Faraday Cage Research Articles

Employing a chelating agent as electrolyte additive with synergistic effects yields highly reversible zinc metal anodes.

Aqueous zinc ion batteries (AZIBs) have attracted sustained attention owing to their intrinsic safety and low cost. Unfortunately, the dendrite growth and parasitic side reactions of metallic zinc anodes severely degrade the cycling stability of the batteries and limit the practical application of AZIBs. In this work, calcium gluconate (CG), a chelating agent, as a novel electrolyte additive was introduced to tackle the thorny issue of zinc anodes in a 2 M ZnSO4 electrolyte by the synergistic effects of gluconate (GA-) anions and Ca2+ cations. Experimental characterization and computational simulations confirmed that the incorporation of GA- can not only mitigate the precipitation of Ca2+ ions, but also affect the primary solvation shell (PSS) of Zn2+ and modulate the electrode/electrolyte interfacial reaction, thereby inhibiting side reactions. Besides, trace amounts of Ca2+ cations can preferentially adsorb on the surface of the zinc anode tip, forming an electrostatic shielding shell that guides the uniform deposition of zinc ions. The Zn//Zn symmetric cells achieved a remarkably prolonged cycling lifespan ranging from 174 h to 3745 h at 6.37 mA cm-2 and 2.88 mA h cm-2 with an ultrahigh cumulative plating capacity (CPC) of about 11 900 mA h cm-2. Even at a higher current density of 5 mA cm-2 and an areal specific capacity of 5 mA h cm-2, Zn//Zn cells with the CG additive cycled for 248 h, about 5 times better than that without the CG additive. These results pave the way for the exploitation of new electrolyte additives with synergistic effects in AZIBs.

Barbital-derived chelating ligands for interface regulation and stabilization of Zn metal anodes for aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) have inherent merits, such as a low price, good safety and high volumetric capacity, and have promising potential for widespread applications. However, the unexpected issues posed by both water-induced side reactions and the uncontrollable growth of zinc dendrites on the zinc anode-electrolyte interface have significantly hindered the widespread application of AZIBs. In this work, barbital (Bb), which has two amide groups, was introduced into a ZnSO4 electrolyte to create a Bb@ZnSO4 electrolyte. The hydrolysis of the amide groups resulted in the formation of strong polar groups (carboxyl and amino), which could efficiently anchor zinc ions. Specifically, through the derivation of Bb, it was possible to adjust the Zn2+ solvation structure, decreasing the coordinated active SO42-/H2O and promoting the anchoring of these species on the surface of the zinc anode. This process provided electrostatic shielding and isolates the SO42-/H2O, demonstrating an interface regulating effect and synergistic solvation. Therefore, Bb could mitigate electrochemical corrosion and facilitate dendrite-free homogeneous zinc deposition. As a consequence, the assembled asymmetric Zn∥V2O5 full cell utilizing the Bb@ZnSO4 electrolyte showed highest specific capacities of 294.9 and 92.7 mA h g-1 at 0.1 and 1 A g-1, much higher than the Zn∥V2O5 full cell with the ZnSO4 electrolyte, which delivered specific capacities of 161.1 and 3.0 mA h g-1 at the same current densities. These findings promise to realize the practical application of Bb as an efficient additive in high-performance AZIBs.

Structural Design of an Electrostatic Shield at $-$600 kV for the MITICA Beam Source

Structural Design of an Electrostatic Shield at $-$600 kV for the MITICA Beam Source

Enhanced electrostatic shielding effect through incorporation of trace amounts of highly chelating anions for establishing a more stable electric double layer

IDHA anions with strong chelating capabilities participate in the solvation shell of Zn2+ and Na+. This interaction between IDHA anions and Na+ serves to stabilize the solvated sheath, thereby enhancing the electrostatic shielding effect of Na+.

Ultra-stability and high output performance of a sliding mode triboelectric nanogenerator achieved by an asymmetric electrode structure design

A new type of sliding-TENG with asymmetric electrode design achieves high output performance and ultra-stability by the balance of electrostatic shielding and charge accumulation for providing power supply to some electrical devices.

Deposition of uniform diamond films on three dimensional Si spheres by using faraday cage in MPCVD reactor

Deposition of a consistent diamond coating on intricate surfaces has historically posed a difficulty. This article presents the advancement in research on depositing a uniform diamond coating on three-dimensional (3D) silicon spheres, utilizing a faraday cage within a microwave plasma chemical vapor deposition (MPCVD) reactor. A self-consistent three-dimensional multi-physics field model has been established for simulating the microwave electric field and plasma inside a reactor with or without a faraday cage. Results indicate the cage effectively reduces the discharge at the top of the silicon sphere and improves uniformity of the distribution of the microwave electric field and plasma electron density on the sphere's surface. MPCVD trials have demonstrated that a powerful discharge takes place at the apex of the silicon sphere resulting in an excessive thermal gradient if the cage is not added. The apex of the silicon sphere is covered with a blend of diamond and graphite phases. Due to the excessive internal stress of the coating, approximately 50 % of the samples experience coating detachment. After the addition of the cage, the strong discharge is transferred to the top of the cage, effectively suppressing the microwave electric field and plasma inside the cage. Improved quality, reduced internal stress, and enhanced uniformity of the polycrystalline diamond coating are achievable on the silicon spheres within the cage. Moreover, this technique offers a novel approach to coat diamond on complex 3D geometries.

Quality evaluation of strawberries coated with water-in-oil based emulsion using an advanced electrostatic spray coating system.

In this study, the impact of formulated emulsion was studied on strawberries which were coated using dip and electrostatic spray coatingmethods. The coated strawberries were kept at room temperature for a period of 12days. A significant level of chargeability of w/o emulsion was achieved in terms of charge-to-mass ratio of 2.81 mC/kg at an applied high voltage of 2.0kV, applied air pressure of 0.3MPa, and liquid flow rate of 33.6ml/min. The distance of 170mm from the nozzle tip to Faraday cage was maintained during the measurements. As compared to uncoated and dip coated strawberries, the water-in-oil based electrostatically charged sprays considerably (p < 0.05) reduced theweight loss, decay rate, pH, titrable acidity, TSS, and antioxidant activity. In both the cases, i.e. strawberries coated with dip and electrostatic spraycoating methods, the same weight loss was observed, however, there was a considerably less weight loss as compared to uncoated samples. The textures of the uncoated (9.02 N) and dip coated (12.58 N) samples were significantly different from the electrostatic spray coated (15.85 N) samples. Since, the coating formulation had no impact on the sensory attributes, thesamples were considered as acceptable at the end of the storage. Furthermore, compared to uncoated, water-in-oil based electrostatically charged spray coating was more effective at delaying the decay by 12days.

Dendrite-free zinc anode enabled by bifunctional additive coupling electrostatic shielding and zincophilic leveling

The development of aqueous zinc-based batteries is hindered by the dendrite formation and side reactions. To address the issues, a novel bifunctional sodium citrate (Na3CA) electrolyte additive is developed, in which sodium ion forms an electrostatic shielding layer on the zinc surface to suppress the growth of zinc dendrites, while zincophilic citrate ion replaces water molecules in the solvent shell through leveling effect to reduce side reactions and adsorb onto the electrode surface to promote the uniform zinc deposition. Results show that in the symmetrical tests, the addition of Na3CA additive decreases the nucleation overpotential from 64.3 mV to 31.6 mV, enabling the battery to be stably cycled for more than 3500 h at the current density of 0.5 mA cm−2, which is 14 times higher than that with the traditional electrolyte. In the half-battery test, the Na3CA additive significantly improves the reversibility of the zinc anode with the average coulombic efficiency increasing from 87 % to 95 %. Full battery test shows that after 500 cycles, the capacity retention rate of the battery with Na3CA additive is 1.6 times that of the traditional battery. This work offers a facile and effective strategy of designing bifunctional electrolyte additive to achieve high-performance aqueous zinc-based batteries.

Multi-Purpose Structure-Integrated Zinc-Polyiodide Hybrid Flow Battery As Sustainable Energy Storage System for Extraterrestrial Environments

For the energy supply of spacecrafts, such as space stations, satellites or orbiters, primarily solar power is used, which conversion, however, is subject to constant fluctuations due to rotational and orbital movements. In order to secure energy security for technical operations, the maintenance of scientific test series as well as life-support measures even during dark phases, various types of batteries such as nickel-hydrogen or nickel-cadmium batteries have been used as buffer storage over the years. However, due to the isolated locations in which they are used, energy storage systems for space applications must have a particularly long service life and operational reliability in order to be able to reduce resource-intensive replacement missions as well as hazards to people and technology.Since the battery systems used in space applications have in some cases shown significant deficits in these areas, a novel storage concept was developed in the "SpaceFlow" project, which was awarded third place in the europewide idea competition INNOspace Masters DLR Challenge, using the particularly safe and durable flow battery technology. The energy storage concept is based on the space-efficient integration of pressure-stable yet flexible flow battery cells into the supporting structure of spacecraft. In this way, in addition to energy storage as the primary task, other functions such as mechanical stiffening of the modules, support of thermal management or absorption of radiation can be realized.The "SpaceFlow"battery is realized as a zinc-polyiodide hybrid flow battery, which achieved incomparably high energy densities in laboratory tests. An energy density of 167 Wh/l was demonstrated and the potential to increase the energy density even up to 350 Wh/l was shown. The currently most widely used all-vanadium flow battery achieves energy densities of about 30 Wh/l. To optimize the cell chemistry zinc-polyiodide, various additives will be tested in the project. For a controlled formation of dendrites, for example, polyethylene glycol, methanesulfonic acid, chromium ions and, in general, alcohols, especially ethanol, could be added to the electrolytes as additives. In organic compounds, the presence of hydroxyl groups is an important factor in stabilizing the Zn ions. The deposition is also influenced by these. The search for additional alcohol and ether compounds offers the potential to find new additives. Chromium ions provide electrostatic shielding during zinc deposition, inhibiting dendrite growth.The iodine side (cathode) can be optimized mainly by improving the solubility of I2 in water. Stabilization of I2 without the binding of I- provides more free I-, which can react and help increase the capacity of the battery. Bromine ions or polyvinylpyrrolidone can be used to stabilize I2. Other additives such as KI and NH4Cl can be used for improved conductivity. Another approach is to improve diffusion at the cathode. For this purpose, a molybdenum sulfide coating can be applied, which improves the reaction rate with only a slight overpotential.The talk will present the novel storage concept and achievable functionalities as well as the latest project results of the flow cell design development and the design of a zinc polyiodide electrolyte, which must not be hazardous to humans and and at the same time must have a high energy density, to meet the requirements of space applications.

Spectral Analysis of Anomalous Capacitance Measurements in Interleaving Structures: Study of Frequency Distribution in Photomultipliers

This study presents experimental results on capacitance fluctuations in several devices located within an interleaving structure. Specifically, it examines the behavior of the capacitance between the anode and cathode of a photomultiplier, comparing it with the characteristics of the ultra-stable capacitor analyzed in via measurements inside and outside a modified Faraday cage. The results cover spectral and correlation analyses both inside and outside the box, confirming differences in the spectrum using the periodograms. In particular, the confidence intervals for the mean capacitance values show significant changes between the two scenarios, from the inside to the outside of the enclosure. In the case of the ultra-stable capacitor, there is an increase from 0.004 to 0.008 nF. On the other hand, a symmetry analysis is conducted for all measurements taken both outside and inside the modified Faraday cage. It is observed that in all cases, there is clear non-symmetric behavior in the data.

An inorganic-rich but LiF-free interphase for fast charging and long cycle life lithium metal batteries

Li metal batteries using Li metal as negative electrode and LiNi1-x-yMnxCoyO2 as positive electrode represent the next generation high-energy batteries. A major challenge facing these batteries is finding electrolytes capable of forming good interphases. Conventionally, electrolyte is fluorinated to generate anion-derived LiF-rich interphases. However, their low ionic conductivities forbid fast-charging. Here, we use CsNO3 as a dual-functional additive to form stable interphases on both electrodes. Such strategy allows the use of 1,2-dimethoxyethane as the single solvent, promising superior ion transport and fast charging. LiNi1-x-yMnxCoyO2 is protected by the nitrate-derived species. On the Li metal side, large Cs+ has weak interactions with the solvent, leading to presence of anions in the solvation sheath and an anion-derived interphase. The interphase is surprisingly dominated by cesium bis(fluorosulfonyl)imide, a component not reported before. Its presence suggests that Cs+ is doing more than just electrostatic shielding as commonly believed. The interphase is free of LiF but still promises high performance as cells with high LiNi0.8Mn0.1Co0.1O2 loading (21 mg/cm2) and low N/P ratio (~2) can be cycled at 2C (~8 mA/cm2) with above 80% capacity retention after 200 cycles. These results suggest the role of LiF and Cs-containing additives need to be revisited.

Environmental stress-induced conformational transitions modulate foaming and gelation properties of glycosylated egg white proteins

Glycosylation induces covalent grafting, resulting in conformational shifts that modulate the functional properties of proteins. This study examines the effect of conformational changes on the foaming and gelation properties of d-xylose glycosylated egg white protein (G-EWP) under different pH, ionic strength, and temperature conditions. Glycosylation end-products content increases initially, then reduces with increasing temperature while negatively correlating with pH and NaCl concentration. Treatment with NaCl induces electrostatic shielding on the G-EWP surface, decreasing the absolute value of ζ-potential from 19.63 mV to 14.9 mV. Temperature promotes thermal denaturation and macromolecular aggregation of G-EWP, increasing the particle size significantly from 523.9 nm to 4458.92 nm. Spectroscopic and protein structure analyses show that different environmental stresses alter the conformational structure of G-EWP, causing the rearrangement of amino acid residues. High temperature exerts a more pronounced effect on the secondary structure of G-EWP compared to variations in pH and NaCl, where the α-helices decline from 40.37% to 7.83% and the β-turns content increases from 19.30% to 39.57%. Reheating at 60 °C and acid treatment significantly increase the gel hardness, and the foaming capacity of G-EWP declines gradually with increasing pH and NaCl concentration, but improves with increasing temperature. Correlation analysis reveals that the molecular flexibility, β-sheet and β-turns effectiveness regulate the foaming capacity, and the charge variation positively modulates the gel properties of G-EWP.This study provides insight into regulating the functional properties of G-EWP effectively in industrial applications.

Diagnosing the Electrostatic Shielding Mechanism for Dendrite Suppression in Aqueous Zinc Batteries.

Aqueous zinc electrolytes offer the potential for cheaper rechargeable batteries due to their safe compatibility with the high capacity metal anode; yet, they are stymied by irregular zinc deposition and consequent dendrite growth. Suppressing dendrite formation by tailoring the electrolyte is a proven approach from lithium batteries; yet, the underlying mechanistic understanding that guides such tailoring does not necessarily directly translate from one system to the other. Here, it is shown that the electrostatic shielding mechanism, a fundamental concept in electrolyte engineering for stable metal anodes, has different consequences for the plating morphology in aqueous zinc batteries. Operando electrochemical transmission electron microscopy is used to directly observe the zinc nucleation and growth under different electrolyte compositions and reveal that electrostatic shielding additive suppresses dendrites by inhibiting secondary zinc nucleation along the (100) edges of existing primary deposits and encouraging preferential deposition on the (002) faces, leading to a dense and block-like zinc morphology. The strong influence of the crystallography of Zn on the electrostatic shielding mechanism is further confirmed with Zn||Ti cells and density functional theory modeling. This work demonstrates the importance of considering the unique aspects of the aqueous zinc battery system when using concepts from other battery chemistries.

Interfacial modulation via cationic electrostatic shielding effect for reversible and durable Zn anodes in hydrogel electrolytes

Although metallic Zn has been considered as a promising anode material in aqueous energy storage systems owing to its high theoretical capacity and intrinsic security, its practical applications are limited by dendrite growth and side reactions at the interface. To address these challenges, here we propose a cationic electrostatic shieling strategy by incorporating choline (Ch+) cations in hydrogel electrolyte (denoted as gel-ChCl electrolyte) to optimize the electrolyte-electrode interface. Theoretical and experimental findings reveal that the Ch+ cations preferentially adsorb on the Zn surface to create an electrostatic shielding layer, which functions dual effects, i.e., redistributing interfacial Zn2+ ions for the uniform deposition and fabricating water-poor interface for the inhibited side reactions. With this strategy, dendrite-free Zn anodes with high plating/stripping reversibility are realized in Zn//Zn and Zn//Cu cells for long-term lifespan and high average coulombic efficiency, respectively. More impressively, the Zn-ion hybrid capacitors (ZHCs) optimized by the gel-ChCl electrolyte deliver favorable flexibility, excellent cyclability (82.6% capacity retention after 40,000 cycles), and energy-storage applications. This work proposes a facile cationic electrostatic shielding strategy to modulate the electrolyte-electrode interface for reaching dendrite-free Zn anodes, which is favorable for advanced flexible ZHCs and beyond.

Electrolyte Additives for Stable Zn Anodes.

Zn-ion batteries are regarded as the most promising batteries for next-generation, large-scale energy storage because of their low cost, high safety, and eco-friendly nature. The use of aqueous electrolytes results in poor reversibility and leads to many challenges related to the Zn anode. Electrolyte additives can effectively address many such challenges, including dendrite growth and corrosion. This review provides a comprehensive introduction to the major challenges in and current strategies used for Zn anode protection. In particular, an in-depth and fundamental understanding is provided of the various functions of electrolyte additives, including electrostatic shielding, adsorption, in situ solid electrolyte interphase formation, enhancing water stability, and surface texture regulation. Potential future research directions for electrolyte additives used in aqueous Zn-ion batteries are also discussed.

Efficient adsorption of chloroquine phosphate by a novel sodium alginate/tannic acid double-network hydrogel in a wide pH range

In this work, a novel double-network composite hydrogel (SA/TA), composed of sodium alginate (SA) and tannic acid (TA), was designed and fabricated by a successive cross-linking method using Ti(IV) and Ca(II) as crosslinkers. SA/TA exhibited reinforced mechanical strength and anti-swelling properties because of the double-network structure. SA/TA was used as an adsorbent for removal of a popular antiviral drug, chloroquine phosphate (CQ), in water. The adsorption performance of SA/TA was systematically investigated, to study various effects including those of TA mass content, solution pH, adsorption time, and initial CQ concentration. Adsorption was also examined in presence of inorganic and organic coexisting substances commonly found in wastewater, and under different actual water samples. Batch experimental results indicated that SA/TA could maintain higher and more stable CQ uptakes within a wide solution pH range from 3.0 to 10.0, compared to its precursor, SA hydrogel, owing to the addition of TA-Ti(IV) coordination network. The maximum experimental CQ uptake exhibited by the 1:1 (by wt) SA/TA (SA/TA2) was as high as 0.699 mmol/g at the initial pH of 9.0. A high concentration of coexisting NaCl evidently reduced the CQ uptakes of SA/TA2 due to the electrostatic shielding effect, moreover, divalent cations including Ca(II) and Mg(II) also inhibited the adsorption of CQ due to competitive adsorption. However, humic acid had little effect on this adsorption. Considering the apparent adsorption performance, the aforementioned effects of various factors and the spectroscopic characterizations, multi-interactions are suggested for adsorption including chelation, electrostatic interactions, π-π electron donor-acceptor interaction and hydrogen bonding. SA/TA showed a slight loss in adsorption capacity toward CQ and sustained physicochemical structural stability, even after six adsorption–desorption cycles. In addition to CQ, SA/TA could be efficiently used for adsorption of two other antivirus drugs, namely, hydroxychloroquine sulfate and oseltamivir phosphate. This work provides an effective strategy for the design and fabrication of novel adsorbents that can effectively adsorb antiviral drugs over a wide pH range.

Strong gelation capacity of a pectin-like polysaccharide in the presence of K+ ion

In the present study, a pectin-like apple polysaccharide (AP) obtained by metal precipitation technique was demonstrated to show strong gelling capacity in the presence of K+ ion upon cooling. Increasing amount of K+ addition monotonically promoted the gelation of AP, as characterized by the increased gelation temperature (Tgel), gel melting temperature (Tmelt) and the gel strength. Compared with K+ ion, Na+ was unable to induce AP gelation even at high ionic concentrations, but other monovalent cations (Rb+, Cs+) can induce the gelation as in the case of K+ addition. At room temperature, the minimum cationic concentration as required to induce AP gelation followed the order of K+ ≈ Cr+ (8 mM) > Rb+ (3.5 mM), indicating that cationic radius (Na+ < K+ < Rb+ < Cs+) played a dominant role in inducing AP gelation, but other factors may also be involved. Finally, the gelation behavior of AP in the presence of K+ was explained as the suppressed intermolecular electrostatic repulsion between AP chains due to the strong electrostatic shielding effect of K+, which led to the formation of a gel network mediated by intermolecular hydrogen bonding. This reported gelation property may allow AP to find application as a new gelling polysaccharide.

Inverse shielding and mutual exclusion for PET-MR hybrid imaging concerning induced positronium hyperfine splits radiations

Prevalent PET imaging reconstructs 2γ-photon pairs emitted after an annihilation from para-positronium (p-Ps) and rejects 3γ events from ortho-positronium (o-Ps) as noises. The 3γ/2γ decay ratio is ~ 3/7 in human body theoretically but in fact significantly lower due to pick-off process, hence PET imaging quality is well controlled. In a PET-MR hybrid unit, the MR magnetic field alters positronium decay patterns through magnetic quenching: all o-Ps and excited p-Ps states are split into finer quantum states under strong magnetic field, thus transitions between some triplet and singlet finer states (mz = 0) were no longer forbidden, thus some o-Ps converts to p-Ps spontaneously by emitting hyperfine split (HFS) photons, which also drops 3γ/2γ ratio hence helps PET imaging quality. However, inverse magnetic quenching might also occur if any external source of HFS frequencies is nearby, thus many p-Ps convert to o-Ps by absorbing those HFS photons (induced HFS transitions). This will dramatically increase 3γ/2γ ratio and hence degrade PET imaging quality instantaneously. The HFS spectrum lies in a broad range of microwaves, from 0.02 to 200 GHz. To prevent inverse magnetic quenching, it is necessary to block external microwave sources outside the hybrid vault, by adding a thin metal layer at all directions of the vault. This could be achieved by adopting the metallic Faraday Cage, which was originally for MR shielding, with possible amendment if necessary. The frequencies of excitation pulses in MR imaging overlap with HFS spectrum, however, the chance for mutual interference during hybrid imaging is small, hence there seems no need to veto each other during hybrid scans.

Isolation of High-Molecular-Weight DNA for Long-Read Sequencing Using a High-Salt Gel Electroelution Trap.

Long-read sequencing technologies require high-molecular-weight (HMW) DNA of sufficient purity and integrity, which can be difficult to obtain from complex biological samples. We propose a method for purifying HMW DNA that takes advantage of the fact that DNA's electrophoretic mobility decreases in a high-ionic-strength environment. The method begins with the separation of HMW DNA from various impurities by electrophoresis in an agarose gel-filled channel. After sufficient separation, a high-salt gel block is placed ahead of the DNA band of interest, leaving a gap between the separating gel and the high-salt gel that serves as a reservoir for sample collection. The DNA is then electroeluted from the separating gel into the reservoir, where its migration slows due to electrostatic shielding of the DNA's negative charge by excess counterions from the high-salt gel. As a result, the reservoir accumulates HMW DNA of high purity and integrity, which can be easily collected and used for long-read sequencing and other demanding applications without additional desalting. The method is simple and inexpensive, yields sequencing-grade HMW DNA even from difficult plant and soil samples, and has the potential for automation and scalability.

Tailoring the solvation shells of dual metal ions for high-performance aqueous zinc ion batteries

For a long time, the issue of dendrites in neutral/mild electrolyte-based aqueous zinc-ion batteries (AZIBs) has been a matter of concern. The dendrites resulting from this problem lead to short-circuit faults and significantly reduce the cycle life, which is quite troublesome. Here, we induce uniform Zn deposition by utilizing the enhanced electrostatic shielding effect of a hybrid additive of Na2SO4 and EDTA. The limited tip-blocking effect of Na+ is due to the higher exchange reaction rate constant (kex) of water molecules in the solvation shell. The coordination of EDTA can provide a more stable solvation shell for Na+, ensuring a stronger blocking effect on Zn deposition at the tip. This enhanced electrostatic shielding effect effectively suppresses the growth of Zn dendrites. In addition, EDTA also enters the solvation shell of Zn2+ and displaces some coordinated water molecules, allowing for more reversible Zn plating/stripping without significant side reactions occurring at the Zn anode.