Atomic layer deposition of Al₂O₃ on V₂O₅ xerogel film for enhanced lithium-ion intercalation stability Available to Purchase

V₂O₅ xerogel films were fabricated by casting V₂O₅ sols onto fluorine-doped tin oxide glass substrates at room temperature. Five, ten and twenty atomic layers of Al₂O₃ were grown onto as-fabricated films respectively. The bare film and Al₂O₃-deposited films all exhibited hydrous V₂O₅ phase only. Electrochemical impedance spectroscopy study revealed increased surface charge-transfer resistance of V₂O₅ films as more Al₂O₃ atomic layers were deposited. Lithium-ion intercalation tests at 600 mAg⁻¹ showed that bare V₂O₅ xerogel film possessed high initial discharge capacity of 219 mAhg⁻¹ but suffered from severe capacity degradation, i.e., having only 136 mAhg⁻¹ after 50 cycles. After deposition of ten atomic layers of Al₂O₃, the initial discharge capacity was 195 mAhg⁻¹ but increased over cycles before stabilizing; after 50 cycles, the discharge capacity was as high as 225 mAhg⁻¹. The noticeably improved cyclic stability of Al₂O₃-deposited V₂O₅ xerogel film could be attributed to the improved surface chemistry and enhanced mechanical strength. During repeated lithium-ion intercalation/de-intercalation, atomic layers of Al₂O₃ which were coated onto V₂O₅ surface could prevent V₂O₅ electrode dissolution into electrolyte by reducing direct contact between active electrode and electrolyte while at the same time acting as binder to maintain good mechanical contact between nanoparticles inside the film.