Micro-Architected Lithium Cobalt Oxide.

Advancements in additive manufacturing (AM) enable the precise engineering of micro-architected electrodes with enhanced electrochemical and mechanical properties. Existing AM approaches for fabricating lithium-ion battery cathodes rely on extrusion-based direct ink-writing, which is usually limited to 150-200 µm resolution, or vat photopolymerization (VP) 3D printing with metal salt solution, which is limited in material choices due to the complicated photoresin design and printing parameter optimization. A gel infusion AM technique is introduced to fabricate micro-architected cathodes, using lithium cobalt oxide (LCO) as a model prototype, which utilizes VP 3D printing with a "blank" photoresin to circumvent these limitations. The synthesized micro-architected LCO electrodes are free-standing and binder-free, with beam diameters below 50 µm and tunable microstructure and mechanical resilience. The nanoindentation modulus of differently oriented LCO grains varies between 148.4 and 286.6 GPa, with no grain boundary weakening. This electrode gives a reversible capacity of 122-142 mAh g-1 (11.3-13.2 mAh cm-2) up to a current density of 28 mA g-1 (2.6 mA cm-2). This method is adaptable for a broad range of cathode materials, which opens a promising pathway to fabricate micro-architected electrodes with fully controllable form factors, versatile material choices, and micro-sized resolution for future energy storage solutions.