Functionalized Magnetic 3D Printing of High Performance Electrodes for Lithium Battery

Abstract

With the trend for rapid prototyping of parts and systems, additive manufacturing process like three-dimensional (3D) printing can advance the fabrication of shape-specific architectures for anisotropic permanent magnets involving expensive and critical rare-earth elements1,2. Although in-situ alignment will open new horizons for manufacturing of complex permanent magnets, integration of alignment systems into 3D printing processes is still a challenge. In our former works, we have demonstrated a mechanism to address this challenge accomplished by integration of bonded magnet production, 3D printing, finite element modeling and system development3.Alignment of electrode pores, (e.g. using magnetic field) allow from better electrochemical transport of electrolyte through the electrode, thereby improving cell performance. The formerly developed magnetic field alignment model for 3D printed material in my postdoctoral program will be modified and used to predict the degree-of-alignment in electrodes for lithium-ion battery. The relationship between pore tortuosity and degree-of-alignment was modeled using a power law with the effect of exponent compared in Fig. 1a.A coupled electrochemical-thermal-mechanical modeled is developed to predict the cell capacity loss due to above-mentioned anodic degradation mechanisms. Keeping the porosity, the tortuosity is altered between aligned and non-aligned states, to evaluate the electrochemical transport properties like diffusivity and ionic conductivity in the electrode. The model predicts an increase in cell capacity for lower tortuosity (aligned) electrodes, which is further amplified at faster charging conditions (Fig. 1b). It is generally observed that fast charging induces a steep non-uniform charge distribution in the unaligned electrodes. With increase in alignment, the electrolyte has easier pathways leading to a more uniform charge distribution and therefore a larger capacity. An immediate impact of a more uniform charge distribution is the lowering of tendency for lithium-ions to deposit in metallic form on the anode (called lithium plating).These results provide an indication that alignment of electrodes will be beneficial towards designing a higher capacity and faster charging battery. Experimental validations are the next step towards validating the model predictions. Huber, C. et al. 3D print of polymer bonded rare-earth magnets, and 3D magnetic field scanning with an end-user 3D printer. Appl. Phys. Lett. 109, 162401 (2016).Li, L., Post, B., Kunc, V., Elliott, A. M. & Paranthaman, M. P. Additive manufacturing of near-net-shape bonded magnets: Prospects and challenges. Scr. Mater. (2017) doi:10.1016/j.scriptamat.2016.12.035.Sarkar, A. et al. Functionalizing magnet additive manufacturing with in-situ magnetic field source. Addit. Manuf. 34, 101289 (2020). Figure 1