Applications In Energy Storage Devices Research Articles

Organic cation‐supported layered vanadate cathode for high‐performance aqueous zinc‐ion batteries

AbstractLayered vanadates are ideal energy storage materials due to their multielectron redox reactions and excellent cation storage capacity. However, their practical application still faces challenges, such as slow reaction kinetics and poor structural stability. In this study, we synthesized [Me2NH2]V3O7 (MNVO), a layered vanadate with expended layer spacing and enhanced pH resistance, using a one‐step simple hydrothermal gram‐scale method. Experimental analyses and density functional theory (DFT) calculations revealed supportive ionic and hydrogen bonding interactions between the thin‐layered [Me2NH2]+ cation and [V3O7]− anion layers, clarifying the energy storage mechanism of the H+/Zn2+ co‐insertion. The synergistic effect of these bonds and oxygen vacancies increased the electronic conductivity and significantly reduced the diffusion energy barrier of the insertion ions, thereby improving the rate capability of the material. In an acidic electrolyte, aqueous zinc‐ion batteries employing MNVO as the cathode exhibited a high specific capacity of 433 mAh g−1 at 0.1 A g−1. The prepared electrodes exhibited a maximum specific capacity of 237 mAh g−1 at 5 A g−1 and maintained a capacity retention of 83.5% after 10,000 cycles. This work introduces a novel approach for advancing layered cathodes, paving the way for their practical application in energy storage devices.

The influence of lattice anharmonicity on the thermal transport properties of two-dimensional MgF2

Abstract Graphene research has ignited interest in two-dimensional (2D) materials. In addition to their unique electronic, mechanical, and optical properties, 2D materials exhibit distinctive thermal transport characteristics. A profound understanding of the microscopic mechanisms underlying the thermal transport properties of 2D materials is crucial for applications in energy conversion and storage devices. However, current studies lack insights into the influence of higher-order lattice anharmonicity on the transport behavior of 2D materials. Thus, this paper focuses on the 2D 1T phase MgF2, analyzing its microscopic thermal transport properties through an anharmonic lattice dynamics approach. Our methodology comprehensively accounts for the effects of quartic anharmonicity and four-phonon scattering on the thermal transport properties of 2D materials.

Exploring the structural and electronic properties of N-doped Ti2C MXenes for novel applications in advanced materials and devices: A DFT study

MXenes, a category of two-dimensional transition metal carbides and nitrides, have attracted significant interest owing to their distinctive characteristics. This study utilizes Density Functional Theory (DFT) to examine the effects of nitrogen doping on the structural and electrical properties of Ti2C MXenes. N-doping induces significant alterations in the lattice structure and electronic properties, culminating in an elevated density of states at the Fermi level, indicating improved conductivity. Furthermore, optical characteristics such as reflectivity and loss function are affected by N-doping, resulting in a shift in the intensity of the reflectivity peak. The alterations provide N-doped Ti2C MXenes viable candidates for advanced applications in energy storage, catalysis, and electronic devices, facilitating future empirical and theoretical investigations in MXene-based materials.

Changes in electronic structure within NiSx (0.60 < x < 1.53) compound series

In this article, changes in electronic properties of NiSx series of films with different sulfur content (x = S/Ni) are studied using X-ray (XPS) and ultra-violet (UPS) photoelectron spectroscopy techniques. NiSx (0.60 < x < 1.53) films are synthesized on native oxide of Si(111) substrates via reactive deposition of Ni and S in an ultra-high vacuum chamber by varying the sulfur pressures and substrate temperatures. The binding energy (BE) of Ni2p3/2 core level, the separation between the Ni2p3/2 main peaks and satellite peaks, and the Ni3d valence band binding energies are all found to vary nearly linearly with the sulfur content in NiSx series of compounds, suggesting a direct dependence of Ni electronic charge on the sulfur content. The shift of the Ni3d and S3p states (to higher and lower BE, respectively) with an increase in the S content provides experimental confirmation of the theoretical prediction previously reported (Wen et al., 2020) [1]. All NiSx films showed density of states (DOS) at the Fermi level, indicating their metallic nature. The Ni2p3/2 binding energy shift of NiSx films are much smaller than that of oxide-based compounds, confirming the significantly more covalent nature of the sulfides. NiSx film grown on Si (111) substrate showed nickel silicide interface formation. This study provides information on the growth and trends in the electronic properties of NiSx relevant for their applications in catalysis, energy storage, and electronic devices.

Novel B6P6X (X=As, Sb) monolayers for antiferromagnetic spintronics and hydrogen storage

Embedding foreign atoms into porous two-dimensional (2D) materials has emerged as a promising strategy to tailor their electronic, magnetic, and adsorption properties, enabling promising applications in energy storage and spintronics devices. In this work, spin-polarized density functional theory (DFT) calculations were employed to investigate the ground state properties and hydrogen (H2) storage of interstitially X = As and Sb atom doped B6P6 (B6P6X) graphenylene monolayers. The resulting B6P6X (X = As, Sb) monolayers exhibit very good mechanical, dynamical, and thermal stabilities with antiferromagnetic (AFM) ground states. Electronic structure calculations reveal AFM semiconducting behavior for both monolayers, with indirect/direct band gaps of 0.71/0.60 eV (PBE) and 2.19/2.14 eV (HSE06) for B6P6As/B6P6Sb, respectively. All B6P6X monolayers exhibit an in-plane easy magnetization axis. The obtained Berezinskii-Kosterlitz–Thouless transition (BKT) temperature value of B6P6Sb monolayer is 268.74 K. Furthermore, the H2 storage capabilities of these B6P6X monolayers were examined. We find that B6P6As and B6P6Sb monolayers can each adsorb up to 48H2 molecules with an average adsorption energy (Ea) of -0.14 eV/H2. The corresponding H2 storage gravimetric capacities are 6.91 wt% for B6P6As@48H2 and 6.10 wt% for B6P6As@48H2, surpassing the U.S. Department of Energy’s 2025 target of 5.50 wt%. These findings highlighting the potential of B6P6X (X = As, Sb) monolayers for AFM spintronics and H2 storage applications.

Ni substituted aluminum doped zinc titanate (AZNT) nano-particles: synthesis and characterization

We synthesized a series of Nickel-substituted Aluminium doped Zinc Titanate (AZNT) nano-particles using hydrothermal method. The structure of synthesized samples was meticulously analyzed using X-ray diffractometer (XRD) while the lattice parameters, crystallite size and volume were calculated with utmost precision. The morphology was further examined using two advanced microscopy techniques Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). These techniques provide detailed imaging and analysis of nano-scale materials. FESEM involves usage of electron beam to scan the surface of a sample and the sample's grain size was estimated. The study investigated the dielectric properties within a frequency range of 10Hz to 50MHz. The dielectric constants and impedance parameters were analyzed. The physical properties of the samples, as determined through these methods, hold promise for practical applications in super capacitors and energy storage devices, offering a glimpse into a potentially transformative future in energy technology.

3D Binder-Free Mo@CoO Electrodes Directly Manufactured in One Step via Electric Discharge Machining for In-Plane Microsupercapacitor Application

Cobalt oxide-based in-plane microsupercapacitors (IPMSCs) stand out as a favorable choice for various applications in energy sources for the Internet of Things (IoT) and other microelectronic devices due to their abundant natural resources and high theoretical specific capacitance. However, the low electronic conductivity of cobalt oxide greatly hinders its further application in energy storage devices. Herein, a new manufacturing method of electric discharging machining (EDM), which is simple, safe, efficient, and environment-friendly, has been developed for synthesizing Mo-doped and oxygen-vacancy-enriched Co-CoO (Mo@Co-CoO) integrated microelectrodes for efficiently constructing Mo@Co-CoO IPMSCs with customized structures in a single step for the first time. The Mo@Co-CoO IPMSCs with three loops (IPMSCs3) exhibited a maximum areal capacitance of 30.4 mF cm−2 at 2 mV s−1. Moreover, the Mo@Co-CoO IPMSCs3 showed good capacitive behavior at a super-high scanning rate of 100 V s−1, which is around 500–1000 times higher than most reported CoO-based electrodes. It is important to note that the IPMSCs were fabricated using a one-step EDM process without any assistance of other material processing techniques, toxic chemicals, low conductivity binders, exceptional current collectors, and conductive fillers. This novel fabrication method developed in this research opens a new avenue to simplify material synthesis, providing a novel way for realizing intelligent, digital, and green manufacturing of various metal oxide materials, microelectrodes, and microdevices.

Crystal structure of nickel orthovanadate (Ni3V2O8) at 299 (3) K and 1323 (8) K: an X-ray diffraction study.

Nickel orthovanadate is a promising material with potential applications in energy storage and photocatalytic devices. The crystal structure of Ni3V2O8 at 299 (3) K and 1323 (8) K was studied using X-ray powder diffraction. The sample was a single-phase orthorhombic kagome-staircase-Ni3(VO4)2-type structure (space group Cmca) at both temperatures. The phase purity and morphology was studied using energy-dispersive X-ray spectroscopy and scanning electron microscopy. The refined unit-cell parameters at 299 (3) K are a = 5.93384 (4) Å, b = 11.38318 (7) Å and c = 8.23818 (5) Å, and at 1323 (8) K are a= 6.02077 (7) Å, b = 11.48838 (7) Å and c = 8.32611 (9) Å. The obtained results indicate thermal expansion anisotropy, with a largest expansivity along a. Variations in Ni-O and V-O bonds with temperature are observed. The variation in the Ni-O bond is about one order higher in magnitude than that of the V-O bond, signifying the high rigidity of V-O bonds. The unit-cell size variations with rising effective ionic volume of the divalent A ion in the A3B2O8 family [A = Ni, Mg, Zn, Co, Mn (experimental data) and also A = Cu, Cd (theoretical data), B = V or As] are analyzed. Based on experimental and theoretical data, trends within the family are observed and the unit-cell size for reported solid solution of nickel (87%) and copper (13%) mixture in (Ni1-xCux)3V2O8 are predicted. Predictions are also provided for some hypothetical A3B2O8 ternary compound and solid solutions.

Boosting supercapacitive performance of SnS2 via trace Pb doping

High-performance electrode materials are crucial for enhancing the performance of supercapacitors. Among various candidates, pseudo-capacitive SnS2 is a promising one due to its high specific capacitance, earth-abundance, nontoxicity as well as low-cost. However, its actual electrochemical performance is restricted owing to the poor intrinsic conductivity and current fabrication processes on improving the conductivity are usually complicated. In this study, based on first-principles calculations, Pb doping is introduced to enhance the conductivity of SnS2. Pb-doped SnS2 nanosheets are synthesized via a simple one-step hydrothermal method. With trace Pb doping (Pbo.o1SnS2), an impressive 4-order-of-magnitude increase in conductivity was achieved compared to pristine SnS2. Furthermore, Pb-doped SnS2 nanosheets exhibit a superior mass-specific capacitance of 533.7 F g−1 at 50 mV s−1 and excellent long-term capacitance retention of 90.2 % over 100,000 cycles at 5 A g−1. This study presents a simple and effective approach to enhancing the supercapacitor performance of SnS2 and advances the practical applications of electrochemical energy storage devices based on 2D materials.

Synthesis of Aluminum Oxide (Al2O3) Nanoparticles Decorated With Polymeric Carbon (Al2O3/AC) Nanocomposites for High Specific Capacitance Value

ABSTRACTAluminum oxide nanoparticles/activated carbon (Al2O3NPs/AC) nanocomposite were synthesized using an optimized sol–gel synthesis method. Various characterization techniques, including x‐ray, field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FTIR), UV–visible spectroscopy and cyclic voltammetry, were employed electrochemical properties of the prepared samples. X‐ray diffraction (XRD) analysis revealed higher crystal plane intensities in Al2O3NPs compared to Al2O3/AC nanocomposites. The average crystallite size was determined to be 32 nm for Al2O3 NPs and 20 nm for Al2O3/AC nanocomposites. FE‐SEM showcased the agglomeration of Al2O3 NPs, while the composite exhibited agglomerated Al2O3 NPs embedded in Al2O3/AC nanocomposites. It was found that the band gaps of Al2O3/AC nanocomposite and Al2O3 NPs were 5.5 and 5.6 eV, respectively. Electrochemical analysis through cyclic voltammetry demonstrated that the specific capacitance of Al2O3/AC nanocomposites was six times higher than Al2O3 NPs. This comprehensive investigation provides valuable insights into the enhanced electrochemical performance of the Al2O3/AC nanocomposites, suggesting its potential application in energy storage devices.

Pr2CuO4/MWCNT/MXene/PANI: A novel quaternary composite with tunable properties for potential applications in optoelectronics and energy storage devices

Pr2CuO4/MXene/MWCNT and PANI composites were synthesized for symmetric supercapacitor applications using a simple hydrothermal and in-situ polymerization technique. Pr2CuO4/ MXene/MWCNT and PANI were of ratios 40:60 (PC1), 50:50 (PC2), and 60:40 (PC3). Composites had a tetragonal single phase of Pr2CuO4 with a preferred orientation peak along (103) plane. FTIR confirmed functional bands of all constituents of the composite. Porous morphology was confirmed by scanning electron microscopy (SEM) beneficial for energy storage capacity. The PC2 Composite possessed the widest absorption range and the smallest band gap energy. The dielectric constant of PC2, was the highest than pure Pr2CuO4 and the other composites. Coercivity and saturation magnetization for the composites decreased with decreasing Pr2CuO4 percentage, producing less eddy currents, which reduced energy dissipation and contributed to the increased efficiency of capacitors and inductors. The best ratio of Pr2CuO4/ MXene/MWCNT and PANI was 50:50 for increasing rate capability. This ratio enhanced surface area, charge storage capacity, specific capacity, and impedance behaviour. The optimized PC2 (Pr2CuO4/MXene/MWCNT: PANI 50:50) electrode exhibited exceptional electrochemical performance, achieving volumetric and gravimetric capacitance values of 2611.47 Fg−1 at 2 Ag−1. This enhanced performance can be explained by the combined effects of Pr2CuO4/MWCNT/PANI, which actively promoted pseudocapacitance and impeded MXene restacking. An excellent candidate for advanced energy storage systems, the electrode has an energy density of 58.032 Whkg−1 and remarkable rate capabilities.

Bay-substituted Perylene diimides (PDIs) as redox mediators in dye-sensitized solar cells and active electrode material in supercapacitors

In recent years, innovations in materials design have improved the optoelectronic properties of advanced materials and facilitated their efficient utilization. A significant amount of research has been conducted on developing perylene diimide (PDI) dyes for their use in various energy-related applications. In the present work, we have synthesized bay-substituted PDI derivatives and explored their dual applications in energy harvesting and storage devices. The nucleophilic substitution reaction of 1,7/1,6-brominated Val-PDI was performed by using 2-naphthol (N) and its Nitrogen analogue 8-hydroxy quinoline (Q) for analysing the effect of N-heterocycle at the bay position. The prepared 1,7 (N1/Q1) and 1,6 (N2/Q2) PDIs underwent thorough photophysical and electrochemical analyses and their structures were optimized through density functional theory (DFT) using B3LYP approach with a 6-31+G (d,p) basis set. Although all the prepared bay-substituted PDIs showed reasonable redox activity, N1 was chosen as an electrolyte dopant in dye-sensitized solar cells (DSSC) owing to its band alignment. This aided in enhanced electron lifetime and charge transfer properties, which led to an enhanced efficiency of 2.04 % while the conventional DSSC delivered only 1.84 % at 200 W m−2 illumination. Additionally, the symmetrical supercapacitor fabricated by using Q1 as electrode material generated a high specific capacitance of 146.54 F g−1. Thus, the proposed work opens avenues for the utility of bay-substituted PDI derivatives for organic electronic applications.

Electrochemical performance of graphene oxide synthesized from graphitic spent potlining for energy storage application

The hazardous nature of spent pot lining (SPL) generated from aluminum smelters poses environmental challenges due to its high fluoride and cyanide content. However, techniques and recent studies have shown that SPL can be converted into valuable carbon-based materials through innovative recycling with potential applications in energy storage devices. This work presents an electrochemical performance evaluation of graphene oxide (GO) electrodes derived from acid-treated SPL for supercapacitor applications. The SPL-derived graphene oxide (SPL-GO) was synthesized via a facile and scalable improved Tour method. SPL-GO electrodes were fabricated by drip-coating SPL-GO/PVDF/DMF suspension on nickel foams. The morphology, structure, and chemical composition of the SPL-GO were characterized using advanced techniques such as energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), Fourier transforms infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). The electrochemical properties of the SPL-GO in 3 M KOH were characterized with a three-electrode system using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements. The results demonstrate that SPL-GO exhibits a relatively high specific capacitance of 762.90 F/g at 1 A/g with corresponding power and energy densities of 502 W/kg and 106.60 Wh/kg, respectively. Additionally, excellent cycling stability of 85.4 % was achieved after 10,000 cycles with a coulombic efficiency of 95.23 %. These results suggest a superior rate capability of SPL-GO, rendering it a viable candidate for supercapacitor applications. Furthermore, this work sets the foundation for the sustainable use of industrial waste in energy storage devices, suggesting a novel, eco-friendly material for practical supercapacitor applications.

High-performance NF-loaded F-NiFe-LDH/rGO nanoflower/nanosheet composite electrode material achieving enhanced specific capacitance and energy density for supercapacitor

High-performance nanostructured F-NiFe-LDH/rGO composite electrode materials with F-NiFe-LDH nanoflowers and rGO nanosheets are synthesized in a controlled hydrothermal method by leveraging the strong synergistic effects between the components, enabling the construction of F-NiFe-LDH/rGO//AC asymmetric supercapacitors. The incorporation of rGO significantly enhances electron transport, resulting in an exceptional specific capacitance of 2860 F g−1 at a current density of 1 A g−1, with a remarkable capacity retention of 102 % after 1000 cycles. This represents a notable improvement in electrochemical energy storage, with surface-controlled capacitance contributing more in alkaline electrolytes for F-NiFe-LDH/rGO composite compared to F-NiFe-LDH alone. The asymmetric supercapacitor device exhibits a specific capacitance of 354 F g−1 at 1 A g−1, maintaining 92.31 % of its initial capacitance after 1000 charge/discharge cycles at 5 A g−1, and achieves an impressive energy density of 110 Wh kg−1 at 1 A g−1. The innovation of this work lies in the controllable preparation of nanostructured F-NiFe-LDH-rGO supercapacitor electrode material with enhanced specific capacitance and energy density by the synergistic effect between F-NiFe-LDH and rGO. This work offers a solid foundation for creating high-performance supercapacitor electrode materials and devices for energy storage applications.

Mimicking Antiferroelectrics with Ferroelectric Superlattices.

Antiferroelectric oxides are promising materials for applications in high-density energy storage, solid-state cooling, and negative capacitance devices. However, the range of oxide antiferroelectrics available today is rather limited. In this work, it is demonstrated that antiferroelectric properties can be electrostatically engineered in artificially layered ferroelectric superlattices. Using a combination of synchrotron X-ray nanodiffraction, scanning transmission electron microscopy, macroscopic electrical measurements, and lateral and vertical piezoresponse force microscopy in parallel-plate capacitor geometry, a highly reversible field-induced transition is observed from a stable in-plane polarized state to a state with in-plane and out-of-plane polarized nanodomains that mimics, at the domain level, the nonpolar to polar transition of traditional antiferroelectrics, with corresponding polarization-voltage double hysteresis and comparable energy storage capacity. Furthermore, it is found that such superlattices exhibit large out-of-plane dielectric responses without involving flux-closure domain dynamics. These results demonstrate that electrostatic and strain engineering in artificially layered materials offers a promising route for the creation of synthetic antiferroelectrics.

Remarkable energy storage performance of BiFeO3-based high-entropy lead-free ceramics and multilayers

Electrostatic energy storage capacitors featuring fast charge–discharge capability play an indispensable role in pulsed power capacitors. However, the inverse correlation between polarization and dielectric breakdown strength (Eb) is the main obstacle limiting the access to high recoverable energy storage density (Wrec) and high efficiency (η). In this work, we designed a series of novel (1-x)BiFeO3-x(Ba0.2Sr0.2Ca0.2Bi0.2Na0.2)TiO3 (BF-xBSCBNT, x = 0.4–1.0) high-entropy lead-free relaxor ferroelectric ceramics. The synergy of refined grain size, broadened band gap, and core–shell microstructure is well-investigated by experimental results and phase-field simulations. High polarization difference is achieved by the strengthened relaxation behavior and the dominated polar nanoregions (PNRs). Both high Wrec of 6.0 J/cm3 and η of 81.1 % are achieved in the BF–0.8BSCBNT ceramics. In particular, a remarkable Wrec of 12.1 J/cm3 with a η of 86.1 % are obtained in the multilayer ceramic capacitors (MLCCs) fabricated from the x = 0.8 composition. Excellent temperature stability (<4.0 % in the range of 25–140 °C) and frequency stability (<6.2 % in the range of 1–500 Hz) are also achieved in MLCCs. The excellent energy storage performance demonstrates that high-entropy strategy is effective to develop novel lead-fee ceramics and devices for energy storage applications.

Integration and Characterization of Synthetic Biodegradable Polymer (PVA) with Graphite Oxide (GO) for Performance Assessment in Sustainable Electrochemical Devices

AbstractIn recent years, the demand for sustainable materials in electrochemical devices has driven the exploration of innovative composites. This study focuses on the integration and characterization of synthetic biodegradable polymer polyvinyl alcohol (PVA) with graphite oxide (GO) to evaluate their performance in sustainable electrochemical applications. PVA, known for its biodegradability and biocompatibility, was combined with GO to leverage its excellent electrical conductivity and large surface area. Microbial fuel cells (MFCs) represent a promising electrochemical biosynthesis technology that harnesses the enzymatic activities using microbes to produce energy from organic substrates. This renewable energy approach relies on the synergistic interaction between electrochemically active bacteria and electrode materials to facilitate electron transfer and power generation. Applications of MFCs range from wastewater treatment to sustainable power generation in remote or resource-limited settings. This study explores recent advances in MFC technology, challenges in scaling up for practical applications, and prospects for integrating MFCs into renewable energy strategies. The nano composite membrane was evaluated for structural, morphological, crystalline, and thermal properties by using Fourier Transform Infrared Spectroscopic (FTIR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and UV- visible spectroscopy. Additionally, the biodegradability of the composite was assessed, confirming that it maintains its environmental benefits while offering improved performance for potential applications in sustainable energy storage and conversion devices. This work provides a promising avenue for the development of eco-friendly electrochemical devices with optimized performance characteristics.

Construction of hierarchical and core-shell structured Co3O4@MnO2@NiO nanoarrays as binder-free electrodes for high-performance asymmetric supercapacitors

Remarkable specific capacity and excellent cycle stability of the electrode materials are vital prerequisites for their practical applications. Transition metal oxide-based materials have been extensively explored and employed as electrode materials for asymmetric supercapacitors. However, the actual specific capacitances of these materials are still far lower than their theoretically predicted values. Thus, it is essential to design transition metal oxide with novel structures in order to maximize their specific capacity and cycle stability. Herein, we constructs hierarchical and core-shell structured Co3O4@MnO2@NiO arrays on nickel foam (Co3O4@MnO2@NiO/NF) through a three-step hydrothermal-annealing process, and use them as a direct binder-free electrode for pseudocapacitors. The as-prepared layered hierarchical Co3O4@MnO2@NiO/NF electrode exhibits an impressive specific capacitance of 6.42 F cm−2 (2054 F g−1) at 1 mA cm−2 in a three-electrode configuration, which is largely because of the synergistic effect among Co3O4, MnO2 and NiO. Furthermore, the 3D nanoarray structure can provides a larger specific surface area, a rapid diffusion path, and more active sites that allow to achieve improved electrochemical performance. In addition, the assembled Co3O4@MnO2@NiO/NF//AC/NF ASC all-solid-state asymmetric supercapacitor (ASC) displays a remarkable energy density (30.7 Wh kg−1 at 400.4 W kg−1), demonstrating that this all-solid-state ASC owns considerable potential for practical applications in such high-performance energy storage devices.

Tutton salt (NH4)2Zn(SO4)2(H2O)6: thermostructural, spectroscopic, Hirshfeld surface, and DFT investigations

ContextAmmonium Tutton salts have been widely studied in recent years due to their thermostructural properties, which make them promising compounds for application in thermochemical energy storage devices. In this work, a detailed experimental study of the Tutton salt with the formula (NH4)2Zn(SO4)2(H2O)6 is carried out. Its structural, vibrational, and thermal properties are analyzed and discussed. Powder X-ray diffraction (PXRD) studies confirm that the compound crystallizes in a structure of a Tutton salt, with monoclinic symmetry and P21/a space group. The Hirshfeld surface analysis results indicate that the main contacts stabilizing the material crystal lattice are H···O/O···H, H···H, and O···O. In addition, a typical behavior of an insulating material is confirmed based on the electronic bandgap calculated from the band structure and experimental absorption coefficient. The Raman and infrared spectra calculated using DFT are in a good agreement with the respective experimental spectroscopic results. Thermal analysis in the range from 300 to 773 K reveals one exothermic and several endothermic events that are investigated using PXRD measurements as a function of temperature. With increasing temperature, two new structural phases are identified, one of which is resolved using the Le Bail method. Our findings suggest that the salt (NH4)2Zn(SO4)2(H2O)6 is a promising thermochemical material suitable for the development of heat storage systems, due to its low dehydration temperature (≈ 330 K), high enthalpy of dehydration (122.43 kJ/mol of H2O), and hydration after 24 h.MethodsComputational studies using Hirshfeld surfaces and void analysis are conducted to identify and quantify the intermolecular contacts occurring in the crystal structure. Furthermore, geometry optimization calculations are performed based on density functional theory (DFT) using the PBE functional and norm-conserving pseudopotentials implemented in the Cambridge Serial Total Energy Package (CASTEP). The primitive unit cell optimization was conducted using the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm. The electronic properties of band structure and density of states, and vibrational modes of the optimized crystal lattice are calculated and analyzed.Graphical abstract

Iron-Catalyzed Laser-Induced Graphitization - Multiscale Analysis of the Structural Evolution and Underlying Mechanism.

The transition to sustainable materials and eco-efficient processes in commercial electronics is a driving force in developing green electronics. Iron-catalyzed laser-induced graphitization (IC-LIG) has been demonstrated as a promising approach for rendering biomaterials electrically conductive. To optimize the IC-LIG process and fully exploit its potential for future green electronics, it is crucial to gain deeper insights into its catalyzation mechanism and structural evolution. However, this is challenging due to the rapid nature of the laser-induced graphitization process. Therefore, multiscale preparation techniques, including ultramicrotomy of the cross-sectional transition zone from precursor to fully graphitized IC-LIG electrode, are employed to virtually freeze the IC-LIG process in time. Complementary characterization is performed to generate a 3D model that integrates nanoscale findings within a mesoscopic framework. This enabled tracing the growth and migration behavior of catalytic iron nanoparticles and their role during the catalytic laser-graphitization process. A three-layered arrangement of the IC-LIG electrode is identified including a highly graphitized top layer with an interplanar spacing of 0.343nm. The middle layer contained γ-iron nanoparticles encapsulated in graphitic shells. A comparison with catalyst-free laser graphitization approaches highlights the unique opportunities that IC-LIG offers and discuss potential applications in energy storage devices, catalysts, sensors, and beyond.