Improving the durability of amorphous vanadium oxide thin-film electrode in a liquid electrolyte

We report on the effects of depositing a protective inorganic solid electrolyte LiAlF 4 coating on amorphous V 2 O 5 electrode in terms of long-term cycling efficiency and stability of the V 2 O 5 in a liquid electrolyte. Two V 2 O 5 thin-film electrodes were fabricated for extensive cyclic durability testing in a LiClO 4 /propylene carbonate liquid electrolyte: One V 2 O 5 film had no overlying coating while the other had a protective thin film of solid lithium ion conducting LiAlF 4 . The protected V 2 O 5 exhibited improved durability in terms of constant capacity with repeated cycling up to 800 cycles, while the uncoated V 2 O 5 electrode displayed significant capacity loss. Our results demonstrate that deposition of an inorganic solid electrolyte (LiAlF 4 ) on amorphous V 2 O 5 films serves as a protective overlayer and enhances the long-term cycling efficiency and stability of the V 2 O 5 in a liquid electrolyte.