School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China.
Department of Physics and Astronomy, University of North Carolina , Chapel Hill, North Carolina 27599-3255, United States.
ACS Appl Mater Interfaces. 2017 Jan 18;9(2):1542-1552. doi: 10.1021/acsami.6b13902. Epub 2017 Jan 5.
Owing to their high conductivity, crystalline LiGaLaZrO garnets are promising electrolytes for all-solid-state lithium-ion batteries. Herein, the influence of Ga doping on the phase, lithium-ion distribution, and conductivity of LiGaLaZrO garnets is investigated, with the determined concentration and mobility of lithium ions shedding light on the origin of the high conductivity of LiGaLaZrO. When the Ga concentration exceeds 0.20 Ga per formula unit, the garnet-type material is found to assume a cubic structure, but lower Ga concentrations result in the coexistence of cubic and tetragonal phases. Most lithium within LiGaLaZrO is found to reside at the octahedral 96h site, away from the central octahedral 48g site, while the remaining lithium resides at the tetrahedral 24d site. Such kind of lithium distribution leads to high lithium-ion mobility, which is the origin of the high conductivity; the highest lithium-ion conductivity of 1.46 mS/cm at 25 °C is found to be achieved for LiGaLaZrO at x = 0.25. Additionally, there are two lithium-ion migration pathways in the LiGaLaZrO garnets: 96h-96h and 24d-96h-24d, but the lithium ions transporting through the 96h-96h pathway determine the overall conductivity.
由于其高导电性，晶态 LiGaLaZrO 石榴石是全固态锂离子电池有前途的电解质。在此，研究了 Ga 掺杂对 LiGaLaZrO 石榴石的相、锂离子分布和电导率的影响，确定的锂离子浓度和迁移率揭示了 LiGaLaZrO 高电导率的起源。当 Ga 浓度超过每个分子式单位的 0.20 Ga 时，发现石榴石型材料呈立方结构，但较低的 Ga 浓度会导致立方相和四方相共存。LiGaLaZrO 中的大部分锂位于八面体 96h 位，远离中心八面体 48g 位，而其余的锂位于四面体 24d 位。这种锂离子分布导致锂离子迁移率高，这是高电导率的起源；在 x = 0.25 时，LiGaLaZrO 的室温下锂离子电导率高达 1.46 mS/cm。此外，LiGaLaZrO 石榴石中有两种锂离子迁移途径：96h-96h 和 24d-96h-24d，但通过 96h-96h 途径传输的锂离子决定了整体电导率。
