This study focuses on developing solvent-free polymer electrolytes for solid-state lithium-ion batteries intended to replace conventional liquid systems. The materials consist of a polysulfone (PSU) backbone chemically bonded to pendant polyetheramine (Jeffamine®) chains and lithium salt. The synthesis consists of four key steps: sulfonation of PSU to obtain PSU-SO3Na (40% and 60% sulfonation), conversion of these groups into sulfonyl chlorides (PSU-SO2Cl), nucleophilic substitution with Jeffamine® M − 2070 to form PSU-Jeff copolymers (40% and 60%), and finally incorporation of LiTFSI as the conducting salt to produce PSU-Jeff-LiTFSI with an O/Li ratio of 20. The conducting copolymers obtained in this way do not require solvents for their use as electrolytes, and their semi-solid gel-like appearance facilitates effective contact with the electrodes. Structural and morphological analyses were performed using 1H NMR and SEM/EDS, while thermal behavior was examined via DSC. Both electrolytes exhibit ionic conductivity ranging from 10−2 to 10−1 mS cm−1 in the temperature range of 10-80 °C, and show oxidative stability above 3.9 V and 4.2 V vs. Li+/Li, for PSU-Jeff40%-LiTFSI and PSU-Jeff60%-LiTFSI, respectively. Preliminary electrochemical evaluation in LiFePO4|Li cells demonstrated the feasibility of employing the synthesized PSU-Jeff-LiTFSI systems as solvent-free polymer electrolytes, although further optimization of electrode/electrolyte interfaces and electrochemical performance under practical operating conditions will be required.

Despite growing interest in metal-organic frameworks (MOFs for protonconductivity applications, monovalent-cation-based MOFs remain comparatively underexplored due to the weaker coordination interactions typically associated with these systems. In this work, we report GR-MOF-28, a novel potassium-based naphthalene tetracarboxylate framework synthesized under mild aqueous conditions at room temperature. Structurally, GR-MOF-28 consists of K2O10 dioctahedra interconnected through tetracarboxylate ligands and coordinated water molecules, generating a confined hydrogen-bond network along the crystallographic channels. The material exhibits proton conductivity values up to 4.3·10-2 S·cm-1 under high relative humidity conditions, placing it among the highest-performing K-based MOFs reported to date. Combined electrochemical impedance spectroscopy and molecular simulations support a water-mediated Grotthusstype proton transport mechanism through the confined hydrogen-bond network. In addition, GR-MOF-28 can be incorporated into a conductive polymer matrix without loss of proton transport properties. These results highlight the potential of underexplored K-based coordination frameworks as proton-conducting materials.

This work investigates the development of composite feedstocks as a preliminary step toward additive manufacturing of RF and terahertz (THz) optical components. Semiconductor nanoparticles are incorporated into a high-density polyethylene (HDPE) matrix with the objective of tailoring the effective refractive index of future waveguide and optical structures. The study focuses on feedstock formulation and compounding strategies aimed at achieving homogeneous particle dispersion and suitable processability for subsequent filament extrusion and fused filament fabrication (FFF). The structural characteristics and dielectric properties of the resulting composites are analyzed as key indicators of their suitability for THz applications. Ongoing work is directed toward filament fabrication and the experimental evaluation of refractive index, transmission, and loss in the terahertz range using frequency-domain spectroscopy, to assess their potential as low-loss optical materials.

The pursuit of next-generation rechargeable batteries that are lightweight, intrinsically safe, sustainable, and mechanically flexible has accelerated interest in all organic solid-state battery concepts based on conducting and redox-active polymers as electrode materials. While many redox polymers exhibit intrinsically low electronic conductivity, conducting polymers can provide substantial electronic transport, highlighting the need for a more nuanced understanding of structure–property relationships in polymer-based electrodes. The key challenges instead arise from polymer swelling in liquid or quasi-solid electrolytes, limited ionic/electronic percolation, and interfacial instabilities at polymer–electrolyte and polymer–current-collector interfaces. This review synthesizes fundamental principles of polymer electrochemistry, including charge transport, redox kinetics, and the evolution of conductivity in electrochemical environments. We critically evaluate major classes of polymer electrode materials, outlining their advantages, limitations, and the design strategies used to enhance performance through molecular engineering, cross-linking, composite formation, and interface modification. Special emphasis is placed on the transition from liquid to solid and quasi-solid electrolytes as a route to mitigate swelling, enhance safety, and stabilize interfacial chemistry. We outline the overarching vision for all-organic solid-state batteries that unite sustainability (bio-derived and recyclable components), intrinsic safety (non-flammable solid electrolytes), mechanical flexibility, and compatibility with low-energy manufacturing. By accurately framing the key challenges and highlighting the transformative potential of polymer-based electrochemical systems, this review provides a roadmap toward practical and scalable all-organic solid-state battery technologies.

Sodium solid electrolytes combining high ionic conductivity, interfacial stability and long-term durability enable reliable all-solid-state sodium batteries, a promising alternative to lithium-based systems. This work presents a comparative study of three representative families of solid electrolytes: NASICON-type ceramics, cross-linked polymer electrolytes and hybrid polymer-in-ceramic systems obtained via in-situ cross-linking within porous ceramic matrices.Structural and morphological analyses reveal that dense NASICON electrolytes favor bulk Na⁺ transport, whereas cross-linked polymer electrolytes form amorphous networks with homogeneous composition. Hybrid electrolytes successfully integrate both phases, yielding improved interfacial contact and structural integrity and handling stability. Thermal characterization shows excellent stability for NASICON, delayed degradation for polymer electrolytes due to cross-linking, and significantly enhanced thermal stability for hybrids (>370 °C), attributed to strong organic-inorganic interactions. Broadband Electric Spectroscopy (0.03–107 Hz; −100 to +150 °C) clarifies conduction mechanisms, where Vogel-Tamman-Fulcher behavior confirms coupling between ion transport and matrix dynamics. Na⁺ migration distances increase with temperature, reaching ∼4 nm (NASICON), ∼10 nm (NPC1000-NaX), and up to 100 nm (HSE-NaX). Favorable interdomain pathways and ClO4⁻ anions enhance structural–dynamic coupling and long-range sodium transport in hybrids. Electrochemical cycling in Na/FePO₄ cells reveals a balance between initial capacity and durability. NASICON displays modest initial capacity (∼85 mAh·g⁻¹) but progressive increases to ∼113 mAh·g⁻¹ after 500 cycles (∼96 % retention), whereas polymer and hybrid electrolytes deliver higher initial capacities (>100 mAh·g⁻¹) but experience capacity decay during prolonged cycling. In summary, NASICON-type electrolytes offer superior long-term durability and stability, whereas polymeric and hybrid systems favor higher initial performance, revealing a trade-off governed by electrolyte architecture.

Solid-state sodium batteries based on polymer electrolytes offer a sustainable solution to overcome current and near-future needs regarding the growing energy and transport electrification issues. In this work, we propose the development of solvent-free polymer electrolytes based on an unsaturated polyether, which, once cross-linked, leads to an amorphous structure at room temperature that favors ionic transport towards reliable and robust solid-state sodium batteries operative at moderate temperatures. Using NaClO4 and NaPF6 as sodium salts, the best polymer electrolyte reaches an ionic conductivity in the range of 0.02 mS & centerdot;cm-1 (30 degrees C)-0.90 mS & centerdot;cm-1 (100 degrees C) with a lifetime superior to 2000 h after plating and stripping. Regarding electrochemical performance, a maximum specific capacity of 110.2 mAh & centerdot;g-1 (C/20) is obtained for the polymer electrolyte including NaClO4, using Na and C/FePO4 as anode and cathode, respectively, which represents about 65% of the theoretical value expected for FePO4. In view of more sustainable energy storage devices, a life cycle assessment is also applied. While the polymer matrix is identified as the main environmental hotspot, the choice of Na salt significantly affects the overall impact, with NaClO4 exhibiting lower climate change and particulate matter impacts than NaPF6.

Thick ceramic LiFePO4 electrodes (800 & micro;m thickness, similar to 104 mg/cm & sup2; mass loading) are fabricated by direct ink writing using a sustainable aqueous-based suspension. This approach enables the formation of three-dimensional electrodes with a controlled porous architecture that enhances electrode/electrolyte wettability and mitigates ion and charge transport limitations typically associated with thick electrodes. The effects of debinding and sintering conditions on the microstructure and electrochemical performance are systematically investigated. In addition, the role of a super conductive carbon black (C65) additive is evaluated as a strategy to enhance electronic conductivity while preserving the ceramic nature of the electrodes. After optimization, fully ceramic binder-free electrodes are obtained. When assembled in full cells with Li4Ti5O12 as the negative electrode and LP30 electrolyte, the optimized electrodes deliver areal capacities from 8.1 mAh/cm & sup2; at C/4 up to 14.4 mAh/cm & sup2; at C/25, retaining 5.9 mAh/cm & sup2; at 1 C.

This work presents the synthesis of a new family of ionic monomers based on a diallylamine structure, designed to develop ionomers capable of conducting several types of monovalent and divalent cations (Li+, Na+, Ca2+, etc.). For this purpose, polymer electrolytes based on lithium and calcium salts at different O/M ratios are prepared using dialyzed poly(oxyethylene) (DIAPOE) as polymer backbone. These polymer electrolytes are fully characterized in terms of microstructure (scanning electronic microscopy, X-Ray mapping), thermal properties (thermogravimetric analysis, differential scanning calorimetry) and ionic conductivity (electrochemical impedance spectroscopy) to elucidate the underlying ion diffusion mechanisms. To validate the reliability of the proposed ionomers and their synthesis procedure, a series of films were produced by crosslinking the corresponding ionic monomers, IMOfr, with an unsaturated poly(oxyethylene), yielding IMOfr-NPC1000 ionomers. The results show that DIAPOE membranes exhibit higher ionic conductivity at high temperatures, achieving values in the range of 10-4 S cm-1. To further promote ionic conductivity at ambient temperature, the cross-linked structure of IMOfr-NPC1000 electrolytes were swelled in different polar solvents, demonstrating a conductivity increase of about two orders of magnitude without compromising their physical integrity. This study paves the way for the development of single-cation conducting ionomeric electrolytes towards safer, reliable and sustainable energy storage devices.

This work presents the modeling and characterization of novel LFP-LTO lithium-ion cells with thick electrodes specifically designed for low-power applications, such as cardiac pacemakers. The selected cells, manufactured in a 2032 coin format with a nominal voltage of 1.9 V and a capacity of 15 mAh, were modeled using equivalent circuit models (ECMs), including both a basic first-order RC (1RC) and an enhanced three-RC-branch (3RC) Thevenin model. A multiobjective optimization strategy was employed to balance accuracy and computational complexity. To capture the dynamic behavior of the cells, a pulse-PRBS (Pulse-Pseudo-Random Binary Sequence) identification signal was applied, enabling precise parameter extraction over a broad frequency spectrum. Experimental results demonstrate that the 3RC model achieves voltage errors below 0.1%, making it suitable for accurate modeling under dynamic load conditions. Furthermore, the series configuration of two LFP-LTO cells reaches a nominal voltage of 3.7 V, matching the requirements of conventional pacemaker batteries. In addition, aging analysis was conducted by applying the same PRBS signal to the cells both before and after accelerated cycling and then modeling the results. These findings confirm that the 3RC model can also serve as a predictive tool for estimating battery aging and health. The proposed modeling methodology offers a reliable and efficient framework for integrating new thick-electrode technologies into biomedical applications.

This study presents a comprehensive life cycle assessment (LCA) of calcium-based polymer electrolytes, aiming to advance sustainable solid-state post-lithium battery technologies. Despite calcium-based solid-state batteries offer safer and more reliable energy storage alternatives, research into their environmental and electrochemical performance remains limited compared to lithium-ion systems. In this work, three polymer electrolytes, based on a cross-linked polymer backbone doped with calcium salts (Ca (TFSI)2, Ca(CF3SO3)2, and CaI2), are studied through LCA and characterized in terms of electrochemical and thermal properties. Notably, it is observed that the salts exhibit a significantly higher contribution to environmental impacts compared to the polymer. The LCA identifies CaI2 as the most environmentally favorable, with climate change emissions of 8.01 center dot 10- 5 kg CO2 equivalent, particulate matter disease incidence of 3.12 center dot 10- 12 cases per kg PM2.5, and negligible ozone depletion impacts (1.27 center dot 10- 6 kg CFC11 eq). Although Ca (TFSI)2 shows higher ozone depletion impact (2.68 center dot 10- 4 kg CFC11 eq) it demonstrates superior ionic conductivity, achieving 0.09 mS center dot cm- 1 at 20 degrees C and 0.4 mS center dot cm- 1 at 90 degrees C. Moreover, differential scanning calorimetry confirms the fully amorphous structure of all electrolytes, with glass transition temperatures ranging from -19.61 degrees C (Ca (TFSI)2) to -38.7 degrees C (CaI2), which ionic conductivity at room temperature. These findings highlight a critical trade-off between environmental impact and electrochemical performance, providing actionable insights for the design of safer, more sustainable energy storage systems.

This work focuses on the development and production of additive-free Li4Ti5O12 thick electrodes with carbon nanotubes processed by powder extrusion moulding to be applied as anodes in high energy density lithium-ion batteries. Li4Ti5O12 is a safer alternative to graphite, featuring a stable solid electrolyte interphase and minimal lattice parameters changes upon lithiation ("zero-strain" behaviour) though its low conductivity necessitates conductive additives, such as carbon nanotubes. Firstly, the commercial pristine powder in terms of composition, particle size distribution, microstructure, and density was characterized. Rheological analysis identified an optimal 50:50 vol% ratio of powder to binder for extrusion. After shaping, the green parts underwent binder removal and sintering at 850 degrees C and 900 degrees C to produce dense, thick electrodes without additional additives. The resulting electrodes were similar to 500 mu m thick, with porosities of 28.5 % (122 mg cm(-2) mass loading) and 22.8 % (132 mg cm(-2) mass loading), respectively. Electrochemical characterization in coin cells against Li and LiFePO4 demonstrated excellent performance. In Li4Ti5O12/Li half-cells, volumetric and areal capacities of 375 mA h cm(-3) and 19 mA h cm(-2) were achieved at C/ 24 (0.89 mA cm(-2)). In full Li4Ti5O12//LiFePO4 cells, the electrodes showed stable cycling over 80 cycles at C/24, delivering similar to 18 mA h cm(-2) and 350 mA h cm(-3), with energy values of similar to 280 mW h g(-1) and 35 mW h cm(-2). These results highlight the potential of powder extrusion moulding for the scalable fabrication of thick ceramic electrodes with outstanding energy and power densities, paving the way toward next-generation lithium-ion batteries.

In this work, an electrochemical study of the iron fumarate metal-organic framework structure MIL-88a was carried out. This MOF exhibits an exceptional characteristic: it alters the parameters of its crystal lattice in response to temperature variations and the specific guest molecules present. Through impedance spectroscopy, we investigated how guest molecules within the pores of MIL-88a influence the material's ionic conductivity and its responsiveness to changing environmental conditions. Based on the data obtained, hybrid membranes based on sulfonated multiblock copolymers of polysulfone and polyphenylsulfone (SPES) doped with MIL-88a were prepared. The distribution of crystallites in the membrane was assessed by using scanning electron microscopy. It was found that crystallites agglomerates reduce the tensile strength of the membrane from 87 to 69 MPa, and from 56 to 42 MPa in the dry and wet forms, respectively. The presence of this MOF doubles the water absorption of the hybrid membranes compared to the pure one, resulting in an improvement of their ionic conductivity from 15.8 to 26.5 mS/cm at 80 degrees C. Hybrid membranes show a high maximum power density (1040 mWcm(-2)) in the fuel single cell test that is comparable to that obtained for commercial perfluoro-sulfonic acid PEMs such as Nafion (R).

To address the growing demands for energy density, power, lifetime, and safety in Li-ion batteries, innovative processing techniques for high-capacity electrodes are essential. This study explores the additive manufacturing of ultra-thick LiFePO4 (LFP) electrodes (similar to 800 mu m) using robocasting, as an alternative to traditional methods like screen printing or pressing. 3D LFP-based electrodes with cellular architectures and high mass loading (similar to 20 mg) are designed to enhance ion transport and energy density by increasing the surface area. Eco-friendly, aqueous-based printable inks are optimized for suitable rheological properties (viscosity, modulus, yield strength), in agreement with scalable and sustainable production. To improve mechanical strength and conductivity, 3 wt% of graphene oxide (GO) or graphene nanoplatelets (GNP) are incorporated to the ink formulation. After printing, 3D structures undergo thermal debinding and sintering to remove inactive components, yielding additive-free electrodes. Microstructural, mechanical, and electrical characterizations reveal that GO incorporation increases Vickers hardness by 50 % without compromising compressive strength. Electrochemical testing with Li4Ti5O12 (LTO) as the anode demonstrates promising performance, with LFP-GO electrodes achieving areal capacities up to 11 mA h cm(-2) (21 mW h cm(-2)) at C/25. These results highlight the potential of robocasting to produce robust, high-performance thick electrodes for next-generation Li-ion batteries.

All-solid-state sodium batteries emerge as an excellent alternative to the conventional Li-ion ones towards more reliable, sustainable and safer large-scale energy storage systems able to overcome the current challenges related to climate change and decarbonization. In this study, we present novel sodium hybrid solid electrolytes based on a sintered porous NASICON structure infiltrated with a polymer electrolyte that crosslinks, via radical polymerization, inside the porous microstructure. The porous ceramic material (Na3.16Zr1.84Y0.16Si2PO12) is obtained by combining tape-casting with low-temperature hot pressing, whereas the polymer electrolyte is based in a polycondensate polymer and two different sodium salts (NaClO4 and NaPF6). The hybrid electrolytes are characterized in terms of microstructure, thermal stability and electrochemical behavior. The galvanostatic cycling was performed at 80 degrees C for both approaches, using a coin cell with configuration Na Hybrid electrolyte FePO4, obtaining a higher discharge capacity of 160.7 mAh g-1 (C/20) with the hybrid electrolyte based on the NaPF6 salt, which corresponds to 90 % of the theoretical capacity value of FePO4, value higher than that obtained using a dense ceramic electrolyte (Na3.16Zr1.84Y0.16Si2PO12), demonstrating the synergistic effect of both electrolytes (ceramic and polymer). The proposed rigid hybrid electrolytes pave the way for the development of safer electrolytes for all-solid-state batteries.

The growing demand for electric vehicles and renewable energy storage has intensified the need for Li-ion batteries with higher energy density. One effective strategy is the use of high mass loading electrodes, which increase the ratio between active and inactive materials. However, conventional tape casting techniques face challenges in producing thick electrodes as mechanical consistency deteriorates beyond a certain thickness. Alternative methods have been explored but often require changes in additives or compromise electrochemical performance. In this work, we present a simple and scalable modification of the traditional electrode fabrication process. By drying the NMP solvent before pressing and applying low-temperature hot pressing (190 °C), we obtain thick (150-650 μm), homogeneous, and mechanically robust electrodes that retain the use of standard additives such as carbon black and polyvinylidene fluoride (PVDF). A full cell composed of LFP/LP30/LTO delivered outstanding results: high areal capacities (17 and 13.5 mAh cm-2 at C/25 and C/4), and exceptional cycling stability with no capacity loss over 300 cycles at C/12, despite a high loading of 120 mg cm-2 (650 μm). This approach requires minimal changes to current industrial processes, offering a promising route for next-generation Li-ion batteries with improved energy density and performance.

Battery technologies based in multivalent charge carriers with ideally two or three electrons transferred per ion exchanged between the electrodes have large promises in raw performance numbers, most often expressed as high energy density, and are also ideally based on raw materials that are widely abundant and less expensive. Yet, these are still globally in their infancy, with some concepts (e.g. Mg metal) being more technologically mature. The challenges to address are derived on one side from the highly polarizing nature of multivalent ions when compared to single valent concepts such as Li+ or Na+ present in Li-ion or Na-ion batteries, and on the other, from the difficulties in achieving efficient metal plating/stripping (which remains the holy grail for lithium). Nonetheless, research performed to date has given some fruits and a clearer view of the challenges ahead. These include technological topics (production of thin and ductile metal foil anodes) but also chemical aspects (electrolytes with high conductivity enabling efficient plating/stripping) or high-capacity cathodes with suitable kinetics (better inorganic hosts for intercalation of such highly polarizable multivalent ions). This roadmap provides an extensive review by experts in the different technologies, which exhibit similarities but also striking differences, of the current state of the art in 2023 and the research directions and strategies currently underway to develop multivalent batteries. The aim is to provide an opinion with respect to the current challenges, potential bottlenecks, and also emerging opportunities for their practical deployment.

Lithium-ion batteries are the most efficient electrochemical energy storage devices. However, there is still room for improvement in terms of safety and energy density, presently limited by conventional tape-casting electrode processing. In this study, a blend of the anodic material Li4Ti5O12 with 2 wt% carbon black has been processed through powder injection moulding (PIM) yielding, after subsequent debinding and sintering processes, to ultra-thick (>500 mu m) ceramic binder-free electrodes. The mixture of Li4Ti5O12 with the thermoplastic binder composed of polypropylene, paraffin wax, and stearic acid is investigated to identify a rheologically suitable feedstock for the PIM process. The resulting disk-type green parts contain 50 vol% of ceramic powder. After removing the binder with solvents and subsequent thermal treatment, the parts are sintered at 900 degrees C, aiming for a relatively high porosity, i.e., 25.7%. The resulting electrodes show very high areal and volumetric capacities up to 26.0 mAhcm(-2) and 403 mAhcm(-3) at C/24, respectively, in a half-cell against lithium metal.

Lithium-ion batteries are widely used in portable electronic devices because of their high energy and power density. To enhance the energy density of these batteries, one strategy involves increasing the active material loading by increasing the thickness of the electrodes. In previous studies, we demonstrated that powder extrusion moulding (PEM) is a scalable and efficient method for producing additive-free LTO and LFP ceramic electrodes, which exhibit remarkable electrochemical performance with thicknesses up to 500 mu m. This study focuses on the preparation and optimisation of the entire manufacturing process for thick ceramic electrodes of LiCoO2 (LCO) with a high mass loading of 180 mg cm-2 using the PEM process. Different powder loadings of mixtures of LCO and a thermoplastic multi-component binder were explored to obtain a formulation suitable for rheology. The optimal formulation comprises 60 vol% of powder. After binder removal via a combination of solvent and thermal treatment, followed by air sintering, parts with varying porosities were obtained. Striking a balance between porosity and thermal degradation is crucial for achieving optimal electrochemical behaviour. Electrochemical evaluations of the electrodes sintered at 900 degrees C and 1000 degrees C revealed areal capacity values as high as 17 mAh cm- 2 at C/25 and 7 mAh cm-2 at C/6.25, respectively. These values far exceed the 1-2 mAh cm-2 obtained from commercial LCO electrodes. These results indicate a strategy for the production of electrodes to fabricate lithium-ion batteries with a low ratio of inactive materials and, therefore, with higher energy densities.