Solid-state electrolytes for Li-ion batteries are attracting growing interest as they allow building safer batteries, also using lithium-metal anodes. Here, we studied a compound in the lithium superionic conductor (LISICON) family, i.e., Li_4–xGe_1–xP_xO₄ (LGPO). Thin films were deposited via pulsed laser deposition, and their electrical properties were compared to those of ceramic pellets. A detailed characterization of their microstructures shows that thin films can be deposited fully crystalline at higher temperatures but also partially amorphous at room temperature. The conductivity is not strongly influenced by the presence of grain boundaries, exposure to air, or lithium deficiencies. First-principles molecular dynamics simulations were employed to calculate the lithium-ion diffusion profile and the conductivity at various temperatures of the ideal LGPO crystal. Simulations give the upper limit of conductivity for a defect-free crystal, which is in the range of 10^–2 S cm^–1 at 300 °C. The ease of thin-film fabrication and room-temperature Li-ion conductivity in the range of a few μS cm^–1 make LGPO very appealing electrolyte material for thin-film all-solid-state all-oxide microbatteries.

中文翻译：

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Li _{4– x} Ge _{1– x} P _x O ₄，一种用于全氧化物微电池的潜在固态电解质

锂离子电池用固态电解质越来越引起人们的兴趣，因为它们可以使用锂金属阳极制造更安全的电池。在这里，我们研究了锂超离子导体（LISICON）系列中的一种化合物，即Li _{4– x} Ge _{1– x} P _x O ₄（LGPO）。通过脉冲激光沉积沉积薄膜，并将其电性能与陶瓷颗粒的电性能进行比较。它们的微结构的详细表征表明，薄膜可以在较高温度下完全结晶沉积，但在室温下也可以部分非晶沉积。电导率不受晶界，暴露于空气或锂缺乏的强烈影响。第一性原理分子动力学模拟用于计算理想LGPO晶体在各种温度下的锂离子扩散曲线和电导率。仿真给出了无缺陷晶体的电导率上限，范围为10 ^–2 S cm ^–1在300°C下。薄膜制造的简易性和室温锂离子电导率在几μScm ^–1的范围内，使LGPO非常适合薄膜全固态全氧化物微电池的电解质材料。