Zro2 nano powder

To synthesize garnet-type solid electrolyte Li_6.25Al_0.25La₃Zr₂O₁₂ (LLZO) Li₂CO₃ (>99.0%, Sigma-Aldrich), La(OH)₃ (99.9%, Sigma-Aldrich), Al₂O₃ (99.8%, abcr), and ZrO₂ nano-powder (<100 nm, Sigma-Aldrich) were mixed in a stoichiometric ratio. This mixture was then ball-milled for 12 h at 350 rpm under pure oxygen atmosphere. After milling, the homogenized powder was pressed into large pellets in MgO-crucibles and then calcined at 1000 °C for 4 h under a 150-sccm oxygen flow. After ball-milling again for 20 h at 350 rpm, small pellets with diameters of ~8.3 mm and thicknesses of 2 mm were isostatically pressed with 380 MPa and sintered at 1230 °C in MgO-crucibles with mother powder (calcined LLZO powder) under oxygen flow. The LLZO pellets have a porosity of ~(94 ± 2)%, their ionic conductivity is (4.6 ± 0.4)10⁻⁴ S cm⁻¹. The ionic conductivity is calculated by considering the thickness, the contact area with the electrode, and the total bulk and grain boundaries resistance of the LLZO pellet in a Li|LLZO|Li symmetric cell extracted by fitting of electrochemical impedance result which is acquired in at 25 °C (supplementary Fig. 2). The sintered LLZO was characterized with x-ray diffraction by using a PANalytical Empyrean powder diffractometer in Bragg-Brentano θ-θ geometry with copper K_α radiation.

PMMA temporary resin acrylic (Bosworth, Trim Plus; Bosworth Company, USA), TiO₂ (nanopowder, 21 nm, ≥99.5% trace metals basis; Sigma Aldrich, Germany), ZrO₂ nanopowder (<100 nm particle size, Sigma Aldrich, China). The various test groups along with composition are given in Table 1.