Effects of Gallium Doping in Garnet-Type Li₇La₃Zr₂O₁₂ Solid Electrolytes

Abstract

High Resolution Image Download MS PowerPoint Slide Garnet-type Li 7 La 3 Zr 2 O 12 (LLZrO) is a candidate solid electrolyte material that is now being intensively optimized for application in commercially competitive solid state Li + ion batteries. In this study we investigate, by force-field-based simulations, the effects of Ga 3+ doping in LLZrO. We confirm the stabilizing effect of Ga 3+ on the cubic phase. We also determine that Ga 3+ addition does not lead to any appreciable structural distortion. Li site connectivity is not significantly deteriorated by the Ga 3+ addition (>90% connectivity retained up to x = 0.30 in Li 7–3 x Ga x La 3 Zr 2 O 12 ). Interestingly, two compositional regions are predicted for bulk Li + ion conductivity in the cubic phase: (i) a decreasing trend for 0 ≤ x ≤ 0.10 and (ii) a relatively flat trend for 0.10 < x ≤ 0.30. This conductivity behavior is explained by combining analyses using percolation theory, van Hove space time correlation, the radial distribution function, and trajectory density.