Binder‐Free Direct Ink Writing of Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 Garnet Electrolytes for All‐Solid‐State Batteries

ABSTRACT Fabricating thin, fully dense oxide ceramic electrolytes without polymer binders remains a central manufacturing bottleneck for all‐solid‐state lithium batteries (ASSBs). Conventional pressing routes yield (LLZTO) pellets exceeding 500 m in thickness, and the 15 –30 wt.% polymer binders require deposit grain‐boundary carbon during sintering, suppressing ionic conductivity by 10% –40%. Here, we demonstrate binder‐free direct ink writing (DIW) of LLZTO using a ternary ‐terpineol/ethylene glycol/ceramic capillary suspension, in which trace ethylene glycol (2 vol.%) generates a percolating pendular‐bridge network that imparts a recoverable yield stress of Pa and Pa without any polymer. The optimized 65 vol.% (85.9 wt.%) LLZTO ink exhibits pronounced shear‐thinning behavior. Sintering at 1300/4 h yields 95.8% relative density at 254 m thickness with an intrinsic bulk ionic conductivity of 17.3 and a cycle‐median bulk value of 11.8 mS , consistent with the upper range of Ta‐stabilized cubic LLZO.