Multi-Scale 3d Printing of Negative Electrodes: A Pathway to Enhanced Lithium-Ion Battery Performance

Abstract

This study introduces a multi-scale approach to the design and 3D printing of high-performance negative electrodes for lithium-ion batteries. By formulating two distinct types of printable inks with either alginate or carboxymethyl cellulose (CMC) as the primary binder, combined with styrene-butadiene rubber (SBR) and modified with secondary fluids like 1-octanol, the work demonstrates improved control over electrode micro- and macrostructural properties. Rheological studies confirm that inks with secondary fluids exhibit higher viscosity and shear-thinning behaviour, enabling smooth extrusion and stable patterning in the direct ink writing (DIW) process. Cryo-SEM analysis reveals a well-aligned graphite-binder structure that minimises tortuosity, enhancing ionic conductivity. Electrochemical testing shows that 3D-printed electrodes outperform traditional draw-down coated counterparts, achieving 20% higher discharge capacities, superior capacity retention, and reduced internal resistance by over 40%. This research validates the efficacy of a multi-scale design methodology, from ink formulation to structural optimisation, as a promising pathway for advancing next-generation lithium-ion battery electrodes.

Keywords: 3D printing, Graphite electrode, tortuosity, rate capability