Overview on Lithium-Ion Battery 3D-Printing By Means of Material Extrusion
Authors: Maurel Alexis , Grugeon Sylvie , Armand Michel , Fleutot Benoit , Courty Matthieu , Prashantha Kalappa , Davoisne Carine , Tortajada Hugues , Panier Stéphane , Dupont Loic 
Published: December 2020

In parallel with the considerable investigations on renewable energy sources, electrical energy storage systems used to store the energy produced now and to provide it when needed have received much attention lately.1 Amongst them, lithium-ion batteries (LIB) are today the most employed in a huge range of purposes including cellphones, laptops or even electric vehicles. Current LIB consists in a planar arrangement (2D) in which the different parts of the battery (positive and negative electrodes, separator, current collectors) are rolled or stacked. Unfortunately, in this type of 2D configuration, lithium ions diffuse only along one dimension. Additive manufacturing (AM) technologies, also called 3D-printing processes, could enable the production of much more complex 3D architectures thus allowing diffusion of the lithium cations towards two or three-dimensions. Advantage of those 3D designs is that the electrochemical active surface area is expected to increase as well as the battery specific capacity and power.2 On the other hand, AM could also allow the direct incorporation of LIB within the final object, thus enabling the possibility to maximize the energy storage capabilities while reducing the dead volume and weight.
Amongst the various AM available technologies, we focused our work on the Fused Deposition Modeling (FDM) process using a thermoplastic filament as material source for the 3D-printer. In this presentation, the formulation of composite PLA-based filaments specially designed to print each parts of the LIB (with liquid electrolyte) will be described.3,4 The active material composition within the negative and positive electrodes (graphite and lithium iron phosphate (LiFePO4) respectively), was increased as high as possible in order to enhance the electrochemical performances. Furthermore, the addition of a plasticizer was required to maintain enough mechanical strength while, in the meantime, carbon black was added to confer adequate electrical properties. The impact of ceramic additives on ionic conductivity in the separator was also investigated. From the optimized filaments compositions, stepwise and then “one-shot” 3D-printing of complete LiFePO4/graphite battery cells of any shapes were carried out (Figure 1). In order to prevent short-circuits, classical 3D-printing parameters such as the infill patterns and infill density were investigated for the LIB separator improvement.
Finally, this presentation will introduce our latest results5 regarding the printability of a polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) filament (2.18 × 10−3 S cm−1 at 90 °C) optimized to be used as solid polymer electrolyte in a lithium-ion battery.
This presentation, by combining both battery and 3D-printing understandings, will tackle various electrochemical (thickness, electronic and ionic conductivity, liquid electrolyte uptake) and 3D-printing parameters (infill density, infill pattern, perimeters, over and under-extrusion, retraction), which clearly paves the way for enhanced 3D-printed LIB.

References:

[1] Tarascon, J. M. & Armand, M. Issues and challenges facing rechargeable lithium batteries. Nature
414, 359-367, doi:10.1038/35104644 (2001).
[2] Long, J. W., Dunn, B., Rolison, D. R. & White, H. S. Three-dimensional battery architectures. Chemical Reviews
104, 4463-4492, doi:10.1021/cr020740l (2004).
[3] Maurel, A. et al. Highly Loaded Graphite-Polylactic Acid Composite-Based Filaments for Lithium-Ion Battery Three-Dimensional Printing. Chemistry of Materials
30, 7484-7493, doi:10.1021/acs.chemmater.8b02062 (2018).
[4] Maurel, A. et al. Three-Dimensional Printing of a LiFePO4/Graphite Battery Cell via Fused Deposition Modeling. Scientific Reports
9, 18031, doi:10.1038/s41598-019-54518-y (2019).
[5] Maurel, A. et al. Poly(Ethylene Oxide)−LiTFSI Solid Polymer Electrolyte Filaments for Fused Deposition Modeling Three-Dimensional Printing. Journal of The Electrochemical Society
167, 070536, doi:10.1149/1945-7111/ab7c38 (2020).

Figure 1