On the Road to a Multi-Coaxial-Cable Battery: Development of a Novel 3D-Printed Composite Solid Electrolyte

Abstract

The high areal-energy and power requirements of advanced microelectronic devices favor the choice of a lithium-ion system, since it provides the highest energy density of available battery technologies suitable for a variety of applications. Several attempts have been made to produce primary and secondary thin-film batteries utilizing printing techniques. These technologies are still at an early stage, and most currently-printed batteries exploit printed electrodes sandwiching self-standing commercial polymer membranes, produced by conventional extrusion or papermaking techniques, followed by soaking in non-aqueous liquid electrolytes. In this work, we suggest a novel flexible-battery design and report the initial results of development and characterization of novel 3D printed allsolid-state electrolytes prepared by fused-filament fabrication (FFF). The electrolytes are composed of LiTFSI, polyethylene oxide (PEO), which is a known lithium-ion conductor, and polylactic acid (PLA) for enhanced mechanical properties and high-temperature durability. The 3D printed electrolytes were characterized by means of ESEM imaging, mass spectroscopy, differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS). TOFSIMS analysis reveals formation of lithium complexes with both polymers. The flexible all-solid LiTFSI-based electrolyte exhibited bulk ionic conductivity of 3 × 10 −5 S/cm at 90°C and 156ohmxcm 2 resistance of the solid electrolyte interphase (SEI). We believe that the coordination mechanism of the lithium cation by the oxygen of the PLA chain is similar to that of PEO and local relaxation motions of PLA chain segments could promote Li-ion hopping between oxygens of adjacent CH-O groups. What is meant by this is that PLA not only improves the mechanical properties of PEO, but also serves as a Li-ion-conducting medium. These results pave the way for a fully printed solid battery, which enables free-form-factor flexible geometries.

How to Pack a Punch – Why 3D Batteries are Essential

“…The LFP/LTO full cell of 8×8 mm 2 footprint exhibited a discharge capacity of 102 mAh.g −1 at 0.2 C after 35 cycles [66,68] . The printed 3D LIMB displayed a high areal‐energy density of 9.7 J.cm −2 at a power density of 2.7 mW.cm −2 , which demonstrates the capability of 3D printing to construct high‐aspect structures within a small area [69,70] …”

“…[66,68] The printed 3D LIMB displayed a high areal-energy density of 9.7 J.cm À 2 at a power density of 2.7 mW.cm À 2 , which demonstrates the capability of 3D printing to construct high-aspect structures within a small area. [69,70] While interweaving electrode network and multicoaxialcable battery designs have been recently proposed, [25,71] the main use of FDM is for the fabrication of planar electrodes for LIBs. Extensive efforts have been made to increase the proportion of active materials in FDM-printed electrodes.…”

Ag-Coated Cu/Polylactic Acid Composite Filament for Lithium and Sodium-Ion Battery Current Collector Three-Dimensional Printing via Thermoplastic Material Extrusion

“…Based on the work reported by Ragones et al (Ragones et al, 2019), the percentage of crystallinity of the polymer matrix was calculated using Eq. (4):…”

“…Starting from 2017, various groups initiated the development of bespoke composite 3D printable filaments, specifically developed to print components of a classical LIB: positive electrodes (PLA/LiFePO 4 (Ragones et al, 2018;Maurel et al, 2019), PP/LiFePO 4 (Maurel et al, 2020), PLA/LMO (Reyes et al, 2018)), negative electrodes (PLA/graphite (Maurel et al, 2018;Maurel et al, 2019), PLA/LTO (Ragones et al, 2018;Reyes et al, 2018)), separator (PLA/SiO 2 (Maurel et al, 2019)) and solid polymer electrolyte (PEO/LiTFSI (Maurel et al, 2020a), PLA/ PEO/LiTFSI (Ragones et al, 2019)). In 2018, an important milestone was reached in the field as our group (Maurel et al, 2018) reporting for the first time that the introduction of a thoroughly chosen plasticizer helps to increase the number of charges within the composite filament considerably.…”

New Promises and Opportunities in 3D Printable Inks Based on Coordination Compounds for the Creation of Objects with Multiple Applications

“…For each deposited material layer, the direction of material deposition can be changed. This allows uniform scaffolds to be obtained with controllable pore morphology, and pore interconnectivity can be completed by changing the spacing between the paths of the material and the direction of material deposition for consecutively deposited layers [8, 9] . The method does not require any solvent and offers great ease and flexibility in material handling and processing.…”