Luis Kitsu Iglesias

Addresses a need to gain scientific insights from one-dimensional (1D) scientific spectra in model-independent ways. A powerful approach for this is to take differences between pairs of spectra and look for meaningful changes that might indicate underlying chemical, structural, or other modifications. The challenge is that the difference curve may contain uninteresting differences such as experimental inconsistencies and benign physical changes such as the effects of thermal expansion. allows researchers to apply simple transformations, or “morphs,” to one of the datasets to remove the unwanted differences, revealing, when they are present, nontrivial differences. is an open-source Python package available on the Python Package Index and conda-forge. Here, we describe its functionality and apply it to solve a range of experimental challenges on diffraction and pair distribution function data from x-rays and neutrons, though we note that it may be applied to any 1D function in principle.

Electrolytes composed of mixed solvents are of significant scientific and technological importance in lithium-ion and beyond-lithium-ion batteries, and more broadly across physical chemistry. Their emergence has highlighted the importance of multiscale phenomena, particularly the development of nanoscale solution heterogeneities. It is therefore essential to assess how these inhomogeneities and nanoscale aggregates influence solvation, transport, and electronic properties. Here we investigate the solution structure and transport properties of aqueous zinc sulfate electrolytes with acetonitrile (ACN) additives, where the addition of ACN leads to improved cyclability. Using complementary anomalous small-angle X-ray scattering, X-ray pair distribution function, electrochemistry, and NMR, we identify the presence of salt-rich-water-rich and salt-poor-ACN-rich nanoheterogeneities and, at higher ACN concentrations, liquid–liquid phase separation. We find that the size of zinc sulfate ion clusters in the water domains increases slightly upon ACN addition, while the ACN-rich domains grow much larger as phase separation is approached. The inverse Haven ratio, determined using the ionic conductivity and diffusivity, is much less than unity and decreases slightly upon addition of ACN, which shows ion–ion interactions. We speculate that the increased ion–ion interactions with increased ACN are a result of a reduction in free water, the increase in zinc sulfate cluster size, and/or an increase in solution tortuosity. This work highlights key phenomena to consider when engineering new water-organic-salt electrolyte systems and establishes a phase diagram for water–ACN–ZnSO4 that can guide advances, such as self-adaptive electrolytes.

Solution species govern crystallization pathways that define the morphology of metal halide perovskite thin films, making understanding their behavior essential for predicting film formation. Despite this importance, the structures of iodoplumbate species in widely used solvents, including N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), remain undetermined. Here, we combine optical absorption spectroscopy, X-ray scattering and spectroscopy, and atomistic simulations to demonstrate solvent coordination strength regulates iodide ligand sharing between Pb centers, thereby shaping iodoplumbate structure in lead iodide (PbI ₂ ) and methylammonium lead iodide (MAPbI ₃ ) inks. Weakly coordinating DMF promotes iodo(poly)plumbate formation (> 1 Pb ²⁺ per species), whereas DMSO stabilizes localized iodo(mono)plumbates. Molecular dynamics and computed absorption spectra attribute ~415 nm absorption in MAPbI ₃ –DMF to the formation of short-lived polyplumbate structures. In situ GIWAXS connects these solvent-dependent solution populations to solvate intermediate formation during drying, establishing mechanistic insights for predicting and controlling perovskite crystallization through ink formulation.

Transient nanoclusters in aqueous ZnSO ₄ electrolytes are revealed with X-ray scattering and molecular dynamics simulations. These nanoclusters exhibit diverse sizes and geometries, influencing ion correlations and transport properties.

Sustainable energy storage is essential to support the transition to renewables and meet the increasing demand for energy. Sodium‐ion batteries (NIBs) are attractive for grid‐scale energy storage due to the abundance and low cost of sodium, sustainability of other battery components, and electrochemical performance. Hard carbon (HC) is a leading anode material for NIBs, but its complex microstructure complicates the understanding of sodium storage mechanisms. Using X‐ray total scattering and density functional theory calculations, this study clarifies how HC's microstructural variations influence sodium storage across the slope (high potential) and plateau (low potential) regions of the potential capacity curve. In the slope region, sodium initially adsorbs at high‐binding energy defect sites and subsequently intercalates between graphene layers, adsorbing at low‐binding energy defect sites, correlating with different slopes observed during initial sodiation. Initial irreversibility arises from sodium trapping at surface defects and solid electrolyte interface formation. In the plateau region, sodium simultaneously intercalates and fills pores, influenced by pore size, interlayer spacing, and defect concentration. HCs with larger pore sizes form larger sodium clusters. The proposed mechanism underscores the role of microstructure engineering in enhancing HC performance and advancing NIBs for grid‐scale energy storage.

Hard carbon (HC) is a leading anode material for sodium-ion batteries, but its complex microstructure complicates understanding of sodium storage mechanisms. Using X-ray total scattering and density functional theory calculations, this study clarifies how HC’s microstructural variations influence sodium storage across the slope (high potential) and plateau (low potential) regions of the potential-capacity curve. In the slope region, sodium initially adsorbs at high-binding energy defect sites and subsequently intercalates between graphene layers, adsorbing at low-binding energy defect sites, correlating with different slopes observed during initial sodiation. Initial irreversibility arises from sodium trapping at surface defects and solid electrolyte interface formation. In the plateau region, sodium simultaneously intercalates and fills pores, influenced by pore size, interlayer spacing, and defect concentration. HCs with larger pore sizes form larger sodium clusters. The proposed mechanism underscores the role of microstructure engineering in enhancing HC performance and advancing sodium-ion batteries for grid-scale energy storage.

Aqueous zinc-ion batteries (ZIBs) employing zinc metal anodes are gaining traction as batteries for moderate to long duration energy storage at scale. However, corrosion of the zinc metal anode through reaction with water limits battery efficiency. Much research in the past few years has focused on additives that decrease hydrogen evolution, but the precise mechanisms by which this takes place are often understudied and remain unclear. In this work, we study the role of an acetonitrile antisolvent additive in improving the performance of aqueous ZnSO₄ electrolytes using experimental and computational techniques. We demonstrate that acetonitrile actively modifies the interfacial chemistry during Zn metal plating, which results in improved performance of acetonitrile-containing electrolytes. Collectively, this work demonstrates the effectiveness of solvent additive systems in battery performance and durability and provides a new framework for future efforts to optimize ion transport and performance in ZIBs.

Hard carbon (HC) is the most promising anode for the commercialization of sodium‐ion batteries (NIBs); however, a general mechanism for sodium storage in HC remains unclear, obstructing the development of highly efficient anodes for NIBs. To elucidate the mechanism of sodium storage in the pores, operando synchrotron small‐angle X‐ray scattering, wide‐angle X‐ray scattering, X‐ray absorption near edge structure, Raman spectroscopy, and galvanostatic measurements are combined. The multimodal approach provides mechanistic insights into the sodium pore‐filling process for different HC microstructures including the pore sizes that are preferentially filled, the extent to which different pore sizes are filled, and how the defect concentration influences pore filling. It is observed that sodium in the larger pores has an increased pseudo‐metallic sodium character consistent with larger sodium clusters. Furthermore, it is shown that the HCs prepared at higher pyrolysis temperatures have a larger capacity from sodium stored in the pores and that sodium intercalation between graphene layers occurs simultaneously with the pore filling in the plateau region. Opportunities are outlined to improve the performance of HC anodes by fully utilizing the pores for sodium storage, helping to pave the way for the commercialization of sodium ion batteries.