Cycling Porous Silicon with Lithium Iron Phosphate for High Performance Li-Ion Batteries

Abstract

Silicon has drawn significant attention as an anode material for lithium ion batteries due to it significant capacity over carbon anode materials. Much of the literature as focused on cycling silicon with lithium-metal as the counter-electrode, which serves as an infinite source of lithium ions. We have recently shown that porous silicon is able to cycle at 1000 mAh/g at 1C for 600+ cycles against a lithium-metal counter-electrode. Here we will present the practical applicability and cycling performance of porous silicon with commercially available lithium-iron phosphate (LFP) cathodes. Having excess anode capacity is the standard widely used in industry with graphite-based lithium ion batteries to prevent lithium plating issue. However, we have observed that our porous silicon exhibits longer cycle life when the cathode capacity is in excess. This is likely due to the large consumption of lithium-ions during the formation of solid-electrolyte interface (SEI) layer. Our experiments will show that two different cycle performance based on either the anode or cathode in excess for the purpose of assembling a full-cell battery. Furthermore, a three-electrode test cell is used to monitor the I-V curves for each electrode independently to determine if lithium plating or other electrode degradation mechanisms occur.