Lithium intercalation and conduction in Fe-containing tantalum oxide films synthesized with an atmospheric pressure plasma jet

Abstract

Lithium ionic intercalation and conduction performance of tantalum oxides films improved by adding with iron oxides using an atmospheric pressure plasma jet (APPJ) is investigated. Precursors [tantalum ethoxide, Ta(OC2H5)5]2] and ferrocene [Fe(C5H5)2] vapors are carried by argon gas, mixed by oxygen gas and injected into air plasma torch for rapid synthesis of organo-tantalum-iron oxides (TaFexOyCz) films onto the polished stainless steel substrate at a short exposed-duration of 35 s. The APPJ-synthesized TaFexOyCz films possess the prominent Li+ ionic intercalation performance for 200 cycles of reversible Li+ ionic intercalation and deintercalation in a 1 mol/L LiClO4-propylene carbonate electrolyte by switching measurements with a potential sweep from − 1.25 to 1.25 V at a scan rate of 40 mV/s. After 200 cycles of reversible Li+ ionic intercalation and deintercalation, the Li+ ions intercalated and deintercalated charges are respectively increased from 2.41 and 1.91mC/cm2 for TaOyCz film to 5.69 and 5.23 mC/cm2 for TaFexOyCz film. The Li+ ionic conduction performance of TaOyCz film is highly enhanced from 5.76 × 10−11 to 1070 × 10−11 S/cm for TaFexOyCz film, while proven by electrochemical impedance spectroscopy in the devices of polyethylene terephthalate (PET)/indium tin oxide (ITO)/NiOx/TaOyCz/NiOx/ITO and PET/ITO/NiOx/TaFexOyCz/NiOx/ITO.