Chen Dequan, Zhang Gong, Xue Yongping, Xie Tingting, Zhao Ziheng, Ai Changchun*.; Synthesis of Li3+xP1-xGexS4-2xO2x electrolyte materials with high ionic conductivity and air stability by doping of GeO2 for all-solid-state lithium batteries. Ionics, 30(8), 4519-4530. (SCI, 四区/Q4, IF=2.4)
Abstract
Sulfide-based materials were widely investigated as electrolytes for all-solid-state lithium batteries owing to their good ionic conductivity and safety. However, their applications are hindered by the air sensitivity and Limited ionic conductivity. Here, a series of GeO2-doped Li3+xP1-xGexS4-2xO2x（x = 0, 0.02, 0.04, 0.06, 0.08）solid electrolytes were synthesized through a modified solid-state method and characterized comprehensively. The lithium ionic conductivity of Li3.04P0.96Ge0.04S3.92O0.08 solid electrolytes reached 3.54 mS cm-1 at room temperature and the H2S emission was only 0.31 cm-3 g when the electrolytes were exposed to air for 300 min. Importantly, the critical current density of Li3.04P0.96Ge0.04S3.92O0.08 electrolytes was 1.2 mA cm-2, which was twice of Li3PS4. In addition, the ASSLB of LiCoO2@SSEs/Li3.04P0.96Ge0.04S3.92O0.08/Li delivered an initial discharge capacity of 126.9 mAh g-1 at 0.1 C at room temperature, and it showed excellent rate performance, e.g., 126, 103, 55, 39, mAh g-1 at 0.1, 0.2, 0.5, and 1 C at RT. The cell achieved a reversible capacity of 84 mAh g-1 when the current reverted to 0.3 C. The electrochemical performance and chemical stability of Li3PS4 were improved by co-doping of Ge and O, and provided a promising approach to achieve excellent chemical and electrochemical stability for the large-scale application of sulfide-based solid state electrolytes.
硫化物基材料由于其良好的离子电导率和安全性而被广泛研究作为全固态锂电池的电解质。然而，它们的应用受到对空气敏感和离子电导率有限的阻碍。在此，通过改进的固态方法合成了一系列 GeO₂掺杂的 Li3+xP1-xGexS4-2xO2x（x = 0、0.02、0.04、0.06、0.08）固体电解质，并进行了全面表征。Li3.04P0.96Ge0.04S3.92O0.08固体电解质在室温下的锂离子电导率达到 3.54 mS cm⁻¹，并且当电解质暴露在空气中 300 分钟时，H₂S 释放量仅为 0.31 cm³/g。重要的是，Li3.04P0.96Ge0.04S3.92O0.08电解质的临界电流密度为 1.2 mA cm⁻²，是 Li₃PS₄ 的两倍。此外，LiCoO₂@SSEs/Li₃.₀₄P₀.₉₆Ge₀.₀₄S₃.₉₂O₀.₀₈/Li 的全固态锂电池在室温下以 0.1 C 放电时初始放电容量为 126.9 mAh g⁻¹，并且表现出优异的倍率性能，例如在室温下以 0.1、0.2、0.5 和 1 C 时分别为 126、103、55、39 mAh g⁻¹。当电流恢复到 0.3 C 时，电池实现了 84 mAh g⁻¹ 的可逆容量。本团队通过 Ge 和 O 的共掺杂改善了 Li3PS4的电化学性能和化学稳定性，为实现硫化物基固态电解质的大规模应用提供了一种有前途的方法，以获得优异的化学和电化学稳定性。
