Direct-ink-writing of all-solid-state batteries with solvent-free, non-flammable electrolytes toward wearable electronics

초록

As demand for customized wearable electronics grows, free-form Li-ion batteries (LIBs) are attracting significant attention. Although substantial advancements have been made in printed LIBs for shape-versatile electronics, the development of printable solid-state electrolytes remains challenging due to the difficulty of simultaneously achieving desirable rheological properties and ionic conductivity. In this study, a solvent-free, non-flammable solid polymer electrolyte (SPE) is designed as a novel three-dimensional (3D) printable electrolyte via direct ink writing (DIW) for all-solid-state batteries (ASSBs). The solvent-free nature of this SPE eliminates post-annealing steps, enhancing safety by mitigating risks of leakage, short-circuiting, and fire. Additionally, precise control over polymer molecular weight and electrolyte composition enables high printing resolution (similar to 100 mu m), high ionic conductivity (0.705 mS cm(-1) at 25 degrees C), and intrinsic non-flammability. A 3D-printed ASSB, featuring a LiFePO4 cathode and Li4Ti5O12 anode with a mass loading of 7 mg cm(-2), achieves a high areal capacity of 1.14 mAh cm(-2), surpassing all previously reported directly printed ASSBs. This SPE facilitates scalable production of fully DIW-printed ASSBs with superior design flexibility and space efficiency, enabling printing onto customized targets such as flexible substrates and advancing the development of next-generation wearable electronics.

키워드