Intermediate‐Stage Sintered LLZO Scaffolds for Li‐Garnet Solid‐State Batteries

Abstract While significant progress has been achieved in the field of Li‐garnet solid‐state batteries, their further development, is hindered by the formation of cavities at the Li 7 La 3 Zr 2 O 12 (LLZO)/Li interface at practically relevant current densities and areal capacities exceeding 1 mA cm −2 and 1 mAh cm −2 . As a result, the cells exhibit limited cycling stability due to the inhomogeneous distribution of the applied current density, and therefore, the formation of Li dendrites. Another aspect of high importance is associated with the development of the fabrication methodology of thin LLZO electrolytes for achieving the high energy density of Li‐garnet solid‐state batteries. To contribute to these two challenging problems, in this work, a facile intermediate‐stage sintering method of 50‐µm thin and porous LLZO membranes with a mean pore size of 2.5 µm is presented. The employment of such porous LLZO membranes not only provides an effective means of mitigating the formation of voids at the LLZO/Li interface due to the increased LLZO/Li surface area, but also maximizes achievable energy densities. It is demonstrated that fabricated porous LLZO membranes exhibit long cycling stability of over 1480 h at a current density of 0.5 mA cm −2 .