Supplementary information files for "Multi-scale 3D printing of negative electrodes: A pathway to enhanced lithium-ion battery performance"

Supplementary files for article " Multi-scale 3D printing of negative electrodes: A pathway to enhanced lithium-ion battery performance"<br><br>This study introduces a multi-scale, multi-modal approach to the design and 3D printing of high-performance negative electrodes for lithium-ion batteries. Two types of printable inks were formulated using either alginate or carboxymethyl cellulose (CMC) as the primary binder, combined with styrene-butadiene rubber (SBR) and modified with a secondary fluid, 1-octanol. Rheological studies confirm that inks with secondary fluids exhibit higher viscosity and shear-thinning behaviour together with a yield stress of 20 Pa, compared to 14 Pa for non-modified formulations, enabling smooth extrusion and stable patterning in the direct ink writing (DIW) process. Cryo-SEM analysis confirmed the formation of well-aligned capillary networks that significantly reduced through-plane tortuosity from 6.3 to 4.5, enhancing ionic conductivity. Electrochemical testing revealed that 3D-printed electrodes outperformed traditional draw-down coated counterparts across multiple metrics. The dual-binder 3D-printed electrode demonstrated a 95 % discharge capacity retention at 5C, compared to 73 % for single-binder with octanol and only 19 % for alginate-based draw- down electrodes. Charge transfer resistance was reduced by over 40 % in printed structures. These results validate that ink-level and structural optimisation through a multi-scale design strategy can significantly improve battery performance, offering a viable route towards scalable, energy-dense, and high-power Li-ion technologies.<br><br>© Elsevier Ltd, All rights reserved.