High-throughput and autonomous experimentation generate complex, heterogeneous datasets whose reuse, large-scale analysis, and linking to data from first-principles calculations remain challenging. Here, we report on an operational deployment of the open-source NOMAD Oasis data infrastructure as a digital backbone for daily high-throughput experimental work in a materials discovery group at DTU Nanolab. The customized platform supports the complete experimental workflow in a thin-film laboratory, linking physical inventory items, automated synthesis logs, high-throughput characterization data, and cloud-based analysis within a unified data model. The platform preserves full sample provenance across multi-step workflows and uses unified sample coordinates to enable direct cross-technique correlation. We demonstrate the capabilities of the platform on a combined experimental-computational project centered on phosphosulfide thin-film libraries. The data consists of 12 000 experimental samples acquired during routine operation over 18 months, complemented by more than 800 first-principles calculations - all managed in a unified data platform available at https://nomad.nanolab.dtu.dk/nomad-oasis/gui/search/combinatorial-samples. We show how an open, extensible data infrastructure system supports reproducible workflows, scalable analysis, and long-term data reuse.

Water-in-salt electrolytes (WiSEs) are a promising class of next-generation electrolytes. Unlike classical dilute electrolytes or more conventional battery electrolytes, WiSEs are characterized by their super-concentrated salt content and low water content, which give rise to an expanded electrochemical stability window (ESW). The expansion of the ESW is due in part to the formation of an inorganic solid electrolyte interphase (SEI) that passivates the anode; this principle also proves important in commercial Li-ion batteries, where graphite and Li-metal anodes operate at potentials outside the ESW of conventional carbonate electrolytes, as well as extending beyond Li-ion technologies. Solvation structure and ionic association are key descriptors for understanding the expansion of the ESW. In particular, because the reactions that lead to SEI formation, or to cathode electrolyte interphase (CEI) formation, occur at the electrode-electrolyte interface, the distribution of reactants and their solvation environments is critical. In the absence of reactions, this interfacial distribution is referred to as the electrical double layer (EDL). Here, we further develop and analyze a recently proposed thermodynamic theory of hydration and ionic association in the EDL of WiSEs. We parameterize the theory using bulk molecular dynamics simulations and benchmark it against EDL simulations, finding good qualitative agreement. Using this thermodynamic framework, we rationalize an expansion in the ESW through changes in bulk electrolyte activity, via the Nernst equation, which directly alters electrolyte stability, and through thermodynamic effects on reaction kinetics, via the concentration of reactant species in the Helmholtz layer. Overall, this formalism directly links solvation and ionic aggregation to changes in reactivity, providing key insights into the thermodynamic factors that influence SEI formation in WiSEs. The framework can also be applied to other liquid electrolytes, including conventional carbonate electrolytes, solvent-in-salt systems, and Na-ion electrolytes, to understand how solvation and ionic association influence ESW expansion and SEI formation.

These concluding remarks report on a Faraday Discussion in which angstrom-scale confinement emerged not as a geometric extension of bulk behaviour but as a qualitatively distinct thermodynamic and kinetic regime, with emerging evidence that some of its anomalies may have quantum origins. Opened by the Spiers Lecture of Prof. Lydéric Bocquet, the Discussion covered four sessions: structure and dynamics of confined molecules; stimuli-responsive transport; molecular and ion sieving; and iontronics and emergent neuromorphic effects. Machine-learning molecular dynamics at first-principles accuracy revealed a sharp three-layer structural transition in confined water and asymmetric solvation of OH[-] and H3O[+] under hBN confinement. Active transport control has been demonstrated using light, strain, mechanical force, and solvent composition. Across these studies, surface chemistry and confinement consistently act together, emerging as the main determinants of ion selectivity. In iontronics, memristive-like behaviour has been reported across a remarkably broad range of mechanisms and an even wider variety of nanofluidic platforms, suggesting that such responses may be a pervasive feature of ionic systems whenever coupled transport, interfacial dynamics, and memory effects coexist. Reported origins include asymmetric ion-pair kinetics, energy-barrier rectification in funnel channels, confined water-dipole ordering, coupled capacitive-inductive memory effects, asymmetric electrochemical reactions, and other history-dependent ion-gating and interfacial processes. Across all sessions, a broad consensus emerged that progress on the most important open questions in water/ion transport will depend on close interplay between theory and experiment. At the same time, there was a strong sense that nanofluidics has reached a level of maturity that now makes these challenges tractable, reinforcing a broader excitement across the field.

Metal batteries employing lithium or sodium anodes offer exceptional energy density but are limited by interfacial instability and uneven metal deposition, particularly in anode-free designs where lithium is plated onto a bare current collector. Here, we demonstrate a rapid and scalable method for depositing tin seed layers on copper current collectors using a replacement reaction commonly employed in the electronics industry, enabling coating from aqueous solutions at room temperature. The resulting tin layer acts as an electronically conductive lithophilic seed that potentially improves solid-solid wetting between lithium and the current collector, promoting more uniform lithium electrodeposition in anode-free cells. The mechanistic roles of the tin seed layer and the solid-electrolyte interphase (SEI) are investigated through lithium-tin alloying and de-alloying processes combined with cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), and scanning electrochemical microscopy (SECM). Here, we show that the tin seed layer fundamentally alters the interfacial electrochemistry of copper, enabling faster charge transport across the SEI.

Solid-state batteries show promise as future energy storage systems. However, reactions between oxide and thiophosphate materials at their interface often cause decomposition, which shortens cycle life. Until now, these interfaces have mainly been studied electrochemically after cell cycling. Nonetheless, ageing may occur while cycling, or even when composite electrodes, blends of electroactive materials and solid electrolytes, are ground together and stored in a glovebox for a week. This paper examines how different storage conditions affect composite electrodes made from LiNi0.5Mn0.3Co0.2O2 (NMC532) paired with Li6PS5Cl solid electrolyte. Variables like powder versus pellet form, and storage temperatures at 25 °C or 60 °C, were evaluated. After just one week, results showed that storing the material as pellets accelerated decomposition due to the close contact between the active material and the electrolyte. Ageing for only one week significantly reduced the specific charge and increased the polarisation during cycling compared to fresh samples. These changes stem from bulk modifications, including the formation of side phases, like transition metal sulfides and LiCl, and surface reactions producing Li2S. Detailed electrochemical impedance studies revealed that ionic conduction dropped sharply while electronic conductivity rose because of transition metal sulfide formation. The findings highlight how managing electrode ageing is crucial when developing solid-state batteries featuring composite electrodes.

The mechanical properties of a solid-electrolyte interphase (SEI), such as hardness and Young's modulus, influence the ion transport pathways through the SEI as well as affecting the dendrite formation processes. Moreover, the local composition of the SEI has a strong influence on mechanical variations at small scales, making a thorough understanding of such properties with high detail in depth and with high spatial resolution crucial. Within this contribution, in operando atomic force microscopy (AFM) and nanoindentation are used to investigate the mechanical properties of the SEI in conventional electrolytes in comparison to those in ionic liquids. While both methods have been shown to be powerful tools to investigate SEI formation, distinctive mechanical fingerprints are demonstrated for SEIs formed in carbonate electrolytes on lithium deposited on copper in AFM-based experiments. Such fingerprints change significantly when ionic liquids are used as electrolytes and depend critically on the exact composition. These results are correlated with nanoindentation, performed on freshly cleaved lithium surfaces in an inert atmosphere and carbonate solvents. Additionally, lithium surfaces treated with varying amounts of and exposure times to ionic liquids are studied. In both cases, AFM-based experiments and nanoindentation, higher stiffnesses and storage moduli are found, indicating a highly complex SEI structure.

Coulometric titration time analysis (CTTA) has recently emerged as a powerful technique for quantifying the rate of solid electrolyte interphase (SEI) growth and elucidating the underlying mechanisms governing degradation in solid-state batteries with argyrodite solid electrolytes. However, subsequent studies employing metallic interlayers and variable stack pressures have revealed that CTTA results are highly sensitive to the effective contact area between the solid electrolyte and the current collector. In this work, we further explore CTTA as a SEI characterisation technique to gain more information on its strengths and weaknesses. The findings highlight key challenges when comparing results across samples and propose strategies to mitigate these effects. Moreover, this study contextualises CTTA within the broader suite of SEI characterisation techniques, offering guidance on its optimal implementation and interpretation.

Hydroborate solid electrolytes are attracting increasing attention as alternatives to argyrodite electrolytes for all-solid-state lithium and sodium batteries. In this work, we first summarize recent progress in mixed-anion closo-hydroborate and closo-hydrocarborate electrolytes and derive criteria to select anion compositions that balance ionic conductivity, electrochemical stability, and interface compatibility. Building on a diffusion-limited interphase growth model, we quantitatively compare the interface resistance growth rate of Li3(CB11H12)2(CB9H10) and Li6PS5Cl in contact with lithium metal, lithiated silicon, and delithiated NMC811 by monitoring impedance as a function of time using electrochemical impedance spectroscopy. Despite its lower reductive stability, the hydroborate exhibits substantially slower interface resistance buildup in contact with lithium metal than the argyrodite, emphasizing that the transport properties of the solid electrolyte interphase, rather than the bulk electrolyte stability alone, govern long-term interfacial degradation. In contact with lithiated silicon, both electrolytes show markedly slower resistance growth, with the hydroborate showing higher stability than the argyrodite. In contact with delithiated NMC811, neither electrolyte shows any resistance growth at an open-circuit potential of 3.8 V vs. Li/Li[+]. At 4.1 V vs. Li/Li[+], the hydroborate electrolyte shows resistance growth due to electrolyte oxidation, despite its higher oxidative stability compared to the argyrodite, which shows no resistance growth at this potential. The cell resistance is dominated by the interface resistance at the cathode, highlighting the importance of protective coatings to prevent electrolyte oxidation. Our findings highlight closo-hydroborates and closo-hydrocarborates as promising electrolytes for high-energy solid-state lithium and sodium batteries and underline the critical importance of tailoring interphase composition and transport to unlock their full potential.

Quasi-solid-state lithium-sulfur batteries offer a promising route to combine the high energy density of lithium-sulfur chemistry with improved interfacial stability. However, their performance is limited by the formation of resistive solid-liquid electrolyte interphases at the interface between the solid electrolyte separator and the liquid catholyte. In this work, we investigate solid-liquid electrolyte interphase formation at the interface between an argyrodite-type sulfide solid electrolyte Li5.5PS4.5Cl1.5 and two representative liquid electrolytes: a conventional ether-based electrolyte (LiTFSI in DOL:DME) and an ionic liquid (LiTFSI in EMIMTFSI). Using a combination of time-resolved electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and focussed ion beam scanning electron microscopy, we reveal substantial differences in interphase chemistry, morphology, and transport properties. The ether-based electrolyte undergoes continuous chemical reaction with the sulfide solid electrolyte, forming a thick, inhomogeneous, and highly resistive interphase (∼2000 Ω cm[2] after 250 h), driven in part by dissolution of polysulfide species. In contrast, the ionic liquid electrolyte forms a significantly thinner, layered interphase with a comparatively low area-specific resistance (∼150-220 Ω cm[2]), which remains constant over extended time and during electrochemical cycling. These findings demonstrate that choice of catholyte plays an important role in governing solid-liquid electrolyte interphase formation, and highlights ionic liquids as viable catholytes for stable, low-resistance interfaces in quasi-solid-state lithium-sulfur batteries with argyrodite-type solid electrolyte separators.