Sintering of Li-garnets: Impact of Al-incorporation and powder-bed composition on microstructure and ionic conductivity
Sandra Lobe,
Alexander Bauer,
Doris Sebold,
Nadine Wettengl,
Dina Fattakhova-Rohlfing,
Sven Uhlenbruck
Affiliations
Sandra Lobe
Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-1), Materials Synthesis and Processing, 52425, Jülich, Germany; Corresponding author.
Alexander Bauer
Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-1), Materials Synthesis and Processing, 52425, Jülich, Germany
Doris Sebold
Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-1), Materials Synthesis and Processing, 52425, Jülich, Germany
Nadine Wettengl
Forschungszentrum Jülich GmbH, Central Institute for Engineering, Electronics and Analytics (ZEA-3), Analytics, 52425, Jülich, Germany
Dina Fattakhova-Rohlfing
Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-1), Materials Synthesis and Processing, 52425, Jülich, Germany; Helmholtz-Institute Münster, Ionics in Energy Storage (IEK-12), 52425, Jülich, Germany; Faculty of Engineering and Center for Nanointegration Duisburg-Essen (CENIDE), Universität Duisburg-Essen, Lotharstraße 1, 47057, Duisburg, Germany
Sven Uhlenbruck
Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-1), Materials Synthesis and Processing, 52425, Jülich, Germany; Helmholtz-Institute Münster, Ionics in Energy Storage (IEK-12), 52425, Jülich, Germany
Garnet-structured Li-ion conductors are promising candidates as electrolytes for all-solid-state batteries. However, sintering of these materials is still a challenge, due to Li-loss accompanied by decomposition at elevated temperatures. In this study, Li5La3Ta2O12, a garnet material with reduced Li-content, was used as a model material to investigate the impact of the Li content in powder beds as well as the presence of Al either in the green bodies or in the powder beds on the properties of the resulting sintered materials. The resulting relative densities were increased by sintering in a Li-rich powder bed compared to a powder bed with identical stoichiometry. Furthermore, Al either in the source material or in the powder bed was shown to support densification, even if it is not incorporated in the structure. The highest ionic conductivity was 3.4 × 10-5 S cm-1 at 30 °C for Li5La3Ta2O12, which was sintered in a Li6.54Al0.02La3Zr1.6Ta0.4O12 powder bed.
