Editors: | F. Kongoli, F. Marquis, S. Kalogirou, B. Raveau, A. Tressaud, H. Kageyama, A. Varez, R. Martins. |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2022 |
Pages: | 154 pages |
ISBN: | 978-1-989820-34-6 (CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
The final prices of a LIB depend to a large extent on the materials used and the manufacturing process. The reduction of non-active materials (50% of battery weight) (Al and Cu current collectors, separators),, plays a fundamental role in reducing costs for both the production process and the final device [1]. On the other hand, the cathode thickness currently limits the total energy density and power of LIBs. One option to address this limitation is to increase the cathode thickness and consequently balancing with a thicker anode. In this way, the active materials volume ratio in the cell increases (the electrodes areal and volume capacities grow), achieving higher specific energy and specific power per weight and per volume [2].
Commercially available batteries are usually composed by cylindrical, coin, prismatic or pouch cells. Therefore, the development of new processing technologies is needed to design more complex geometries that could fit specific cell designs. In this context, additive manufacturing (AM) technologies have shown their potential for the design of 3D objects with non-conventional geometries and reduce number of produced parts and have been recently applied to different energy devices [3]. Although AM technology has not been used for commercial batteries, its use can contribute to the optimization of the final design of the devices, allowing the use of batteries with more complex shapes.
In this work, Fused Filament Fabrication (FFF) is proposed as a cheap, affordable and solvent-free processing method alternative to conventional electrode manufacturing for Li-ion batteries, which allows developing additive-free ceramic electrodes with enhanced energy density. The production of thick ceramic LiCoO2 (LCO) electrodes using a desktop 3D-printing was developed as an alternative to conventional electrode manufacturing for Li-ion batteries. Firstly, the filament formulation based on LCO powders and a sacrificial polymers blend, is optimized in order to achieve the suitable features (viscosity, flexibility and mechanical consistency) to be used in a conventional desktop 3-D printing. Printing parameters were optimized to produce defect-free bodies with coin geometry (12 mm diameter and 230-850 µm thickness). Thermal debinding and sintering were studied in order to obtain all ceramic LCO electrodes with adequate porosity. The additive-free sintered electrodes (850 µm thickness) have enhanced areal and volumetric capacities (up to 28 mA·h·cm-2 and 354 mA·h·cm-3) due to their extremely high mass loading (up to 285 mg·cm-2). Thus, the Li//LCO half-cell delivered an energy density of 1310 W·h·L-1. The ceramic nature of the electrode permits the use of a thin film of paint gold as current collector, reducing considerably the polarization of thick electrodes. Thus, the whole manufacturing process developed in this work is a complete solvent-free method to produce tuneable shape electrodes with enhanced energy density, opening the door for the manufacturing of high-density batteries with complex geometries and easily recyclable.