Aqueous Processing of LiCoO₂–Li_6.6La₃Zr_1.6Ta_0.4O₁₂ Composite Cathode for High-Capacity Solid-State Lithium Batteries

To fabricate ceramic composite cathodes LiCoO2–Li6.6La3Zr1.6Ta0.4O12 (LCO-LLZTO) on an industrial scale, a water-based tape-casting process was developed, which is scalable and environmentally friendly. Additionally, the cosintering behavior of the two materials, often leading to poor electrochemical performance, was optimized via a Li2O-rich atmosphere. The resulting dense, free-standing, and phase-pure LCO-LLZTO mixed cathodes were assembled into full cells using a dual-layer solid polymer-ceramic separator and an In–Li anode. These cells show very high utilization rates for LCO of approximately 90% at a high areal capacity of over 3 mAh cm–2, demonstrating the potential of water-based tape-casting for a scalable and sustainable manufacturing of oxide-ceramic based solid-state Li batteries.