Dr. Gustav Graeber
Profil
Forschungsthemen4
Anodenfreie Natrium- und Kalium-Metall-Batterien durch Alkalimetall-Benetzungsstrategien
Quelle ↗Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 03/2023 - 02/2028 Projektleitung: Dr. Gustav Graeber
Effiziente Hochtemperatur-Natrium-Schwefel-Batterien
Quelle ↗Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 05/2026 - 04/2029 Projektleitung: Dr. Gustav Graeber, Prof. Dr. Philipp Adelhelm
Effiziente Hochtemperatur-Natrium-Schwefel-Batterien
Quelle ↗Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 05/2026 - 04/2029 Projektleitung: Dr. Gustav Graeber, Prof. Dr. Philipp Adelhelm
High-performance atmospheric water harvester (HYVEST)
Quelle ↗Förderer: Andere inländische Stiftungen Zeitraum: 01/2026 - 12/2027 Projektleitung: Dr. Gustav Graeber
Mögliche Industrie-Partner10
Stand: 26.4.2026, 19:48:44 (Top-K=20, Min-Cosine=0.4)
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- 21 Treffer60.2%
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Publikationen25
Top 25 nach Zitationen — Quelle: OpenAlex (BAAI/bge-m3 embedded für Matching).
Nature · 461 Zitationen · DOI
Nature Communications · 194 Zitationen · DOI
Abstract A liquid droplet dispensed over a sufficiently hot surface does not make contact but instead hovers on a cushion of its own self-generated vapor. Since its discovery in 1756, this so-called Leidenfrost effect has been intensively studied. Here we report a remarkable self-propulsion mechanism of Leidenfrost droplets against gravity, that we term Leidenfrost droplet trampolining. Leidenfrost droplets gently deposited on fully rigid surfaces experience self-induced spontaneous oscillations and start to gradually bounce from an initial resting altitude to increasing heights, thereby violating the traditionally accepted Leidenfrost equilibrium. We found that the continuously draining vapor cushion initiates and fuels Leidenfrost trampolining by inducing ripples on the droplet bottom surface, which translate into pressure oscillations and induce self-sustained periodic vertical droplet bouncing over a broad range of experimental conditions.
Advanced Materials · 158 Zitationen · DOI
Hygroscopic hydrogels are emerging as scalable and low-cost sorbents for atmospheric water harvesting, dehumidification, passive cooling, and thermal energy storage. However, devices using these materials still exhibit insufficient performance, partly due to the limited water vapor uptake of the hydrogels. Here, the swelling dynamics of hydrogels in aqueous lithiumchloride solutions, the implications on hydrogel salt loading, and the resulting vapor uptake of the synthesized hydrogel-salt composites are characterized. By tuning the salt concentration of the swelling solutions and the cross-linking properties of the gels, hygroscopic hydrogels with extremely high salt loadings are synthesized, which enable unprecedented water uptakes of 1.79 and 3.86 gg<sup>-1</sup> at relative humidity (RH) of 30% and 70%, respectively. At 30% RH, this exceeds previously reported water uptakes of metal-organic frameworks by over 100% and of hydrogels by 15%, bringing the uptake within 93% of the fundamental limit of hygroscopic salts while avoiding leakage problems common in salt solutions. By modeling the salt-vapor equilibria, the maximum leakage-free RH is elucidated as a function of hydrogel uptake and swelling ratio. These insights guide the design of hydrogels with exceptional hygroscopicity that enable sorption-based devices to tackle water scarcity and the global energy crisis.
Nature Physics · 124 Zitationen · DOI
Supercooled droplet freezing on surfaces occurs frequently in nature and industry, often adversely affecting the efficiency and reliability of technological processes. The ability of superhydrophobic surfaces to rapidly shed water and reduce ice adhesion make them promising candidates for resistance to icing. However, the effect of supercooled droplet freezing-with its inherent rapid local heating and explosive vaporization-on the evolution of droplet-substrate interactions, and the resulting implications for the design of icephobic surfaces, are little explored. Here we investigate the freezing of supercooled droplets resting on engineered textured surfaces. On the basis of investigations in which freezing is induced by evacuation of the atmosphere, we determine the surface properties required to promote ice self-expulsion and, simultaneously, identify two mechanisms through which repellency falters. We elucidate these outcomes by balancing (anti-)wetting surface forces with those triggered by recalescent freezing phenomena and demonstrate rationally designed textures to promote ice expulsion. Finally, we consider the complementary case of freezing at atmospheric pressure and subzero temperature, where we observe bottom-up ice suffusion within the surface texture. We then assemble a rational framework for the phenomenology of ice adhesion of supercooled droplets throughout freezing, informing ice-repellent surface design across the phase diagram.
Proceedings of the National Academy of Sciences · 103 Zitationen · DOI
Spontaneous removal of liquid, solidifying liquid and solid forms of matter from surfaces, is of significant importance in nature and technology, where it finds applications ranging from self-cleaning to icephobicity and to condensation systems. However, it is a great challenge to understand fundamentally the complex interaction of rapidly solidifying, typically supercooled, droplets with surfaces, and to harvest benefit from it for the design of intrinsically icephobic materials. Here we report and explain an ice removal mechanism that manifests itself simultaneously with freezing, driving gradual self-dislodging of droplets cooled via evaporation and sublimation (low environmental pressure) or convection (atmospheric pressure) from substrates. The key to successful self-dislodging is that the freezing at the droplet free surface and the droplet contact area with the substrate do not occur simultaneously: The frozen phase boundary moves inward from the droplet free surface toward the droplet-substrate interface, which remains liquid throughout most of the process and freezes last. We observe experimentally, and validate theoretically, that the inward motion of the phase boundary near the substrate drives a gradual reduction in droplet-substrate contact. Concurrently, the droplet lifts from the substrate due to its incompressibility, density differences, and the asymmetric freezing dynamics with inward solidification causing not fully frozen mass to be displaced toward the unsolidified droplet-substrate interface. Depending on surface topography and wetting conditions, we find that this can lead to full dislodging of the ice droplet from a variety of engineered substrates, rendering the latter ice-free.
Scientific Reports · 76 Zitationen · DOI
Driven by its importance in nature and technology, droplet impact on solid surfaces has been studied for decades. To date, research on control of droplet impact outcome has focused on optimizing pre-impact parameters, e.g., droplet size and velocity. Here we follow a different, post-impact, surface engineering approach yielding controlled vectoring and morphing of droplets during and after impact. Surfaces with patterned domains of extreme wettability (high or low) are fabricated and implemented for controlling the impact process during and even after rebound--a previously neglected aspect of impact studies on non-wetting surfaces. For non-rebound cases, droplets can be morphed from spheres to complex shapes--without unwanted loss of liquid. The procedure relies on competition between surface tension and fluid inertial forces, and harnesses the naturally occurring contact-line pinning mechanisms at sharp wettability changes to create viable dry regions in the spread liquid volume. Utilizing the same forces central to morphing, we demonstrate the ability to rebound orthogonally-impacting droplets with an additional non-orthogonal velocity component. We theoretically analyze this capability and derive a We(-.25) dependence of the lateral restitution coefficient. This study offers wettability-engineered surfaces as a new approach to manipulate impacting droplet microvolumes, with ramifications for surface microfluidics and fluid-assisted templating applications.
ACS Nano · 51 Zitationen · DOI
Surface icing affects the safety and performance of numerous processes in technology. Previous studies mostly investigated freezing of individual droplets. The interaction among multiple droplets during freezing is investigated less, especially on nanotextured icephobic surfaces, despite its practical importance as water droplets never appear in isolation, but in groups. Here we show that freezing of a supercooled droplet leads to spontaneous self-heating and induces strong vaporization. The resulting, rapidly propagating vapor front causes immediate cascading freezing of neighboring supercooled droplets upon reaching them. We put forth the explanation that, as the vapor approaches cold neighboring droplets, it can lead to local supersaturation and formation of airborne microscopic ice crystals, which act as freezing nucleation sites. The sequential triggering and propagation of this mechanism results in the rapid freezing of an entire droplet ensemble, resulting in ice coverage of the nanotextured surface. Although cascade freezing is observed in a low-pressure environment, it introduces an unexpected pathway of freezing propagation that can be crucial for the performance of rationally designed icephobic surfaces.
ACS Applied Materials & Interfaces · 50 Zitationen · DOI
Macrotextured superhydrophobic surfaces can reduce droplet-substrate contact times of impacting water droplets; however, surface designs with similar performance for significantly more viscous liquids are missing, despite their importance in nature and technology such as for chemical shielding, food-staining repellency, and supercooled (viscous) water droplet removal in anti-icing applications. Here, we introduce a deterministic, controllable, and upscalable method to fabricate superhydrophobic surfaces with a 3D-printed architecture, combining arrays of alternating surface protrusions and indentations. We show a more than threefold contact time reduction of impacting viscous droplets up to a fluid viscosity of 3.7 mPa·s, which equals 3.7 times the viscosity of water at room temperature, covering the viscosity of many chemicals and supercooled water. On the basis of the combined consideration of the fluid flow within and the simultaneous droplet dynamics above the texture, we recommend future pathways to rationally architecture such surfaces, all realizable with the methodology presented here.
Nano Letters · 30 Zitationen · DOI
Moisture-capturing hydrogels have emerged as attractive sorbent materials capable of converting ambient humidity into liquid water. Recent works have demonstrated exceptional water capture capabilities of hydrogels while simultaneously exploring different strategies to accelerate water capture and release. However, on the material level, an understanding of the intrinsic transport properties of moisture-capturing hydrogels is currently missing, which hinders their rational design. In this work, we combine absorption and desorption experiments of macroscopic hydrogel samples in pure vapor with models of water diffusion in the hydrogels to demonstrate the first measurements of the intrinsic water diffusion coefficient in hydrogel-salt composites. Based on these insights, we pattern hydrogels with micropores to significantly decrease the required absorption and desorption times by 19% and 72%, respectively, while reducing the total water capacity of the hydrogel by only 4%. Thereby, we provide an effective strategy toward hydrogel material optimization, with a particular significance in pure-vapor environments.
Advanced Functional Materials · 25 Zitationen · DOI
Abstract Sorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high‐performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high‐performance, cost‐efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel‐salt composites are shown to be stable under repeated sorption‐desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost‐performance ratio substantially exceeds lithium chloride‐based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low‐cost sorbent materials for future applications in water and energy.
Advanced Functional Materials · 24 Zitationen · DOI
Abstract High‐temperature sodium‐nickel chloride (Na‐NiCl 2 ) batteries are a promising solution for stationary energy storage, but the complex tubular geometry of the solid electrolyte represents a challenge for manufacturing. A planar electrolyte and cell design is more compatible with automated mass production. However, the planar cell design also faces a series of challenges, such as the management of molten phases during cycling. As a result, cycling of planar high‐temperature cells until now focused on moderate areal capacities and current densities. In this work, planar cells capable of integrating cost‐efficient nickel/iron electrodes at a substantially enhanced areal capacity of 150 mAh cm −2 is presented. Due to a low cell resistance during operation at 300 °C, these cells deliver a specific discharge energy of 300 Wh kg −1 at high discharge current densities of 80 mA cm −2 (C/2, 10%–100% state‐of‐charge). This results represent the first demonstration of planar Na‐NiCl 2 cells at a commercially relevant combination of areal capacity, cycling rate, and energy efficiency. It is further identified the secondary molten NaAlCl 4 electrolyte to contribute to the cell capacity during cycling. Mitigating electrochemical decomposition of NaAlCl 4 will play an important role in further enhancing both cycling rates and cycle life of high temperature Na‐NiCl 2 batteries.
Advanced Functional Materials · 24 Zitationen · DOI
Abstract The transition from fossil fuels to renewable energy sources requires economic, high‐performance electrochemical energy storage. High‐temperature sodium‐metal chloride batteries combine long cycle and calendar life, with high specific energy, no self‐discharge, and minimum maintenance requirements, while employing abundant raw materials. However, large‐scale deployment in mobility and stationary storage applications is currently hindered by high production cost of the complex, commercial tubular cells and limited rate capability. The present study introduces sodium‐metal chloride cells with a simple, planar architecture that provide high specific power while maintaining the inherent high specific energy. Rational cathode design, considering critical transport processes and the effect of cathode composition on the cell resistance, enables the development of high‐performance cells with average discharge power of 1022 W kg −1 and discharge energy per cycle of 258 Wh kg −1 on cathode composite level, shown over 140 cycles at an areal capacity of 50 mAh cm −2 . This corresponds to a 3.2C discharge over 80% of full charge. Compared to the best performing planar sodium‐metal chloride cells with similar cycling stability and mass loading in the literature, the presented performance represents an increase in specific power by more than a factor of four, while also raising the specific energy by 74%.
Journal of Power Sources · 23 Zitationen · DOI
Solid electrolytes in combination with alkali-metal anodes offer the potential to enhance battery energy density and safety. The inherent challenges associated with cell pressure management have to be accounted for in the cell design but are not sufficiently understood. Here we present a theoretical study linking the effects of thermal and chemo-mechanical expansion of electrode materials to the stresses acting on tubular and planar solid electrolytes, at the example of the sodium-nickel chloride battery chemistry. Based on our analysis, we derive three strategies to reduce these stresses. Namely, we propose (i) to increase the cell closing temperature during production (ii) to reduce the gas pressure in the cell (e.g. by applying a vacuum), and (iii) to rationally balance the volume of the two electrode compartments. Mechanical considerations developed herein form the foundation for the development of next-generation battery cell designs.
Nature Communications · 22 Zitationen · DOI
Moisture-capturing materials can enable potentially game-changing energy-water technologies such as atmospheric water production, heat storage, and passive cooling. Hydrogel composites recently emerged as outstanding moisture-capturing materials due to their low cost, high affinity for humidity, and design versatility. Despite extensive efforts to experimentally explore the large design space of hydrogels for high-performance moisture capture, there is a critical knowledge gap on our understanding behind the moisture-capture properties of these materials. This missing understanding hinders the fast development of novel hydrogels, material performance enhancements, and device-level optimization. In this work, we combine synthesis and characterization of hydrogel-salt composites to develop and validate a theoretical description that bridges this knowledge gap. Starting from a thermodynamic description of hydrogel-salt composites, we develop models that accurately capture experimentally measured moisture uptakes and sorption enthalpies. We also develop mass transport models that precisely reproduce the dynamic absorption and desorption of moisture into hydrogel-salt composites. Altogether, these results demonstrate the main variables that dominate moisture-capturing properties, showing a negligible role of the polymer in the material performance under all considered cases. Our insights guide the synthesis of next-generation humidity-capturing hydrogels and enable their system-level optimization in ways previously unattainable for critical water-energy applications.
Materials Today Energy · 22 Zitationen · DOI
Dendrite formation limits the cycle life of lithium and sodium metal anodes and remains a major challenge for their integration into next-generation batteries, even when replacing the liquid electrolyte by a solid electrolyte. Voids forming in solid metal anodes at the interface to a solid electrolyte on stripping cause current constrictions on plating and promote dendrite formation. Recent studies showed that alkali metal creep is the primary mechanism for replenishing the voids at room temperature. Here, we investigate plating and stripping of liquid sodium metal from a carbon-coated ceramic Na-β"-alumina electrolyte at 250 °C, thereby eliminating creep-related mass transport limitations. We demonstrate extremely high current densities of up to 2600 mA/cm2 and cumulative plating capacities of >10 Ah/cm2 at 1000 mA/cm2 without dendrite formation. Our results demonstrate that liquid metal anodes can be paired with solid electrolytes, providing a practical solution to suppress dendrite formation at high current densities.
Design of a Compact Multicyclic High-Performance Atmospheric Water Harvester for Arid Environments
2024ACS Energy Letters · 19 Zitationen · DOI
Water scarcity remains a grand challenge across the globe. Sorption-based atmospheric water harvesting (SAWH) is an emerging and promising solution for water scarcity, especially in arid and noncoastal regions. Traditional approaches to AWH such as fog harvesting and dewing are often not applicable in an arid environment (<30% relative humidity (RH)), whereas SAWH has demonstrated great potential to provide fresh water under a wide range of climate conditions. Despite advances in materials development, most demonstrated SAWH devices still lack sufficient water production. In this work, we focus on the adsorption bed design to achieve high water production, multicyclic operation, and a compact form factor (high material loading per heat source contact area). The modeling efforts and experimental validation illustrate an optimized design space with a fin-array adsorption bed enabled by high-density waste heat, which promises 5.826 L<sub>water</sub> kg<sub>sorbent</sub> <sup>-1</sup> day<sup>-1</sup> at 30% RH within a compact 1 L adsorbent bed and commercial adsorbent materials.
Biomaterials Science · 12 Zitationen · DOI
The thrombogenicity of artificial materials comprising ventricular assist devices (VADs) limits their long-term integration in the human body. A living endothelium covering the luminal surface can provide a safe interface working compatibly with blood and circumventing this problem. However, the survival of endothelial cells is endangered by non-physiological hemodynamic conditions generated by VAD function, including high wall shear stress and deformation. Here, we introduce a surface topography comprising hexagonal honeycomb shelters in which cells remodel to generate coherently organized patterns of subcellular compartments. The resulting hexagonal array shows resistance to supraphysiological loads maintaining endothelium integrity and avoiding local discontinuities.
Batteries & Supercaps · 9 Zitationen · DOI
Abstract High‐temperature sodium‐nickel chloride (Na−NiCl 2 ) batteries offer a competitive solution for stationary energy storage due to their long‐term stability, high energy efficiency, and sustainable raw materials. However, scaling up this technology faces challenges related to the costly integration of tubular Na‐β′′‐alumina ceramic electrolytes into hermetically sealed battery cells. Alternative cell designs with a planar Na‐β′′‐alumina ceramic electrolyte have been a focus of research for many years, and a series of achievements were made on cell design, on reduction of the operating temperature, and on the analysis of electrochemical reaction mechanisms. However, the data presented in these reports was derived from laboratory‐scale cells with small area (1–5 cm 2 ). To date, there has been no research conducted on enlarging planar cells to an economically viable size. Here we report the fabrication of large planar Na‐β′′‐alumina electrolytes and their integration into planar Na−NiCl 2 cells with 90 cm 2 active area and >7 Ah capacity. Our cell design enabled cycling at 300 °C for three months, transferring a cumulative capacity of 323 Ah. We discuss design and engineering considerations for large planar high‐temperature cells emphasizing the need for cell stacking to compete with tubular Na−NiCl 2 batteries in terms of mass‐specific energy.
Beyond lithium-ion batteries: Shaping the transition to sustainable electrochemical energy storage
20226 Zitationen · DOI
The lithium-ion (Li-ion) technology has enabled substantial advances in consumer electronics and electric vehicles (EV). However, beyond-Li-ion (BLI) batteries are emerging as potential solutions to satisfy future energy storage requirements. BLI solutions may include other lithium-based technologies or avoid the use of lithium altogether. Recent predictions suggest that only a fundamental technological change can substantially increase the specific energy, energy density, and power capabilities needed for fast-charging EVs and electrified aviation. This upcoming transition to BLI batteries is a unique chance to consider an important but often overlooked design criterion when determining the best Li-ion successor: sustainability. To date, short-term cost has been the focus of industrial technology development, but factoring in the long-term environmental and societal impact of energy storage solutions could make alternative technologies competitive. In the context of EV adoption, legislation has already shown to have a decisive effect in shaping technological change. Now, where a transition to BLI technologies is upcoming, targeted policies can shape the energy storage market to promote a sustainable future and could help to avoid a potential lock-in on Li-ion. Especially in times of collapsing supply chains and global geopolitical tension, countries with limited access to central raw materials required for certain battery technologies could benefit from intensifying their support for technologies that rely on abundant raw materials and recycled components.
3 Zitationen · DOI
ACS Applied Materials & Interfaces · 1 Zitationen · DOI
The development of post-lithium-ion batteries has sparked significant interest in alkali-metal anodes, particularly sodium (Na), potassium (K), and sodium-potassium (Na-K) alloys. Na-K alloys are promising for partially liquid anodes due to their unique low melting points. A critical factor influencing Na-K-based anode performance is wetting behavior, which governs electrical conductivity, mechanical contact, and long-term stability. At the heart of wetting lies surface tension, a fundamental property of solid-liquid-gas interactions. However, the surface tension of alkali metals and their alloys, particularly Na-K systems, remains poorly understood due to experimental and theoretical challenges. This study bridged these gaps by employing Du Noüy ring tensiometry for the first time in alkali-metal systems to measure the surface tension of Na, K, and Na-K alloys across temperatures from ambient to 180 °C. A key innovation in this work is the development of the push-in Du Noüy method, which provided significantly higher precision and reliability compared to the traditional pull-out technique, without requiring a correction factor. The measured surface tension decreased with increasing temperature for the studied Na-K alloys. For instance, for a eutectic Na-K mixture, the surface tension decreases from 121.7 mN m<sup>-1</sup> to 112.2 mN m<sup>-1</sup> when increasing the temperature from ambient to 180 °C. Additionally, this study presented the first use of Gibbs free energy minimization to model the surface tension of the Na-K system. The robust method significantly enhanced the predictive accuracy compared to the previous simplified model, reducing deviations from 25% to 2%. Our findings reveal that surface tension increases with sodium mole fraction in the bulk phase, yet the surface monolayer remains potassium-rich, indicating non-ideal surface behavior. This study deepens the understanding of alkali-metal wetting behavior, providing valuable insights for designing optimized interfaces in next-generation semi-solid alkali-metal batteries.
arXiv (Cornell University) · 1 Zitationen · DOI
Sorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high-performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high-performance, cost-efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel-salt composites are shown to be stable under repeated sorption-desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost-performance ratio substantially exceeds lithium chloride-based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low-cost sorbent materials for future applications in water and energy.
Advanced Functional Materials · DOI
Alkali-Metal Batteries False-color image of heat-treated carbon foam after getting in contact with sodium-potassium alloy. The alloy spontaneously coats parts of the carbon structure and fills some of its pores. Photograph by Johannes Baller, image processing by Gustav Graeber. More information can be found in the Research Article by Gustav Graeber and co-workers (10.1002/adfm.202523169).
ACS Applied Polymer Materials · DOI
The development of flexible, safe, and sustainable energy storage systems is critical for next-generation technologies, including wearable electronics, biomedical devices, and soft robotics. In this work, we provide a systematic investigation of sodium perchlorate-based water-in-salt (WIS) electrolytes embedded in polyacrylamide (PAM) hydrogels as a potential platform for deformable sodium-ion batteries or aqueous supercapacitors. Using Raman spectroscopy, we track the transition from free to intermediate water states with increasing salt concentration, identifying the onset of the WIS regime around 10 mol kg–1. Electrochemical measurements reveal that both the aqueous and hydrogel-based electrolytes exhibit a broadened electrochemical stability window (ESW) at higher salt concentrations, reaching up to 2.75 V. Impedance spectroscopy shows that while aqueous electrolytes achieve higher peak conductivity (156 mS cm–1), hydrogel-based electrolytes offer greater stability across a range of concentrations. This observation was supported by cyclic voltammetry, as it showed enhanced electrochemical stability of the PAM hydrogel compared to the aqueous electrolyte. This comprehensive and systematic study demonstrates that highly concentrated WIS electrolytes can be successfully embedded into PAM hydrogels, while preserving good electrochemical stability and ionic conductivity. This could make them a promising foundation for all-hydrogel, sodium-based energy storage devices that are safe, sustainable, and mechanically compliant.
Open MIND · DOI
This presentation was delivered within the framework of the TwinBat project (101159770). It introduces the application of X-ray computed tomography (XCT) to investigate wetting phenomena, structural evolution, and performance-limiting mechanisms in alkali-metal batteries. The talk highlights operando and ex-situ approaches for gaining volumetric and quantitative insights into sodium- and sodium–potassium-based systems.
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