Characterization of a hybrid Li-ion anode system from pulsed laser deposited silicon on CVD-grown multilayer graphene

Abstract

A hybrid anode system for lithium (Li) ion battery applications based on pulsed laser deposited silicon films on chemical vapor deposited multilayer graphene (MLG) layers on a nickel foam substrate was electrochemically characterized. The as-grown material was directly fabricated into an anode without a binder, and tested in a half-cell configuration. There is evidence of the participation of both the multilayer graphene and the Si in the transport of Li ions. Even when cycled under stressful voltage limits that accelerate degradation, the MLG-Si films displayed higher stability than Si-only anodes, especially at higher cycling rates. Unlike the Si cells that display capacity fade even within the first few cycles, the MLG-Si cells show a very narrow spread in capacity, indicative of the role of the graphene layers in improving adhesion of the Si and acting as a compliant buffer for its volume expansion. Stable average specific capacities of ~1,200 mAh/g per total weight of MLG + Si, over 80 cycles at C/5 rate, were obtained for the MLG-Si anode. Pre- and post-cycling characterization of the anode materials revealed the differences between the two systems. © 2014 The Author(s).