HWCVD MoO 3 nanoparticles and a-Si for next generation Li-ion anodes

Abstract

We have employed hot wire chemical vapor deposition (HWCVD) for the generation of MoO 3 nanostructures at high density. Furthermore, the morphology of the nanoparticles is easily tailored by altering the HWCVD synthesis conditions. The MoO 3 nanoparticles have been demonstrated as high-capacity Li-ion battery anodes for next-generation electric vehicles. Specifically, the MoO 3 anodes have been shown to have approximately three times the Li-ion capacity of commercially employed graphite anodes in thick electrodes suitable for vehicular applications. However because the materials are high volume expansion materials (≥ 100%), conformal Al 2O 3 coatings deposited with atomic layer deposition (ALD) were required before high rate capability was demonstrated. Recently, NREL is exploring high capacity Si anode materials that have a volume expansion of ~ 400%. It is assumed that new ALD coatings will need to be developed in order to stabilize Si as an anode material. Silicon is a superior choice for an anode material to the metal oxide structures due to both a higher capacity and a significantly lower hysteresis in the voltage vs. Li/Li + for the charge/discharge profiles.