The critical factors that determine the performance and lifetime of solid-state batteries (SSBs) are driven by the electrode–electrolyte interfaces. The main challenge in fabricating all-oxide cathode composites for garnet-based SSBs has been lowering the thermal processing window in which both good contact and low interfacial resistance can be achieved. Here, we report an alternative ceramic processing strategy that enables the fabrication of all-oxide composite cathodes at an unusually low processing temperature without the use of extra sintering additives or a fluid electrolyte (polymer-gel or liquid electrolyte). We present specific examples of the most common LiFePO₄ and LiCoO₂ cathodes with a Li-garnet (Li₇La₃Zr₂O₁₂, LLZO) solid-electrolyte. We demonstrate an infiltration step to directly synthesize the LiCoO₂ cathode from metal salts in a porous LLZO scaffold, resulting in the formation of a composite cathode such as LiCoO₂–LLZO on top of a dense LLZO solid electrolyte at a low processing temperature of 700 °C. A promising discharge capacity of 118 mA h g⁻¹ (3–4.05 V) with a low interfacial resistance of 62 Ohm cm² is realized for LiCoO₂ with a lithium anode, whereas critical phase instabilities for LiFePO₄ are uncovered. Our findings encourage a move away from synthesis techniques that employ particle mixing and sintering to fabricate composites. We provide a blueprint for circumventing adverse interphase reactions according to chemistry and ceramic thermal processing budgets in the preparation of these ceramic interfaces as well as for increasing the number of reaction sites for high-performing composite cathodes for Li-garnet SSBs. In addition, the ceramic methods presented are scalable and mass manufacturable for the large-scale production of such composite cathodes for future industry.

中文翻译：

---

石榴石型固态锂电池的所有陶瓷阴极复合材料的设计和制造均朝着低界面电阻的方向发展

决定固态电池（SSB）性能和寿命的关键因素是电极-电解质界面。制造用于石榴石基SSB的全氧化物阴极复合材料的主要挑战是降低热处理窗口，在该窗口中既可以实现良好的接触又可以实现较低的界面电阻。在这里，我们报告了一种替代性的陶瓷加工策略，该策略能够在极低的加工温度下制造全氧化物复合阴极，而无需使用额外的烧结添加剂或液体电解质（聚合物凝胶或液体电解质）。我们提供了最常见的带有锂石榴石（Li ₇ La ₃ Zr _2的LiFePO ₄和LiCoO ₂阴极）的具体示例。O ₁₂，LLZO）固体电解质。我们演示了一个渗透步骤，该步骤可从多孔LLZO支架中的金属盐直接合成LiCoO ₂阴极，从而在700的低处理温度下在致密LLZO固​​体电解质上形成复合阴极，例如LiCoO ₂ -LLZO ℃。具有锂阳极的LiCoO ₂实现了有希望的放电容量118 mA hg ^-1（3–4.05 V），界面电阻低至62 Ohm cm ²，而LiFePO _4的临界相不稳定被发现。我们的发现鼓励远离使用粒子混合和烧结来制造复合材料的合成技术。我们提供了一个蓝图，用于在制备这些陶瓷界面时根据化学和陶瓷热处理预算来规避不利的相间反应，并增加锂石榴石SSB高性能复合阴极的反应位点数量。另外，提出的陶瓷方法是可规模化的并且可大规模制造以用于未来工业的这种复合阴极的大规模生产。