Characterization of all-solid-state thin-film batteries with V2O5 thin-film cathodes using ex situ and in situ processes

An all-solid-state thin-film battery with a full cell structure of Li/LiPON /V2O5 /Pt has been fabricated. The structural and electrochemical propertie s of a thin-film battery fabricated by an irt situ and an ex situ process w ere compared. in the in situ process, LiPON (lithium phosphorus oxynitride) electrolyte thin film was deposited on the V2O5 thin film by radio frequen cy reactive sputtering at room temperature without breaking vacuum. After d eposition of the amorphous LIPON, a thermal evaporator in a dry room grew L i metal film as an anode. According to the results of the ac impedance anal ysis after 500 discharge cycle tests, R-i and E-ct of a thin-film battery f abricated by the ex situ process are over ten times higher than those of th e thin-film battery fabricated by the in situ process. The thin-film batter y fabricated by the ex situ process showed high capacity reduction because of the high R-i and R-ct. This result indicated that the cyclability of the thin-film battery strongly depends on the interfacial stability between th e solid electrolyte and the cathode during intercalation and deintercalatio n of Li ions. Therefore, the iii situ process holds promise for the high pe rformance of all-solid-state thin-film batteries. (C) 2001 The Electrochemi cal Society. All lights reserved.