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Abstract Additive manufacturing, also called 3D printing, has the potential to enable the development of flexible, wearable and customizable batteries of any shape, maximizing energy storage while also reducing dead-weight and volume. In this work, for the first time, three-dimensional complex electrode structures of high-energy density LiNi1/3Mn1/3Co1/3O2 (NMC 111) material are developed by means of a vat photopolymerization (VPP) process combined with an innovative precursor approach. This innovative approach involves the solubilization of metal precursor salts into a UV-photopolymerizable resin, so that detrimental light scattering and increased viscosity are minimized, followed by the in-situ synthesis of NMC 111 during thermal post-processing of the printed item. The absence of solid particles within the initial resin allows the production of smaller printed features that are crucial for 3D battery design. The formulation of the UV-photopolymerizable composite resin and 3D printing of complex structures, followed by an optimization of the thermal post-processing yielding NMC 111 is thoroughly described in this study. Based on these results, this work addresses one of the key aspects for 3D printed batteries via a precursor approach: the need for a compromise between electrochemical and mechanical performance in order to obtain fully functional 3D printed electrodes. In addition, it discusses the gaps that limit the multi-material 3D printing of batteries via the VPP process.

High-resolution additive manufacturing offers access to the production of intricate architectures with small features that can revolutionize the fabrication of next-generation batteries. Relegated to two-dimensional sheets, commercial lithium-ion batteries consist of stacked leaflets, which are manufactured in restricted stacked or rolled geometries. By leveraging the most recent advancements of vat photopolymerization (VPP), the next-generation of shape-conformable three-dimensional batteries can be co-designed with known application requirements and provide enhanced safety and power performance based on reduced weight and dead volume. Herein, an overview of the state of the art with perspectives towards the development of electroactive photo-polymerizable resins for the direct fabrication of complete multi-material three-dimensional batteries is presented. Different approaches are described, including the formulation of composite resin through the introduction of solid electroactive particles, soluble components or metal precursors. Finally, the impact of the thermal post-processing steps on the resulting electrochemical properties of the VPP printed battery component or device is thoroughly discussed. This study paves the way towards the manufacturing of a complete high-resolution shape conformable 3D battery via VPP with enhanced power density.

This article focuses on the development of polylactic acid– (PLA-) based thermoplastic composite filament for its use, once 3D printed via thermoplastic material extrusion (TME), as current collector at the negative electrode side of a lithium-ion battery or sodium-ion battery. High electronic conductivity is achieved through the introduction of Ag-coated Cu charges, while appropriate mechanical performance to allow printability was maintained through the incorporation of poly(ethylene glycol) dimethyl ether average Mn ∼ 500 (PEGDME500) as a plasticizer into the PLA polymer matrix. Herein, thermal, electrical, morphological, electrochemical, and printability characteristics are discussed thoroughly. While Ag-Li alloy formation is reported at 0.1V upon cycling, its use with active materials such as Li4Ti5O12 (LTO) or Li2-terephthalate (Li2TP) operating at a plateau at higher potential is demonstrated. Furthermore, its ability to be used with negative electrode active material of sodium-ion battery technology in a wide potential window is demonstrated.

The external seed coat cell layer of certain species is specialized in the production and extrusion of a polysaccharide matrix called mucilage. Variations in the content of the released mucilage have been mainly associated with genetically regulated physiological modifications. Understanding the mucilage extrusion process in crop species is of importance to gain deeper insight into the complex cell wall biosynthesis and dynamics. In this study, we took advantage of the varying polysaccharide composition and the size of the flax mucilage secretory cells (MSCs) to study mucilage composition and extrusion in this species of agricultural interest. We demonstrate herein that flax MSCs are structured in four superimposed layers and that rhamnogalacturonans I (RG I) are firstly synthesized, in the upper face, preceding arabinoxylan and glucan synthesis in MSC lower layers. Our results also reveal that the flax mucilage release originates from inside MSC, between the upper and deeper layers, the latter collaborating to trigger polysaccharide expansion, radial cell wall breaking and mucilage extrusion in a peeling fashion. Here, we provide evidence that the layer organization and polysaccharide composition of the MSCs regulate the mucilage release efficiency like a peeling mechanism. Finally, we propose that flax MSCs may represent an excellent model for further investigations of mucilage biosynthesis and its release.

3D printing of energy storage systems is at the heart of In-Space Manufacturing strategy. Within this context, Li-ion polymer batteries printing through Fused Filament Fabrication (FFF) is envisaged. This study is devoted to optimising the extruded solid polymer electrolyte filament properties. As the poly(ethylene oxide) (PEO) – lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte offers the best Li+ conductivities but suffers from poor mechanical behaviour, poly(propylene) (PP) is added to ensure filament printability. An exhaustive investigation highlights the impact of the PEO molar weight and the LiTFSI and PP proportions. Fine-tuning these parameters alters molten phase viscosity, which affects the electrolyte morphology and ionic conductivity. Best formulations feature a co-continuous structure that provides effective mechanical reinforcement and exhibits the best ionic conductivity reported so far for an FFF-printed solvent-free polymer electrolyte of 1.2 × 10−4 S.cm−1 at 70°C. Therefore, it opens the way towards polymer battery printing, on the Earth and in microgravity conditions.

A new chapter of space exploration is opening with future long-duration space missions toward the Moon and Mars. In this context, the European Space Agency is developing out-of-the-earth manufacturing abilities, to overcome the absence of regular supplies for astronauts’ vital needs (food, health, housing, energy). Additive manufacturing is at the heart of this evolution because it allows the fabrication of tailorable and complex shapes, with a considerable ease of process. Fused filament fabrication (FFF), the most generalized 3D printing technique, has been integrated into the International Space Station to produce polymer parts in microgravity. Filament deposition printing has also a key role to play in Li-ion battery (LIB) manufacturing. Indeed, it could reduce manufacturing cost & time, through one-shot printing of LIB, and improve battery performances with suitable 3D architectures. Thus, additive manufacturing via FFF of LIB in microgravity would open the way to in-space manufacturing of energy storage devices. However, as liquid and volatile species are not compatible with a space station-confined environment, solvent-free 3D printing of polymer electrolytes (PEs) is a necessary step to make battery printing in microgravity feasible. This is a challenging stage because of a strong opposition between the mechanical requirements of the feeding filament and electrochemical properties. Nowadays, PE manufacturing remains a hot topic and lots of strategies are currently being studied to overcome their poor ionic conductivity at room temperature. This work firstly gives a state of the art on the 3D printing of LIBs by FFF. Then, a summary of ionic conduction mechanisms in PEs permits to understand the several strategies studied to enhance PEs performances. Thanks to the confrontation with the specifications of FFF printing and the microgravity environment, polymer blends and composite electrolytes turn out to be the most suitable strategies to 3D print a lithium-ion polymer battery in microgravity.

Flax (Linum usitatissimum L.) seed oil, which accumulates in the embryo, and mucilage, which is synthesized in the seed coat, are of great economic importance for food, pharmaceutical as well as chemical industries. Theories on the link between oil and mucilage production in seeds consist in the spatio-temporal competition of both compounds for photosynthates during the very early stages of seed development. In this study, we demonstrate a positive relationship between seed oil production and seed coat mucilage extrusion in the agronomic model, flax. Three recombinant inbred lines were selected for low, medium and high mucilage and seed oil contents. Metabolite and transcript profiling (1H NMR and DNA oligo-microarrays) was performed on the seeds during seed development. These analyses showed main changes in the seed coat transcriptome during the mid-phase of seed development (25 Days Post-Anthesis), once the mucilage biosynthesis and modification processes are thought to be finished. These transcriptome changes comprised genes that are putatively involved in mucilage chemical modification and oil synthesis, as well as gibberellic acid (GA) metabolism. The results of this integrative biology approach suggest that transcriptional regulations of seed oil and fatty acid (FA) metabolism could occur in the seed coat during the mid-stage of seed development, once the seed coat carbon supplies have been used for mucilage biosynthesis and mechanochemical properties of the mucilage secretory cells.