context: In summary, the mechanism of Li dendrite formation in LLZTO was discussed in terms of energy band structure as well as defect states, and was investigated by REELS, SPEM, and Nano Q-DLTS. The experimental results corroborate that the higher defect densities at the GBs lower the SBH by 0.5 eV and makes metallic Li atoms propagate along the GBs in LLZTO. As a way of preventing Li dendrite formation in LLZTO, bandgap engineering by the laser annealing treatment was proposed. Amorphous LLZTO and Li2O2 layers formed after laser annealing hinder the Li dendrite formation by blocking the electron injection. The hybrid electrolyte cell comprising the laser-treated LLZTO sample exhibits significant improvement in cycling performance and stability. Consequently, the laser annealing treatment on the LLZTO electrolytes can direct the development of materials engineering toward high-performance solid-state batteries. Furthermore, the analytical approach in this study highlights the importance of the electronic band structure of LLZTO for its stability and provides the direction to study various solid electrolyte materials.
answer: LLZTO 