Tape Casting Technique Research Articles

A La1.85Mg0.15Ce2O7-δ-based ceramic hydrogen pump for stable hydrogen separation out of the H2-CO2 mixtures

Currently, hydrogen is largely produced from steam methane reforming with the H2-and CO2-containing stream as the process gas. It is highly relevant to explore new pathways to efficiently separate hydrogen out of the H2-CO2 mixed gases. In the present work, a novel ceramic hydrogen pump for H2 purification is designed with thin La1.85Mg0.15Ce2O7-δ (LMCO) electrolytes supported by symmetrical Ni-LMCO electrodes, and is fabricated by using the tape casting, tape lamination and co-sintering techniques. Chemical stability and proton conductivities are evaluated for fluorite LMCO oxides in humidified 10 % H2-90 % CO2. Superior stability of LMCO in CO2 allows for stable and selective hydrogen separation out of humidified 10 % H2–90 % CO2. The Faraday’s efficiency decreases pronouncedly with an increase in the operation temperature, e.g., ≈ 30 % at 700 ℃ vs. ≈ 76 % at 500 ℃, due to increasingly high reduction susceptibility of Ce4+ to Ce3+ and the resultant electronic conductivities. A reasonable H2 flux of 0.57 mL·min−1·cm−2 is achieved at 500 °C and 0.25 V with electricity consumption of 0.72 kWh·Nm−3 H2. Operation at a higher pumping voltage of 0.49 V yields a larger H2 flux of 1.16 mL·min−1·cm−2, but simultaneously results in higher electricity consumption of 1.42 kWh·Nm−3 H2. Impedance analysis reveals that the H2 fluxes for the present ceramic hydrogen pump are predominantly limited by high resistances against bulk transport of protons through the LMCO electrolytes as well as sluggish hydrogen oxidation kinetics in humidified 10 % H2–90 % CO2.

A rapid pressureless sintering strategy for LLZTO ceramic solid electrolyte sheets prepared by tape casting

Garnet-type electrolytes are regarded as one of the most promising solid-state electrolytes (SSEs) for lithium-ion batteries due to their potential advantages in terms of energy density, electrochemical stability and safety. To achieve the maximum energy density, it is necessary to ensure that the electrolyte layer is as thin as possible. Nevertheless, thin sheet SSE is more challenging to sinter than pellet due to the greater lithium volatilization from the high surface/volume ratio. Garnet-type SSE (Li6.5La3Zr1.5Ta0.5O12, LLZTO) green tape was prepared by the tape-casting technique. The effects of supporter, sintering temperature and dwell time on the relative density, microstructure and ionic conductivity of thin sheet were investigated. A ceramic SSE sheet with a thickness of 173 μm, a relative density of 97.2 %, an ionic conductivity of 2.02 × 10−4 S/cm at 25 °C and an activation energy of 0.25 eV, was achieved using a rapid pressureless sintering at 1250 °C for 25 min with a MgO supporter. This work offers insights into the practical production of LLZTO sheets.

Active packaging film of poly(lactic acid) incorporated with plant-based essential oils of Trachyspermum ammi as an antimicrobial agent and vanilla as an aroma corrector for waffles

This study developed active packaging films of Polylactic acid incorporated with the plant-based essential oils of Trachyspermum ammi, T. ammi and Vanilla to package waffles, where the antimicrobial property was provided by T. ammi and its odor was masked by vanilla essential oil. Compared to conventional solvent-cast films of smaller sizes requiring a huge amount of solvents, bigger-size PLA-oil films with lower solvent demand were prepared by tape casting technique with 10, 30, and 50 wt% essential oil blends. Films were studied for their morphological, chemical, mechanical, barrier, and antimicrobial properties. The presence and time-bound release of volatile oils from the films was confirmed by infrared spectroscopy, with a continuous decrease of oils from the films till day 30. The plasticizing effect of oils in films was evidenced by decreased tensile strength and crystallinity. In contrast, an increase in elongation at break and water vapor permeability of oil films were also measured. Finally, when packed in PLA films containing 50 wt% blend of both oils, waffles shelf-life extended up to 30 days compared to 2 days for the neat PLA film, where Vanilla was found effective in masking the unpleasant odor of T.ammi as confirmed by sensory analysis.

Tailored multilayered films of the PVDF/Ba0.8Sr0.2TiO3 nanocomposites with surface-modified nanoparticles for superior dielectric and energy storage performance

The multilayer thick film (∼40 μm) of polyvinylidene fluoride-Ba0.8Sr0.2TiO3 (PVDF-BST) have been synthesized by a tape-casting technique. The incorporated BST nanoparticles in the PVDF matrix are functionalized by −PO4−3and −OH−group, which are abbreviated as PBST-P and PBST-H multilayer films. The nature of the functional group attached with the BST nanoparticles is found to strongly influence the dielectric properties, breakdown strength and energy storage behavior of the multilayer films. The dielectric constant (at 1 kHz) of PBST-P multilayer film shows a significant increase (∼30) as compared to PBST-H film (∼22), whereas the tangent loss remains the same. The breakdown strength of PBST-P multilayer film is also high (∼381 MV/m) as compared to the PBST-H film (∼318 MV/m). PBST-P film also possesses high discharge energy density (∼7.97 J/cc at 1800 kV) and ultrahigh energy efficiency (∼98 %). Enhanced dielectric and energy storage properties of PBST-P film is attributed to the strong bridging interaction between the PVDF matrix and BST-P nanofiller, which creates additional dipoles and a strong local electric field at the interfaces. The study may lead towards the novel ways of developing polymer-ceramic nanocomposites for high-energy density capacitors, where the incorporation of functionalized nanoparticles in the polymer matrix is accompanied by the architectured structure.

Design of Ultrathin Asymmetric Composite Electrolytes for Interfacial Stable Solid-State Lithium-Metal Batteries.

Ultrathin composite electrolytes hold great promise for high energy density solid-state lithium metal batteries (SSLMBs). However, finding an electrolyte that can simultaneously balance the interfacial stability of the lithium anode and high-voltage cathode is challenging. The present study utilized the both-side tape casting technique to fabricate ultrathin asymmetric composite electrolytes reinforced with polyimide (PI) fiber membrane, with a thickness of 26.8 μm. The implementation of this asymmetric structural design enables SSLMBs to attain favorable interfacial characteristics, such as exceptional resistance to lithium dendrite puncture and compatibility with high voltages. The suppression of lithium dendrite growth and the extension of the cycle life of lithium symmetric batteries by 4000 h are both experimental and theoretically demonstrated under the dual confinement of PI fiber membrane and Li7La3Zr2O12 ceramic fibers. Furthermore, the integration of multicomponent solid electrolyte interphase and cathode electrolyte interface interfacial layers into the lithium anode and high-voltage cathode enhance theirs cycling stability. With a gravimetric/volumetric energy density of 333.1 Wh kg-1/713.2 Wh L-1, the assembled LiNi0.8Co0.1Mn0.1O2 pouch cell demonstrates exceptional safety. The extensive application of this design concept to SSLMBs enables the resolution of electrode/electrolyte interface issues.

Co-fired lead-free piezoceramic multilayer actuators with ultrahigh electro-strain and remarkable comprehensive properties

Piezoceramic multilayer actuators (MLAs) offer remarkable advantages across various cutting-edge applications, yet the inferior piezoelectric strain and the confined assessment framework of lead-free MLAs constitute substantial obstacles to practical implementation. Herein, we judiciously introduce defect configurations into Ag/Pd co-fired potassium-sodium-niobate-based MLAs by tape-casting technique, achieving a large converse piezoelectric coefficient of 900 pm V−1 at 20 kV cm−1 for each layer, much superior than PZT-5 H counterparts. This lead-free MLA demonstrates fast response time, high temperature stability, impressive fatigue resistance, and good mechanical property. Unlike lead-based material suffering from abundant heat generated under alternating-current electric fields, the high-activated nanosized domains and higher thermal conductivity of this lead-free ceramic collaboratively minimize heat accumulation, presenting advancements for high-frequency utilizations. Moreover, experimental demonstrations reveal that the fast-steering mirror (FSM) apparatus equipped with the lead-free MLA showcases a rotational sensitivity comparable to PZT-based apparatus, exhibiting its extensive prospect for precise positioning and fast-response applications.

Regulating the switching electric field and energy-storage performance in antiferroelectric ceramics via heterogeneous laminated engineering

Antiferroelectric (AFE) ceramics with near-zero remanent polarization originating from unique electric field-induced antiferroelectric-ferroelectric phase transition are of great importance for the application in the energy-storage devices. However, achieving the most widely optimized switching electric field and energy-storage performance of antiferroelectric ceramics has predominantly relied on A/B-site ion doping strategies, often accomplished through a series of experimental and analytical works. In this context, we propose a novel strategy of heterogeneous laminated engineering as a substitute for A/B-site ion doping. This approach allows for a more intuitive regulation of the switching electric field and energy-storage performance in antiferroelectric ceramics without the need for complicated workload. Namely, the ferroelectric Pb0.99(Nb0.9Ta0.1)0.2(Zr0.9Sn0.1)0.8O3 (PNTZS) and antiferroelectric (Pb0.875La0.05Sr0.05) (Zr0.7Sn0.3)O3 (PLSZS) were layer-by-layer laminated using a tape-casting technique. All heterogeneous laminated ceramics exhibit antiferroelectric characteristics, and the magnitude of the switching electric field can be controlled by regulating the ratio between PNTZS and PLSZS. Furthermore, the finite element simulation revealed differences in the local electric fields between PNTZS and PLSZS in heterogeneous laminated ceramics, resulting in a win-win situation for both polarization and the breakdown strength. A large recoverable energy density of 11.2 J cm−3 with ultrahigh energy efficiency of 94.2 % can be obtained under 56 kV mm−1. Moreover, the energy storage performance shows no obvious deterioration in a broad frequency range (1–100 Hz) and temperature range (25–120 °C). Particularly, the outstanding discharge properties with a large discharge energy density of 7.1 J cm−3 and a high power density of 263.7 MW cm−3 show great potential for energy-storage applications. To conclude, a new strategy is opened up herein for designing antiferroelectric energy storage materials, showing the great application potential in the pulse power devices.

Supramolecular Complexation of Metal Oxide Cluster and Non‐Fluorinated Polymer for Large‐Scale Fabrication of Proton Exchange Membranes for High‐Power‐Density Fuel Cells

AbstractCost‐effective, non‐fluorinated polymer proton exchange membranes (PEMs) are highly desirable in emerging hydrogen fuel cells (FCs) technology; however, their low proton conductivities and poor chemical and dimension stabilities hinder their further development as alternatives to commercial Nafion®. Here, we report the inorganic‐organic hybridization strategy by facilely complexing commercial polymers, polyvinyl butyral (PVB), with inorganic molecular nanoparticles, H3PW12O40 (PW) via supramolecular interaction. The strong affinity among them endows the obtained nanocomposites amphiphilicity and further lead to phase separation for bi‐continuous structures with both inter‐connected proton transportation channels and robust polymer scaffold, enabling high proton conductivities, mechanical/dimension stability and barrier performance, and the H2/O2 FCs equipped with the composite PEM show promising power densities and long‐term stability. Interestingly, the hybrid PEM can be fabricated continuously in large scale at challenging ~10 μm thickness via typical tape casting technique originated from their facile complexing strategy and the hybrids’ excellent mechanical properties. This work not only provides potential material systems for commercial PEMs, but also raises interest for the research on hybrid composites for PEMs.

Nanocellulose reinforced starch biocomposite films via tape-casting technique

Nanocellulose reinforced starch biocomposite films via tape-casting technique

Ultrahigh efficiency and enhanced discharge energy density at low loading of nanofiller in trilayered polyvinylidene fluoride‐Ba0.8Sr0.2TiO3 nanocomposites

AbstractPoly(vinylidene)fluoride‐Ba0.8Sr0.2TiO3 (PVDF‐BST) trilayered nanocomposites (with different vol% loading of BST nanoparticles, i.e. 0.75%, 1.50%, 2.25% and 3.00%) has been processed by the tape casting technique. The upper and lower layers of the nanocomposites are casted in the same direction, whereas the middle layer is casted in the opposite direction. The trilayered PVDF‐BST nanocomposite consisting of 3.00 vol% of BST nanoparticles exhibited high dielectric permittivity (~25), low tangent loss (~0.03) and moderately high breakdown strength (BDS ~282 MV/m). Moreover, it also possesses a high discharge energy density (~7.8 J/cc at 1400 kV/cm) and efficiency (~93%). A mechanism for the excellent energy storage behavior and dielectric properties has been proposed. Where, moderately high BDS and low tangent loss are associated with the spatial distribution of the local electric field at interlayer interfaces of PVDF‐BST trilayered nanocomposites, which restricts the conduction of charge carriers at high electric field. The ultrahigh efficiency and enhanced discharge energy density is attributed to the formation of interfacial dipoles at various interfaces such as interlayer, intralayer (PVDF/PVDF), and PVDF/BST interfaces. These investigations would be adopted as a futuristic strategy for developing excellently efficient polymer‐ceramic nanocomposites for the high energy density capacitors used in pulsed power applications.Highlights PVDF‐BST trilayered nanocomposites exhibit high ε′ ~25 and low tanδ ~0.03. Nanocomposite shows ultra‐high energy efficiency ~93% and enhanced UD ~ 7.8 J/cc. Mechanism for the excellent energy storage and dielectric properties Relies on the interfacial dipoles and distribution of the local electric field.

ZrC-SiC closed-cell ceramics with low thermal conductivity: Exploiting unique spherical closed-cell structure through tape casting and CVI techniques

Porous ultra-high temperature ceramics (UHTCs) are recognized as novel candidates for fulfilling the requirements of thermal protection systems of hypersonic aircrafts, as they possess excellent high-temperature resistance and low thermal conductivity. Currently, the reported porous UHTCs predominantly exhibit an open pore structure. By contrast, closed-cell UHTCs, formed by employing ceramic hollow microspheres (HMs) as pore-forming agents, hold great potential for achieving superior thermal insulation performance. Unfortunately, the implementation of this strategy has been hindered by the scarcity of raw materials and preparation techniques.In this paper, ZrC-SiC closed-cell ceramics were first successfully prepared through a combination of tape casting and chemical vapor infiltration (CVI) techniques, utilizing the self-developed ZrC HMs as the primary raw material. The morphology, microstructure, and thermal insulation properties of the obtained ZrC-SiC closed-cell ceramics were investigated. The results indicate that when the content of ZrC HMs is 30 vol.%, the density of the prepared porous ceramics is 2.09 g cm–3, with a closed porosity of 14.05% and a thermal conductivity of 1.69 W (m K)–1. The results clearly prove that the CVI process can successfully convert ZrC HMs into closed pore structures within porous ceramics. The introduction of ZrC HMs suppresses the contribution of free electrons to thermal conductivity and brings about a large number of solid-gas interfaces, which increases the interfacial thermal resistance and significantly reduces the phonon thermal conductivity. Consequently, the as-prepared ZrC-SiC closed-cell ceramics show excellent thermal insulation properties. This study provides a new idea and method for the development of porous UHTCs and offers a more reliable material choice for thermal protection systems.

Aqueous tape casting phosphate ceramic electrolyte membrane for high performance all solid-state lithium metal battery

Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte has caused great attention because of its low cost, high ionic conductivity, and superior air stability. In this work, high quality LATP ceramic electrolyte membranes are fabricated by an aqueous tape casting technique in the air, in contrast to traditional fabrication methods that are usually inefficient and noncontinuous, this technique provides an environment-friendly, scalable, continuous fabrication route for mass production of ceramic electrolyte membranes. The as-prepared LATP ceramic membrane with a relative density of 95.6 % shows a total Li ionic conductivity of 3.8 × 10−4 S cm−1. Simply coated with a flexible polymer electrolyte film on the surface of the LATP ceramic membrane, the solid-solid interfacial polarization between the LATP ceramic membrane and the electrodes can be well controlled under a reasonable level, leading to excellent battery performance. Discharge capacities of 160.6, 157.6, 151.2, 138.9 and 123.9 mAh g−1 at 0.05, 0.1, 0.2, 0.5 and 1 C rates are achieved, respectively. This study demonstrates a promising strategy for commercializing all-solid-state batteries with a cost-effective and scalable manufacturing technique.

Al2O3 dielectric ceramic tapes containing hBN for applications on high-frequency substrates

In this study, we manufactured dielectric alumina (Al2O3) ceramic tapes incorporated with hexagonal boron nitride (hBN) for applications on high-frequency substrates. The ceramic tapes were produced using the tape casting technique. Structural and morphological analyzes show the presence of hBN nanoplatelets dispersed in the Al2O3 matrix, confirming the efficiency of the tape-casting technique and the sintering process. We verified that the crystalline structure of hBN is essential in the dielectric response, showing a reduction in dielectric losses with the incorporation of hBN into the Al2O3 ceramic matrix, making ceramic tapes attractive in dielectric applications. Furthermore, the mechanical properties of the tapes show satisfactory results, reinforcing our findings. Thus, our results become fascinating for applications in high-frequency substrates for electronic transmission devices.

Microstructural and electrochemical properties of Ni-impregnated GDC10 and 8YSZ freeze tape cast scaffolds as fuel electrodes for solid oxide cells

Ni-impregnated Gd0.1Ce0.9O2 and Y0.08Zr0.92O2 fuel electrodes for solid oxide cells are manufactured by the combination of the freeze tape casting and infiltration techniques. Their morphological properties are investigated by scanning electron microscope and X-Ray microtomography while their electrochemical performance is evaluated in symmetrical Y0.08Zr0.92O2-supported button cells by electrochemical impedance spectroscopy. The microstructural analysis of the manufactured scaffolds highlights the characteristic anisotropy of porosity provided by the freeze tape casting method. The average tortuosity factor across the out of plane direction has been calculated equal to 1.38, being considerably lower than the average values of the other components, (τx = 10.2) and (τy = 6.87). The contribution provided by gas diffusion to the overall polarization resistance of the freeze tape cast electrodes has been estimated around 6·10−4 Ω cm2 in the 600–750 °C temperature range, thus lower than the best reported values for the state-of-the-art electrodes featuring sponge-like porosity. The measured impedance data highlighted the higher electrochemical performance of the Ni-impregnated Gd0.1Ce0.9O2 architecture, holding a polarization resistance of 0.823 Ω cm2 at 750 °C, which is regarded as a very promising result for a ∼600 μm thick electrode. The interpretation of the impedance data was supported by the distribution of relaxation times analysis and the complex non-linear least square fit. In particular, the electrochemical investigation highlighted the presence of two major resistive contributions which have been ascribed to the occurrence of a chemical capacitance within the GDC10 lattice (low frequency contribution) and to the multi-layered architecture of the tested symmetrical cells which increases the contact losses (high frequency contribution).

Development of mesoporous ceramic membranes of diatomite/TiO2/Nb2O5 nanocomposites for the treatment of contaminated water

There is an urgent need for low cost and efficient methods for the treatment of contaminated water; in this regard the combination of natural minerals for the preparation of sieves is of special interest. The aim of this work is to develop mesoporous composite ceramic membranes using low-cost minerals: diatomite, niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) powders. The multilayer samples were prepared by the tape casting technique. Initially, four tapes with different relative amounts of the minerals are prepared (diatomite %/ TiO2 %/ Nb2O5 %); the samples are A (1/0/0), B (0.9/0.1/0), C (0.9/0.05/0.05) and D (0.9/0/0.1). These tapes were cut, arranged in a multilayer, pressed, and calcined at 500 °C in presence of air. Then, these multilayers were sintered at 1200 °C in presence of argon to form the ceramic membranes (CM): CM-A, CM-B, CM-C and CM-D. A fifth ceramic membrane CM-E was prepared by combining tapes B and D. The X-ray diffraction characterization identified the phases cristobalite, quartz, anatase, rutile, and H-Nb2O5. The three-point bending test demonstrated a 225 % increase in strength after the incorporation of Nb2O5 and TiO2 particles to the diatomite matrix. For instance, the CM-A and CM-C membranes showed 4.28 and 13.90 MPa, respectively. The monolithic ceramic membranes showed high surface area, the BET analysis indicated a narrowing of pore sizes when are added Nb2O5 and TiO2 particles to diatomite; and showed surface areas of up to 6.161 m2 g-1. The composites presented band gap energies in the range of 3.19–3.70 eV. The ability of the ceramic membranes in the photodegradation of methylene blue in aqueous solutions was tested, the results showed a degradation of up to 87.3 % of the dye.

Highly Stable Protonic Ceramic Electrolysis Cells Based on Air Electrodes with Finger-Like Pores Current Collection Layers Running in High-Steam-Content Air.

The steam content in the air electrode is one of the major factors determining the efficiency and stability of protonic ceramic electrolysis cells (PCECs). In this work, the La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) current collection layer (CCL) film with unique finger-like pores was successfully prepared by the phase-inversion tape-casting technique (PT), which promoted the gas diffusion inside the electrode and effectively improved the stability of the single cell in high-humidity air. A screen-printed LSCF-BaCe0.7Zr0.1Y0.1Yb0.1O3 catalytic active layer (CAL) was also applied to match the thermal expansion coefficient (TEC) values and improve the interface combination. The electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) studies of the symmetric cells showed that when the film was used to match different CALs as an air electrode, the gas diffusion inside the electrode was no longer restricted by the increasing steam content in air. The single cell exhibited a high electrolysis current density of 1 A cm-2 (1.25 V) at 650 °C; furthermore, no performance degradation was observed in this high current density when electrolyzed in air with 40 and 60% humidity for more than 250 h. These results present a simplified and economical scheme to develop air electrodes with high stability in wet air with a high steam content.

Two-layer cathode architecture for high-energy density and high-power density solid state batteries

Solid state batteries with high-energy density and high-power density require the development of thick and energy dense cathodes. Structured cathode electrodes with a double-layer configuration were enabled using a freeze tape casting technique. A bottom dense layer was utilized to enhance the energy density whereas a top porous layer with vertically aligned walls was utilized to enhance the power density. The porous structure of the power layer was achieved by ice templating this layer on top of the densified energy layer of the cathode. This configuration was found to better utilize the active material of the cathodes and was optimized using numerical simulation and computer modeling. Cells with Li metal anode and LiNi0.6Mn0.2Co0.2O2 (NMC622) at approximately 5 and 20 mg/cm2 were cycled at 70 °C at different C-rates. Poly(ethylene oxide) (PEO) with lithium bis-trifluoromethanesulfonimide (LiTFSI) was used for the catholyte and the solid-state electrolyte. The structured cathodes exhibited more than double capacity values as well as better Coulombic efficiency compared to non-structured (single-layer) thick cathodes. Synchrotron X-ray tomography and scanning electron microscopy were used to characterize the microstructure of the cathodes.

Ceria-Nickel Fuel Electrode for Reversible and Fuel Flexible Operation: Scaling-up from Electrolyte- to Electrode-Supported Cell

Solid oxide cells are devices that figure great versatility of fuels whilst in fuel cell mode like biogas, bioalcohols, or hydrogen with no need of high purification, and are also reversible, meaning that the same equipment can operate as an electrolyser being thus capable of converting water/steam or carbon dioxide into fuel for strategic reserve purposes. The FleXelL project, aims to develop a fuel electrode material based on nickel, cerium oxide and yttria-stabilised zirconia to accommodate such virtues – flexibility and reversibility. The physical assessment of the materials was done via X-ray diffraction analysis, which confirmed the phases integrity, and dilatometry outputs that allowed the fabrication of the fuel electrode and electrolyte layers by the tape casting technique with minimum thermal mismatches. The gadolinium-doped ceria protective layer and the lanthanum-strontium cobalt ferrite oxygen electrode were both deposited by spin coating. After the successful manufacturing, the cells were tested electrochemical by polarisation both in fuel cell mode whilst hydrogen or anhydrous methane served as fuels reaching peak power densities as high as 0.7 W.cm-2, or under electrolysis mode achieving current densities above 2 A.cm-2 with a voltage of 1.25 V. The high efficiencies of the cells specially under electrolysis is attributed to the ability of ceria to act as an oxygen buffer, which avoided the deactivation/oxidation of the nickel catalyst under high electrical currents. After operation, the microstructure was investigated with scanning electron microscopy and energy dispersive X-ray spectroscopy to confirm the suitability of the microstructure even after the harsh operation.

Solid Oxide Electrolysis Cells Fabrication: From Single Cells to Batch Production

Energy transition towards a net-zero emission scenario requires, primarily, a significant increase on the renewable energy production capabilities. However, the inherent intermittency of most common renewable sources, added to the limitations of full electrification in some important hard-to-abate sectors (heavy-duty transport, aviation, steel industry...), implies also the need of developing reliable solutions for energy conversion and storage. Here, hydrogen is gaining more and more popularity in the recent years as an effective solution as energy carrier, mostly for the decarbonization of the key industries and transport. Among the different technologies under development for power-to-hydrogen conversion, solid oxide electrolysis (SOE) outstands due to its high conversion efficiency, fuel flexibility (e.g. CO2 electrolysis) and possibility of working in reversible mode (the same device both as electrolyser and fuel cell).Currently behind competing low temperature electrolysis technologies (AEL, PEMEL) in terms of technology readiness, main challenges of SOE today relate to long-term degradation, heat management and design and reliable fabrication of large stacks and systems. Although many projects are lately flourishing in this line, the number of players able to demonstrate an upscaled fabrication of SOE stacks and systems is still limited. The work presented here represents the first step carried out at CENER for the future demonstration of a pilot fabrication line of SOE stacks, from the optimization of functional materials and inks to the fabrication of single cells and building of 2-10 kW stacks.In this study, a fabrication route for SOE planar cells (5x5 cm2) is proposed, including the optimization of every single step of the process: raw material pre-treatment, ink/slurry development, functional printing and sintering. Particular emphasis is placed on ensuring a reliable upscaling for batch production of cells and thus materials are processed in large quantities (~1 L/batch). In terms of functional materials, standard electrode and electrolytes are chosen in a first approach, viz. Ni-YSZ as hydrogen electrode, YSZ as electrolyte and LSM-YSZ as air electrode. For film deposition, tape casting and screen printing techniques are combined. The electrochemical characterization of the fabricated cells will be presented and compared with commercial ones, including degradation analysis.

Two-Layer Structured Cathodes for Solid State Batteries

Designing a robust cathode is one of the major objectives in R&D of lithium-ion batteries. The challenges only get amplified in case of solid state battery cells as the methods for introduction of electrolyte into the cathode structure need to be developed. Ideally, a cathode should support high energy density of a cell which implies necessity for high thickness. This requirement is not trivial to fulfil, both from the standpoint of manufacturing and from the standpoint of overcoming transport limitations in thick cathodes. In this work, inspired by the previous effort on graded porosity cathode design [1], we present a two-layer cathode based on LiNi0.6Mn0.2Co0.2O2 (NMC622). The cathode is built using a densified “energy layer” as a support for the “power layer” in which high porosity and low tortuosity is achieved by the freeze tape casting technique. The distribution of the material in the two layers is guided by numerical simulations based on actual cathode microstructure. The performance of the structured cathodes containing Poly(ethylene oxide) (PEO) with lithium bis-trifluoromethanesulfonimide (LiTFSI) was experimentally investigated in cells containing metallic lithium counter electrode. The structured cathodes showed more than double capacity values and improved Coulombic efficiency compared to uniform cathodes of the same material loading.[1] Kalnaus, S., Livingston, K., Hawley, W.B., Wang, H., Li, J., 2021, “Design and processing for high performance Li ion battery electrodes with double-layer structure J Energy Storage 44 (2021) 103582. Acknowledgments: This research at Oak Ridge National Laboratory (ORNL), managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by Laboratory Directed Research and Development Program at ORNL.