There are a few methods to introduce residual stresses, which is also known to increase the fracture resistance, depending on the type of stress introduced into a material. In metallurgy residual stresses are introduced during plastic deformation of the material, which is known as work hardening, if it occurs heterogeneously throughout the material. Work hardening can be used to significantly increase the hardness of the substrate by increasing the defect density in the material. It can in principle be applied to any crystalline material, though it depends on the ductility. While metals can be deformed to introduce stresses, the same approach would shatter brittle ceramics, which LLZO counts as. This disallows the use of large scale plastic deformation like cold rolling and special care has to be taken when introducing residual stresses using methods, such as shot peening, Laser shock peening or sand blasting in order to keep the material intact. Other possible methods include strengthening via grain boundaries, transformation hardening, second phase hardening and solid solution strengthening. To achieve a solid solution in a ceramic, a proven method from the semiconductor industry can be used to introduce foreign ions into the matrix, ion implantation. Previous research on different ceramics, such as MgO, Al2O3, and SiC has shown that an ion-implanted material can exhibit a higher fracture toughness. The implantation of ions has a multitude of effects on the material properties, depending on the used parameters. With a high enough dose of the implanted ions or beam power, the collisions of the ions with the lattice can destabilize it, leaving behind an amorphous layer in its wake. Both of those parameters also determine the penetration depth than can be reached. This amorphized layer can even be mechanically weaker than the starting material. The conductive properties of the material can also be influenced due to the implantation. Implanted ions can create additional states in the band structure changing the electronic conductivity, which made semiconductor applications possible and is the main reason for its use. If the material is amorphized, pathways for ionic conduction can be diminished, which for battery applications is rather detrimental. Nevertheless, amorphous LLZO in thin film batteries has already been reported to reach reasonably high current densities (3.2 mA cm -²) without dendrite growth. There the thinness of the layer (70 nm) overcomes the diminished ionic conductivity of 4 orders of magnitude compared to bulk crystalline LLZO. In the semiconductor industry annealing processes are typically used to regain the crystallinity and to benefit only from the increased electronic conduction without having to worry about an inhomogeneous distribution in the amorphous structure. Parameters to achieve a similar reconstruction of the lattice, known as recrystallization, while keeping ion migration low, are not known yet in literature for solid electrolytes in general and LLZO specifically.