HWCVD MoO3 nanoparticles and a-Si for next generation Li-ion anodes

We have employed hot wire chemical vapor deposition (HWCVD) for the generation of MoO3 nanostructures at high density. Furthermore, the morphology of the nanoparticles is easily tailored by altering the HWCVD synthesis conditions. The MoO3 nanoparticles have been demonstrated as high-capacity Li-ion battery anodes for next-generation electric vehicles. Specifically, the MoO3 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 Al2O3 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.