A Li-free inverted-stack all-solid-state thin film battery using crystalline cathode material

Abstract Lithium metal is a potential anode material to develop all-solid-state battery (SSB) with high energy density. However, Li metal easily reacts with atmospheric component (H 2 O, CO 2 , O 2 , N 2 ) and then Li metal must be treated sensitively for industrial applications. Here, we report an inverted-stack Li-free thin-film SSB, SUS/Pt/LiPON/LiCoO 2 /Au, where highly-crystalline LiCoO 2 thin film is formed on amorphous LiPON thin film at room temperature by aerosol deposition and Li metal is electrochemically grown between SUS/Pt and LiPON. The resultant Li-free thin-film SSB operates at 4 V and repeats stable charge-discharge reactions for over 100 cycles at 25 °C.