Electrochemical properties of an all-solid-state lithium-ion battery with an in-situ formed electrode material grown from a lithium conductive glass ceramics sheet

A lithium insertion reaction in a Li⁺ conductive glass ceramics solid electrolyte (lithium aluminum titanium phosphate: LATP) sheet produces an in-situ formed electrode active material, which operates at 2.35 V vs. Li/Li⁺ in the vicinity of the LATP-sheet/current-collector interface. Electron energy loss spectroscopy clarifies that titanium in the LATP sheet in the vicinity of the current collector/LATP-sheet interface is preferentially reduced by this lithium insertion reaction. Charge transfer resistance between the in-situ-formed-electrode and the LATP-sheet is less than 100 Ω cm ², which is smaller than that of the common LiPON/LiCoO₂ interface. A thin film of LiCoO₂ is deposited on one side of the LATP-sheet as a Li⁺ source for developing the in-situ formed electrode material. Eventually, a Pt/LATP-sheet/LiCoO₂/Au multilayer is fabricated. The multilayer structure successfully works as an all-solid-state lithium-ion battery operating at 1.5 V. A redox peak of the battery is observed even at 100 mV s^-1 in the potential sweep curve. Additionally, charge-discharge reactions are repeated stably even after 25 cycles.