the nitride source to dope silicon nanoparticles, where they were then dispersed within a graphene matrix to form a composite anode. These anode materials were investigated by spectroscopy, microscopy and electrochemical techniques to characterize their composition and performance. The potential of these materials to produce anodes that display better volume stress management and thus improve the overall electrochemical cycling stability is presented.