Salt Matrix Research Articles

Influence of Lithium Triflate Salt Concentration on Structural, Thermal, Electrochemical, and Ionic Conductivity Properties of Cassava Starch Solid Biopolymer Electrolytes.

Cassava starch solid biopolymer electrolyte (SBPE) films were prepared by a thermochemical method with different concentrations of lithium triflate (LiTFT) as a dopant salt. The process began with dispersing cassava starch in water, followed by heating to facilitate gelatinization; subsequently, plasticizers and LiTFT were added at differing concentrations. The infrared spectroscopy analysis (FTIR-ATR) showed variations in the wavenumber of some characteristic bands of starch, thus evidencing the interaction between the LiTFT salt and biopolymeric matrix. The short-range crystallinity index, determined by the ratio of COH to COC bands, exhibited the highest crystallinity in the salt-free SBPEs and the lowest in the SBPEs with a concentration ratio (Xm) of 0.17. The thermogravimetric analysis demonstrated that the salt addition increased the dehydration process temperature by 5 °C. Additionally, the thermal decomposition processes were shown at lower temperatures after the addition of the LiTFT salt into the SBPEs. The differential scanning calorimetry showed that the addition of the salt affected the endothermic process related to the degradation of the packing of the starch molecules, which occurred at 70 °C in the salt-free SBPEs and at lower temperatures (2 or 3 °C less) in the films that contained the LiTFT salt at different concentrations. The cyclic voltammetry analysis of the SBPE films identified the redox processes of the glucose units in all the samples, with observed differences in peak potentials (Ep) and peak currents (Ip) across various salt concentrations. Electrochemical impedance spectroscopy was used to establish the equivalent circuit model Rf-(Cdl/(Rct-(CPE/Rre))) and determine the electrochemical parameters, revealing a higher conduction value of 2.72 × 10-3 S cm-1 for the SBPEs with Xm = 17 and a lower conduction of 5.80 × 10-4 S cm-1 in the salt-free SBPEs. It was concluded that the concentration of LiTFT salt in the cassava starch SBPE films influences their morphology and slightly reduces their thermal stability. Furthermore, the electrochemical behavior is affected in terms of variations in the redox potentials of the glucose units of the biopolymer and in their ionic conductivity.

Rational design of long wavelength solid-state fluorescent carbon dots based on zirconium

As a new type of zero dimensional carbon based fluorescent nanomaterial, carbon dots (CDs) have been studied and developed for many years. Various methods have been explored to prepare multicolor CDs to achieve tunable fluorescence of CDs. However, synthesizing fluorescent CDs located in the long wavelength emission region remains a challenge. Here, through a simple one-step solvothermal method using anhydrous citric acid (CA) as the raw material, ZrCl4 as both a metal element dopant and an inorganic salt matrix, and NH3·H2O as nitrogen source, Zr-doped CDs (Zr-CDs) solution with long wavelength fluorescence emission and solid powders with blue fluorescence can be obtained simultaneously. By optimizing the usage of ZrCl4, the fluorescence emission of the prepared CDs red shifted from 596 nm to 650 nm. The introduction of Zr4+ can cause a significant redshift. In addition, based on the sensitivity of CDs to oxygen, they can be used for the detection of trace amounts of H2O2. When using metal-organic framework (MOF) to encapsulate the Zr-CDs which is in the solution, optically stable CD@MOF powders can be obtained, which can be used for the construction of red light-emitting diodes (LEDs), demonstrating its potential application in the field of solid-state lighting. The synthesis technology is expected to provide favorable technical support for the future development of CDs.

Recent advances in high-performance liquid chromatography tandem mass spectrometry techniques for analysis of DNA damage and epigenetic modifications

Environmental exposure would cause DNA damage and epigenetic modification changes, potentially resulting in physiological dysfunction, thereby triggering diseases and even cancer. DNA damage and epigenetic modifications are thus promising biomarkers for environmental exposures and disease states. Benefiting from its high sensitivity and accuracy, high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is considered the “gold standard technique” for investigating epigenetic DNA modifications. This review summarizes the recent advancements of UHPLC-MS/MS-based technologies for DNA damage and epigenetic modifications analysis, mainly focusing on the innovative methods developed for UHPLC-MS/MS-related pretreatment technologies containing efficient genomic DNA digestion and effective removal of the inorganic salt matrix, and the new strategies for improving detection sensitivity of liquid chromatography-mass spectrometry. Moreover, we also summarized the novel hyphenated techniques of the advanced UHPLC-MS/MS coupled with other separation and analysis methods for the measurement of DNA damage and epigenetic modification changes in special regions and fragments of chromosomes.

Unveiling ionic structure in the LiF-NdF3 molten salt system as determined by Raman spectroscopy and quantum chemical calculations

Understanding the structural intricacies of LiF–NdF3 molten salts is of paramount importance for advancing the neodymium electrolysis technology. In this study, the vibrational structure of a LiF–NdF3 molten salt with a LiF/NdF3 molar ratio of 1 was analyzed through in situ Raman spectroscopy, coupled with an in-depth analysis of the ionic structure using molecular simulation techniques. This investigation revealed the presence of various species, including NdF63−, NdF52−, NdF4−, and Nd2F7−, in the molten salt. The primary bands corresponding to these ions were unambiguously identified at wavenumbers of 400, 443, and 491 cm−1, with an intriguing overlapping band at 491 cm−1 corresponding to Nd2F7− and NdF4−. Notably, the results revealed a network of interconversion pathways among these species within the LiF–NdF3 molten salt. Remarkably, Nd2F7− exhibited D3d and D3h group symmetry structures, with a small single-point energy difference of only 0.43 kcal/mol, highlighting their uniform coexistence and stability within the molten salt matrix. Moreover, anodic perfluorocarbon gas was formed by the electrochemical reactions between the F atoms in NdF63−, NdF52−, NdF4−, and Nd2F7− species that were most prone to undergo electrophilic reactions and anodic carbon during the neodymium electrolysis process. By focusing on the complexities of the ionic structure, this study provides insights into the behavior of the LiF–NdF3 molten salt, highlighting its role in the development of neodymium electrolysis technologies.

Direct Analysis of Marine Dissolved Organic Matter Using LC-FT-ICR MS.

Marine dissolved organic matter (DOM) is an important component of the global carbon cycle, yet its intricate composition and the sea salt matrix pose major challenges for chemical analysis. We introduce a direct injection, reversed-phase liquid chromatography ultrahigh resolution mass spectrometry approach to analyze marine DOM without the need for solid-phase extraction. Effective separation of salt and DOM is achieved with a large chromatographic column and an extended isocratic aqueous step. Postcolumn dilution of the sample flow with buffer-free solvents and implementing a counter gradient reduced salt buildup in the ion source and resulted in excellent repeatability. With this method, over 5,500 unique molecular formulas were detected from just 5.5 nmol carbon in 100 μL of filtered Arctic Ocean seawater. We observed a highly linear detector response for variable sample carbon concentrations and a high robustness against the salt matrix. Compared to solid-phase extracted DOM, our direct injection method demonstrated superior sensitivity for heteroatom-containing DOM. The direct analysis of seawater offers fast and simple sample preparation and avoids fractionation introduced by extraction. The method facilitates studies in environments, where only minimal sample volume is available e.g. in marine sediment pore water, ice cores, or permafrost soil solution. The small volume requirement also supports higher spatial (e.g., in soils) or temporal sample resolution (e.g., in culture experiments). Chromatographic separation adds further chemical information to molecular formulas, enhancing our understanding of marine biogeochemistry, chemodiversity, and ecological processes.

Chiral crystalline organic salts as supports of Pd nanoparticles forming selective heterogeneous catalysts for hydrogenation of nitroarenes

A novel catalyst based on Pd nanoparticles encapsulated in a chiral crystalline organic salt matrix is prepared from tetrasodium tetrakis(4-sulfonatophenyl)methane and tetrakis[4-(S)-prolinamidophenyl]methane in water at room temperature under hydrogen atmosphere. The hydrogenation of p-nitrobenzaldehyde over this catalyst stalls at the stage of p-aminobenzyl alcohol, whereas Pd/C brings the reduction further to p-toluidine.

Component Fluctuation Modulated Gelation Effect Enable Temperature Adaptability in Zinc‐Ion Batteries

AbstractThe active H2O and slow ion kinetics behavior deteriorate the performance of aqueous zinc‐ion batteries at a wide temperature range, even in hydrogel electrolyte. Herein, a component fluctuation modulated gelation effect is applied to optimize Zn2+ solvation structure, realizing a balance between H2O activity limitation and Zn2+ kinetics retention. The as‐prepared hydrogel electrolyte via in situ copolymerization of [2‐(methacryloyloxy)ethyl] dimethyl‐(3‐sulfopropyl) and acrylamide in the electrolyte salt matrix facilitates stable overall performance at both normal and low temperatures. Theoretical calculations and experimental results attest that polymer functional groups exhibit a higher efficacy in substituting bound water in the Zn2+ solvated shell with the polymer content increasement, thereby alleviating water‐associated parasitic reactions. Furthermore, the hydrogel with abundant zwitterionic groups not only interacts with H2O to limit hydrolysis, but also constructs separated ionic migration channels to promote uniform and fast Zn2+ transport. As a result, the hydrogel electrolytes promote stable Zn2+ plating/stripping behaviors over 1050 h and 3000 h at 25 and −20 °C, respectively. The full batteries achieve a capacity retention of 98.8% over 2000 cycles at 25 °C and stably cycle for 600 times at −20 °C. This work yields novel insights into the development and design of hydrogel electrolytes.

Rapid detection of per- and polyfluoroalkyl substances (PFAS) using paper spray-based mass spectrometry

Traditional PFAS analysis by mass spectrometry (MS) is time-consuming, as laborious sample preparation (e.g., extraction and desalting) is necessary. Herein, we report fast detection of PFAS by paper spray (PS)-based MS techniques, which employs a triangular-shaped filter paper for sample loading and ionization (≤ 3 min per sample). In this study, PS-MS was first used for direct PFAS analysis of drinking water, tap water, and wastewater. Interestingly, food package paper materials can be directly cut and examined with PS-MS for possible PFAS contamination. For samples containing salt matrices which would suppress PFAS ion signal, desalting paper spray mass spectrometry (DPS-MS), was shown to be capable of rapidly desalting, ionizing and detecting PFAS species such as per-fluorooctanoic acid (PFOA) and per-fluorosulphonic acid (PFOS). The retention of PFAS on paper substrate while salts being washed away by water is likely due to hydrophilic interaction between the PFAS polar head (e.g., carboxylic acid, sulfonic acid) with the polar filter paper cellulose surface. The DPS-MS method is highly sensitive (limits of detection:1.2–4.5 ppt) and can be applicable for directly analyzing soil extract and soil samples. These results suggest the high potential of PS-MS and the related DPS-MS technique in real-world environmental analysis of PFAS.

Installation of synergetic binding sites in β-Cyclodextrin-Bipyridine ionic liquid based magnetic sorbent for simultaneous removal of anionic PFAS and Cr (Ⅵ) in water matrix

Herein, we develop a versatile strategy for developing a Fe3O4-NH-β-CD-BP ILs based sorbent by installing synergistic bonding sites for simultaneous removal of per- and polyfluoroalkyl substances (PFASs) and heavy metals from contaminated water. This sorbent with its quaternary ammonium cation achieved remarkable removal efficiency (∼99 %)for both short and long chain anionic PFASs in pure water as compared to previous β-CD based materials. Moreover, when subjected to a challenging metal salt matrix, the adsorbents revealed that long-chain PFASs primarily relied on electrostatic and hydrophobic interactions, while short-chain PFASs depended solely on electrostatic attractions. The results indicate that the sorbent exhibits outstanding adsorption capacities for PFCAs, PFSAs and Cr (VI) coupled with fast adsorption kinetics featuring equilibrium times 5, 4 and 2 h, respectively. The simultaneous removal of PFOA, PFOS and Cr (VI) in multi-component systems (electroplating plant wastewater) was also determined due to their dual sites rendered by cationic and β-CD groups. The adsorption of PFCAs and Cr (VI) was significantly influenced by the initial pH compared to the sorption of PFSAs. Additionally, the viologen based sorbent also showed better photocatalytic hydrogen evolution activity. In summary, these results revealed the outstanding adsorption capacity and convenient regeneration process make the adsorbent as a promising candidate for efficient and rapid removal of PFASs from other pollutants.

Trapping of heavy metal ions from electroplating wastewater with phosphorylated double-shelled hollow spheres

The mesoporous multi-shelled hollow structures are promising for trapping of non-degradable heavy metal ions in wastewater but difficult to synthesize. We successfully demonstrated a simple strategy for the construction of mesopore windows on double-shelled α-Fe2O3 hollow spheres. A step-by-step proof of concept synthesis mechanism has been revealed by using mainly electron microscopy and thermogravimetric analysis. We proved that mesopore windows are indispensable to realize the complete surface coverage of phosphonate ligands on α-Fe2O3 double-shelled hollow spheres. The phosphonic groups inherently coordinated with Ni(II) and Cu(II) ions and formed complexes of high stability. Importantly, owing to the structural merits, the phosphorylated double-shelled hollow spheres selectively removes Ni(II) and Cu(II) at wider sample pH range with a high capacity of 380 mg g−1 and 410 mg g−1, respectively. In addition, no significant decrease in the removal efficiency was observed under high salt matrix. For electroplating industry wastewater, the novel structure performs simultaneous Ni(II) and Cu(II) removal, thus producing effluent of stable quality that meets local discharge regulations.

Cycling Stability of Calcium-Impregnated Vermiculite in Open Reactor Used as a Thermochemical Storage Material

Recent research into thermochemical storage (TCS) materials has highlighted their promising potential for seasonal building heating, through energy capture and release during dehydration and hydration cycling. A common TCS material used throughout this investigation was calcium chloride (CaCl2)-impregnated vermiculite-based salt in matrix (SIM). This material was assessed for its robustness during charging and discharging cycles to assess its behavior and in terms of energy stability and chemical stability; the results of which showed consistent volumetric energy density and maximum temperature changes over seven cycles. The calcium SIM did, however, show a decline in leachable Ca content, which was presumed to be a result of stabilization within the vermiculite, and chloride concentration showed little change over the course of the study. Real-time visualization using a high-resolution microscope of calcium SIM particles showed a salt phase change and migration of liquid salt into the valleys of the lamella. A novel cobalt chloride (CoCl2) SIM was used to visualize the hydration path across the particle, through distinct color changes depending on hydration state. The results indicated that the topography of the vermiculite played a significant role in the passive hydration modeling.

Development and Characterization of a New Solid Polymer Electrolyte for Supercapacitor Device

In this study, solid polymer electrolytes (SPEs) are based on methylcellulose (MC) used as a polymer host and sodium iodide (NaI) as a dopant. The SPE films are developed using different contents of ethyl carbonate (EC) as a plasticizer to enhance their properties via a solution casting method. The surface morphology of SPE films is shown using polarized optical microscopy (POM), which indicates the existence of amorphous patches due to the plasticizing effect of EC. The creation of a complex between MC, NaI, and EC was confirmed by Fourier transform infrared (FTIR) spectra. A tiny amount of EC applied to the MC-NaI polymer salt matrix increases the number of charge carriers and improves ionic conductivity. The ionic conductivity of the generated polymer electrolytes is examined using electrochemical impedance spectroscopy (EIS). The high-ion conducting PE of 5.06 × 10−3 S·cm−1 was found with the mixture MC + 50 wt% NaI + 10 wt% EC (room temperature). The linear speed voltammetry (LSV) test shows that the optimized polymer electrolyte can withstand decomposition up to 2.5 V. The optimized sample transmission numbers were calculated using a TNM (transference number measurement) approach, and the results show that 99% of the ions contribute to the conductivity, compared to only 1% of the electrons. A solid-state electrical double-layer capacitor (EDLC) was fabricated using the highest ion-conductive polymer electrolyte and graphene oxide (GO)-based electrodes. The galvanostatic charge-discharge (GCD) technique was performed, and the GCD graph shows the behavior of an ideal capacitor with a less Faradic process and a low ESR value. The GO-based cell’s columbic efficiency is 100%, and the system delivers the charge for a long duration. The EDLC cell demonstrates outstanding cyclability. The specific capacitance of the EDLC cell incorporated with MC + 50 wt. % NaI + 10 wt. % EC was found to be 154.66 F/g.

Comprehensive evaluation of matrix effect in the detection of Zn, Cd, Ni, Cu, Cr and Pb by solution cathode glow discharge optical emission spectrometry

Herein, the effect of different salt matrices on the signals of Zn, Cd, Ni, Cu, Cr, and Pb using solution cathode glow discharge optical emission spectrometry (SCGD-OES), was discussed at length. The cation interference test covered sodium, potassium, magnesium and calcium ions, while the anion interference test covered chloride and sulfate ions. Overall, the order of interference levels for the four cations was: Na+≈K+>Mg2+≈Ca2+. The emission of most elements was inhibited at Na+/K+/Mg2+/Ca2+ concentration exceeding 200 mg L-1. The impact of the two anions is not measurably different and almost no interference occurred when anion content reaching 200 mg L-1. The spectral interference caused by Na+ and K+ was also much greater than that of Mg2+ and Ca2+, which was reflected in the diminution of spectral bands of the two main molecules (OH and N2). The role of formic acid (HCOOH) has been reassessed at a salinity of 200 mg L-1 Na+. HCOOH was found to play a positive role on volatile species forming metals such as Pb, regardless of the presence of sodium salts. For elements (Cr) that are hard to evaporate and stimulate, HCOOH exhibited a strong inhibitory effect, possibly due to exacerbating the deterioration of the excitation state. For other transition metal elements in the fourth period, e.g., Zn, HCOOH demonstrated minor effects.

Polyoxometalates from gases: Mineral-inspired synthesis and characterization of novel compounds containing [M⊂Cu12O8(AsO4)8]q- polyoxocuprate clusters (M = Ti(IV), Bi(III))

A novel type of polyoxocuprate (POCu) clusters, [M⊂Cu12O8(AsO4)8]q- (M = Ti(IV), Bi(III)), with a cubooctahedral arrangement of Cu2+ cations, have been prepared by chemical vapor transport reactions (CVT) using the methodology inspired by mineralogical discoveries at volcanic fumaroles of the Tolbachik volcano (Kamchatka peninsula, Russia). Three new compounds, Na21Cl6F[TiF6][TiCu12O8(AsO4)8] (1), Na18Cl6[TiCu12O8(AsO4)8] (2), and Na18Cl5[BiCu12O8(AsO4)8] (3), prepared under low-vacuum conditions, contain the {[M⊂Cu12O8](AsO4)8} (M = Ti4+, Fe3+) clusters with a Keggin-ion-like cubooctahedral arrangement of Cu2+ cations encapsulating Mn+ cations strikingly similar to the {[Pd13O8]L8]q- polyoxoanions observed in polyoxopalladates. The packing modes of clusters in different structures are different, with the structures of 1 and 3 based upon cubic-close-packing and hexagonal-close-packing arrangements, respectively. The packing of clusters in 2 is rather complex that results in its extreme structural complexity with the amount of Shannon structural information per unit cell exceeding 3000 bits. In the title compounds, the POCu clusters are embedded into salt matrices and therefore can be considered as an inverse analogue of salt-inclusion compounds, i.e., as inclusion-in-salt compounds. The successful synthesis of new types of POCu clusters using the CVT techniques opens up a new synthetic pathway for the exploration of polyoxocuprates with promising interesting structures and physical properties.

Studies on a novel microporous electrospun poly(vinyl alcohol)‐based polymer electrolyte membranes for high‐performance battery applications

AbstractINTRODUCTIONSolid polymer blend electrolytes are scientifically interesting promising materials as electrolytes in advanced solid state electrochemical devices applications such as batteries, electrochemical display devices, smart windows, etc. The solid polymer blend electrolyte has several advantages including high energy density, a solvent free condition, structural stability, light weight, leak proof, good electrode electrolyte contact, ease of fabrication, easy processability and good mechanical properties.OBJECTIVESThe present research work deals with the study of composition and conductivity behavior of polymer blend electrolyte complex membranes based on PVA and PVP complexed with different weight percent KClO4 salt, prepared by electrospinning technique. The resultant polymer blend electrolytes have been characterized by XRD, FTIR and AC conductivity studies.METHODSPorous PVA based nanofiber membranes were prepared using a typical electrospinning technique with a horizontal arrangement. A stainless steel needle (24 G, outer diameter: 0.50 mm, inner diameter: 0.35 mm) was connected to an electrode of a high voltage power supply (Spellman, model CZE1000R) which could generate positive DC voltages up to 30 kV and a grounded stainless steel plate was placed at 10 cm distance from the needle tip to collect the nanofiber membranes.RESULTS AND DISCUSSIONA novel electrospun polymer electrolyte membranes comprising a blend of poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) containing various concentrations of potassium perchlorate KClO4 salt are prepared using electrospinning technique. The structure and complexation of the polymer electrolyte membranes have been confirmed from X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectral studies. The ac conductivity studies are performed to measure the ionic conductivity of the polymer electrolyte complex systems in the temperature range 298‐353 K and it is also found that the temperature dependence ionic conductivity data seems to follows the Arrhenius relation. The influence of complex membranes composition on the ionic conductivity has been discussed. The maximum ionic conductivity value is obtained to be 9.1×10−4 S cm−1 at 298 K for PVA‐PVP‐KClO4 (50‐35‐15) polymer system with 15 wt.% KClO4 salt. Scanning electron microscopy studies have been performed and reported.CONCLUSIONSFree standing, flexible complex polymer electrolyte membranes based on various compositions of PVA‐PVP‐KClO4 have been prepared. The presence of amorphous regions due to complexation of polymer salt matrices has been confirmed from XRD and FTIR analysis. The maximum value of ionic conductivity has been obtained to be 9.1 × 10−4 S cm−1 at 298 K for PVA‐PVP‐KClO4 (50‐35‐15) complex polymer electrolyte system with 15 wt.% KClO4. The excellent performance, such as high values of ionic conductivity, of polymer blend electrolyte membranes suggest that the membranes can be used as the best candidate for high performance solid state batteries.

Thermally Conductive Molten Salt for Thermal Energy Storage: Synergistic Effect of a Hybrid Graphite-Graphene Nanoplatelet Filler.

Renewable energy technologies depend, to a large extent, on the efficiency of thermal energy storage (TES) devices. In such storage applications, molten salts constitute an attractive platform due to their thermal and environmentally friendly properties. However, the low thermal conductivity (TC) of these salts (<1W m-1 K-1) downgrades the storage kinetics. A commonly used method to enhance TC is the addition of highly conductive carbon-based fillers that form a composite material with molten salt. However, even that enhancement is rather limited (<9W m-1 K-1). In this study, the partial exfoliation of graphite to graphene nanoplatelets (GnP) in a molten salt matrix is explored as a means to address this problem. A novel approach of hybrid filler formation directly in the molten salt is used to produce graphite-GnP-salt hybrid composite material. The good dispersion quality of the fillers in the salt matrix facilitates bridging between large graphite particles by the smaller GnP particles, resulting in the formation of a thermally conductive network. The thermal conductivity of the hybrid composite (up to 44W m-1 K-1) is thus enhanced by two orders of magnitude versus that of the pristine salt (0.64W m-1 K-1).

Optical, vibrational, electrical, and electrochemical studies of new plasticized methylcellulose‐based solid polymer electrolytes for supercapacitor application

AbstractIn this work, new plasticized solid polymer electrolytes (SPEs) are developed using MC (methylcellulose) as a polymer host, and sodium iodide (NaI) as a dopant via the solution casting method. Ethyl carbonate (EC) is used as a plasticizing agent to improve the properties of the SPEs. Polarized optical microscopy analysis reveals that the surface morphology of the MC‐NaI‐EC films contained porous amorphous regions owing to the presence of EC. The complex formation between MC, NaI, and EC is confirmed by Fourier‐transform infrared spectra. The addition of EC in the MC‐NaI polymer salt matrix enhances the electrochemical properties of the prepared films. The highest ionic conductivity of 5.06×10−3 S/cm is achieved for the composition: MC+50 wt. % NaI +10 wt. % EC. The linear sweep voltammetry test reveals that the optimal plasticized‐SPE can withstand up to 2.5 V. The ionic transference number analysis reveals that 99% of ions contribute to the total conductivity. The optimized SPE film and graphene oxide‐based electrodes are used to manufacture a solid‐state electrical double‐layer capacitor. The coulomb efficiency of the supercapacitor cell is 100%, and the specific capacitance of the supercapacitor is found to be 18.56 F/g utilizing impedance data at low frequency.

Anti-Fatigue Hydrogel Electrolyte for All-Flexible Zn-Ion Batteries.

Hydrogel electrolytes have been widely explored in Zn metal batteries for application in wearable electronics. While extensive studies have been conducted in optimizing the chemical structure and boosting the tensile elasticity, the mechanical stability of the hydrogel under repeated deformation is largely overlooked, leading to unsatisfactory performance at large cycling capacity. We systematically analyze the compressive fatigue-resistance properties of the hydrogel electrolyte, revealing the critical roles of the salts and copolymer matrix on crack initiation and propagation. We show that, on the premise of homogeneous Zn deposition, an improved anti-fatigue property is essential to achieve high-capacity Zn metal anodes. The optimal Zn(ClO4 )2 -polyacrylamide/chitosan hydrogel electrolyte (C-PAMCS) exhibits an unprecedented lifespan of 1500h for Zn//Zn cells at a current density of 10mA cm-2 and a high areal capacity of 10 mAh cm-2 . We exemplify the potential application of C-PAMCS in all-flexible Zn-ion batteries enabled by a flexible current collector based on Ag nanowires embedded elastomer. This work provides the rationale under hydrogel electrolyte engineering for developing high-performance Zn anodes and derived energy storage devices. This article is protected by copyright. All rights reserved.

Time-dependent Phosphorescence Color of Carbon Dots in Binary Salt Matrices through Activations by Structural Confinement and Defects for Dynamic Information Encryption.

The emergence of time-dependent phosphorescence color (TDPC) materials has taken information encryption to high-security levels. However, due to the only path of exciton transfer, it is almost impossible to obtain TDPC for chromophores with a single emission center. Theoretically, in inorganic-organic composites, the exciton transfer of organic chromophores depends on the inorganic structure. Here, we assign two structural effects to inorganic NaCl by metal (Mg2+ or Ca2+ or Ba2+ ) doping, which triggers the TDPC performance of carbon dots (CDs) with a single emission center. The resulting material is used for multi-level dynamic phosphorescence color 3D coding to achieve information encryption. The structural confinement activates the green phosphorescence of CDs; while the structural defect activates tunneling-related yellow phosphorescence. Such simply doped inorganic matrices can be synthesized using the periodic table of metal cations, endowing chromophores with tremendous control over TDPC properties. This demonstration extends the design view of dynamic luminescent materials.

Time‐dependent Phosphorescence Color of Carbon Dots in Binary Salt Matrices through Activations by Structural Confinement and Defects for Dynamic Information Encryption

AbstractThe emergence of time‐dependent phosphorescence color (TDPC) materials has taken information encryption to high‐security levels. However, due to the only path of exciton transfer, it is almost impossible to obtain TDPC for chromophores with a single emission center. Theoretically, in inorganic‐organic composites, the exciton transfer of organic chromophores depends on the inorganic structure. Here, we assign two structural effects to inorganic NaCl by metal (Mg2+ or Ca2+ or Ba2+) doping, which triggers the TDPC performance of carbon dots (CDs) with a single emission center. The resulting material is used for multi‐level dynamic phosphorescence color 3D coding to achieve information encryption. The structural confinement activates the green phosphorescence of CDs; while the structural defect activates tunneling‐related yellow phosphorescence. Such simply doped inorganic matrices can be synthesized using the periodic table of metal cations, endowing chromophores with tremendous control over TDPC properties. This demonstration extends the design view of dynamic luminescent materials.