We study ion transport limitations in composite electrodes for all-solid-state lithium batteries. These electrodes are composed of variable volume fractions of active material particles (Li₄Ti₅O₁₂) and of a sulfide-based solid electrolyte, while the volume fraction of carbon black acting as conductive additive is held constant. The ion transport limitations are characterized by impedance spectroscopic measurements on different types of symmetrical solid-state cells. Ion transport resistances are calculated either based on a transmission line model or from the Li⁺ ion current under electron-blocking conditions. In addition, we demonstrate a cell setup, for which both types of measurements can be carried out on the same composite electrodes. Effective ion transport tortuosities ${\tau }_{\text{eff}}$ are then derived from the resistance values and analyzed in dependence on the volume fraction of the solid electrolyte in the composite electrodes, $\epsilon$ . We show that for $\epsilon \ge 0.4,$ both methods yield very similar tortuosity values, while discrepancies between the results obtained from the two methods are found for $\epsilon <0.4$. Our results give strong indication that the power density of solid-state batteries with volume fractions $\epsilon$ around 0.4 of the best solid Li⁺ electrolytes should be at least equal that of commercial liquid electrolyte-based Li-ion batteries.

我们研究了全固态锂电池复合电极中的离子传输限制。这些电极由活性物质颗粒（Li ₄ Ti ₅ O ₁₂）和硫化物类固体电解质的可变体积分数组成，而用作导电添加剂的炭黑的体积分数保持恒定。离子传输限制的特征在于对不同类型的对称固态电池进行阻抗谱测量。离子传输阻力是根据传输线模型或Li ^{+来计算的}电子阻挡条件下的离子电流。此外，我们演示了一种电池设置，对于这两种类型的测量，都可以在同一复合电极上进行。有效的离子迁移曲折${\tau }_{\text{效}}$ 然后从电阻值中推导得出，并根据复合电极中固体电解质的体积分数进行分析， $\epsilon$。我们证明了$\epsilon \ge 0.4，$ 两种方法产生的曲折度值非常相似，而从两种方法获得的结果之间存在差异 $\epsilon <0.4$。我们的结果有力地表明，体积分数小的固态电池的功率密度$\epsilon$约0.4的最佳固态Li ⁺电解质应至少等于商用液体电解质基锂离子电池的电解质。