A full magnetron sputtering method for constructing low-impedance interfaces in all-solid-state thin-film lithium batteries

All-solid-state thin-film lithium battery (ASSTFLB) is a new type of energy device that is suitable for miniaturized intelligent terminals, while its application is largely limited by the extremely high interface impedance between the electrodes and the solid-state electrolyte. Herein, we report a full magnetron sputtering (FMS) method to significantly decrease the interface impedance. By systematically optimizing the parameters of FMS, LiCoO2 (LCO) cathode, fluorine-doped Li0.33La0.557TiO3 (F-LLTO) electrolyte, and Ti3O anode are prepared. As a result, LCO cathode shows an initial capacity of 47.1 μAh cm−2 μm−1 and a capacity retention rate of 82% after 100 cycles. Meanwhile, the internal resistance of F-LLTO electrolyte is as low as 728 Ω and the capacity retention of Ti3O anode reaches up to 100% after 200 cycles. Benefiting from the nano-compact interface and pore-free multilayer structure enabled by FMS, Ti3O|F-LLTO|LCO delivers a competitively low internal resistance of ~2600 Ω. This work provides a feasible nano-fabrication approach for high-performance solid-state micro-batteries and enriches the development of smart nano-materials for miniature electrochemical energy storage.