High power nano-structured V2O5 thin film cathodes by atomic layer deposition

Abstract

Atomic layer deposition (ALD) has been used to prepare nano-structured cathode films for Li-ion batteries of V₂O₅ from VO(thd)₂ and ozone at 215 °C. The resulting films were strongly textured and rough without application of a template. The best electrochemical performance was observed for 10 nm nano-structured V₂O₅, that could sustain discharge rates up to 960 C while maintaining 20% of the initial 1 C capacity. The optimized cathode endured a discharge rate of 120 C for more than 1500 cycles while maintaining more than 80% of capacity, proving the rare combination of both high discharge rates and long life time simultaneously. The growth mechanism of the VO(thd)₂ and ozone provides a highly textured surface consisting of platelets of V₂O₅ providing a large contact area towards the electrolyte. The current V₂O₅ films show potential as cathodes in thin film micro batteries.