Fabrication of all-solid-state lithium battery with lithium metal anode using Al 2O 3-added Li 7La 3Zr 2O 12 solid electrolyte

Abstract

Li 7La 3Zr 2O 12 (LLZ) solid electrolyte is one of the promising electrolytes for all-solid-state battery due to its high Li ion conductivity and stability against Li metal anode. However, high calcination temperature for LLZ preparation promotes formation of La 2Zr 2O 7 impurity phase. In this paper, an effect of Al 2O 3 addition as sintering additive on LLZ solid electrolyte preparation and electrochemical properties of Al 2O 3-added LLZ were examined. By the Al 2O 3 addition, sintered LLZ pellet could be obtained after 1000 °C calcination, which is 230 °C lower than that without Al 2O 3 addition. Chemical and electrochemical properties of the Al 2O 3-added LLZ, such as stability against Li metal and ion conductivity, were comparable with the LLZ without Al 2O 3 addition, i.e. σ bulk and σ total were 2.4 × 10 −4 and 1.4 × 10 −4 S cm −1 at 30 °C, respectively. All-solid-state battery with Li/Al 2O 3-added LLZ/LiCoO 2 configuration was fabricated and its electrochemical properties were tested. In cyclic voltammogram, clear redox peaks were observed, indicating that the all-solid-state battery with Li metal anode was successfully operated. The redox peaks were still observed even after one year storage of the all-solid-state battery in the Ar-filled globe-box. It can be inferred that the Al 2O 3-added LLZ electrolyte would be a promising candidate for all-solid-state battery because of facile preparation by the Al 2O 3 addition, relatively high Li ion conductivity, and good stability against Li metal and LiCoO 2 cathode.