Electrostatic Shielding Effect Research Articles

A dynamic electrostatic shielding layer toward highly reversible Zn metal anode

Aqueous Zn-ion batteries (AZIBs) have gained considerable attention due to their inherent safety, cost-effectiveness, and environmental friendliness. However, their application in large-scale energy storage system is hindered by uncontrollable dendrite growth and severe side reactions at the electrode-electrolyte interface. To address these challenges, we propose the incorporation of trivalent yttrium (Y3+) ions in ZnSO4 electrolyte, which can form a cationic electrostatic shielding layer on the Zn anode to regulate the deposition behavior of Zn2+ ions. The inert Y3+ ions with a lower effective reduction potential will selectively adsorb on the active sites, facilitating uniform Zn deposition through a sustained dynamic electrostatic shielding effect. Moreover, the adsorbed Y3+ ions create a protective interface for the Zn anode, mitigating the corrosion reactions caused by water molecules. Consequently, the Zn//Zn cell with 0.1 M Y3+ ions demonstrates dendrite-free Zn plating/stripping over 2080 h at 5 mA cm−2, and the assembled Zn//NH4V4O10 cell delivers a high capacity retention of 89.6% after 2000 cycles at 5 A g−1. This work develops a new rare earth ion additive and confirms its sustained dynamic electrostatic shielding effect for dendrite-free Zn deposition, providing theoretical support and an exploration direction for further investigation of unexplored rare earth elements.

Efficient Suppression of Dendrites and Side Reactions by Strong Electrostatic Shielding Effect via the Additive of Rb2 SO4 for Anodes in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention due to their low cost and environmental friendliness. However, the rampant dendrite growth and severe side reactions during plating/stripping on the surface of zinc (Zn) anode hinder the practicability of AZIBs. Herein, an effective and non-toxic cationic electrolyte additive of Rb2 SO4 is proposed to address the issues. The large cation of Rb+ is preferentially adsorbed on the surface of Zn metal to induce a strong shielding effect for realizing the lateral deposition of Zn2+ ions along the Zn surface and isolating water from Zn metal to effectively inhibit side reactions. Consequently, the Zn||Zn symmetric cell with the addition of 1.5mm Rb2 SO4 can cycle more than 6000h at 0.5mA cm-2 /0.25 mAh cm-2 , which is 20 times longer than that without Rb2 SO4 . Besides, the Zn||Cu asymmetric cell with Rb2 SO4 achieves a very high average Coulombic efficiency of 99.16% up to 500 cycles. Moreover, the electrolyte with Rb2 SO4 well matches with the VO2 cathode, achieving high initial capacity of 412.7 mAh g-1 at 5 A g-1 and excellent cycling stability with a capacity retention of 71.6% at 5 A g-1 after 500 cycles for the Zn//VO2 full cell.

Evolutions of synergistic binding between konjac glucomannan and xanthan with high pyruvate group content induced by monovalent and divalent cation concentration

Synergistic interaction gels could be formed by synergistic type-A and type-B bindings between konjac glucomannan (KGM) and xanthan during cooling. Adding salt ions significantly altered those bindings and thus the gel-related properties. The results showed that adding NaCl or CaCl2 eliminated type-B binding due to an electrostatic shielding effect. Adding NaCl or CaCl2 (3 and 6 mM) enhanced type-A binding by neutralizing the negative charge of COOH and reducing the electrostatic repulsion among xanthan chains, as evidenced by an increase in the onset temperature of exotherm peak, the formation of more parallel multiple filaments, and an increase in aggregation structures (>1.0 nm) and gel hardness. When CaCl2 concentration was higher, Ca2+ bridged side-chain clusters into more complex structures, which would hardly participate in the formation of helical structures and weaken type-A binding. The results obtained are beneficial for the rational design and preparation of KGM/xanthan gels with synergistic interaction.

Phonon Polaritons: A New Paradigm for Light‐Controllable Heat Sources

AbstractPhotothermal applications, such as therapy, imaging, and catalysis, necessitate heat sources capable of generating high temperatures under mid‐infrared (mid‐IR) illumination. However, commonly used metal nanostructures suffer from low efficiency due to their high carrier concentrations, resulting in shallow surface heating and optical range restrictions. To overcome these limitations, this work proposes a novel approach employing materials that support phonon polaritons (PhPs) as a promising paradigm for light‐controllable heat sources. The theoretical demonstration reveals that hexagonal boron nitride (hBN) nanorods can produce up to 46 times more heat compared to plasmonic gold counterparts under resonant monochromatic light. This superior heating capability stems from the unique properties of PhPs, which enable stronger field confinement and deeper penetration within the nanostructure, leading to higher efficiency by circumventing the electrostatic shielding effect associated with plasmonic heating. Furthermore, this work demonstrates that the heating performance of hBN antennas can be optimized by manipulating their size, geometry, and material loss. Notably, the use of isotopically pure hBN can triple the heat power. These findings highlight the tremendous potential of hBN antennas as light‐controllable heat sources, opening up new possibilities for IR photothermal applications by harnessing materials that support PhPs.

Molecular mechanisms of pyrophosphate-mediated selective adsorption of Ni(II) by polyamine-grafted chitosan–wood flour composite from alkaline plating wastewater: EXAFS investigation and theoretical calculations

The efficient removal of complexed heavy metals (HMs) from alkaline electroless plating wastewater is still challenging. A polyamine-grafted chitosan–wood flour-based composite (ACS-AWF) was optimally synthesized. Its adsorption behavior toward Ni(II) in simulated pyrophosphate (PP, the main complextant)–Ni plating wastewater and underlying mechanisms were examined. PP considerably promoted Ni(II) adsorption by up to 108.1%, and the enhancement tolerated excess PP or other substances. Ni(II) adsorption by ACS-AWF was 1.38–∼10 times that of several commercial HM-favored resins in the same complexed system. According to the liquid solute species tracking, solid chemical characterizations (eg. synchrotron radiation X-ray adsorption spectroscopy), and theoretical calculations, it was found that Ni(II), primarily as NiP2O72−, could be captured by charge-assistant coordination with the surface polyamine. Then, the coadsorption of PP altered the interface properties via both electrostatic shielding and bridging effect, enhancing Ni(II)–amine coordination efficiency. A dinuclear multilayer coordination structure [-amine–Ni–PP–Ni–amine-] was proposed as the dominant Ni(II) binding mode in the presence of PP. Ni(II) and PP could be sequentially desorbed from ACS-AWF using gradient elution with ＞95.5% Ni(II) purity. ACS-AWF was then stably reused in five cycles (capacity loss ＜10%). These results may guide adsorbent design and application in HM purification and recycling from complexed wastewater.

Research on the shielding effect of the electrode frames in the electrostatic precipitator

ABSTRACT The electrostatic precipitator (ESP) plays an important role in the dust removal from the flue gas. Currently, the shielding effect of electrode frames seriously affects the electric field distribution and dust removal efficiency of ESPs. In order to explore the shielding effect and propose an improved measurement, an experimental setup with RS barbed electrodes and a 480 C type dust collector electrode plate was built to evaluate the corona discharge characteristics. The current density distribution on the surface of the collecting plate was tested on an ESP experimental setup. The effect of electrode frames on the current density distribution was also systematically investigated. The test results show that the current density distribution on the position that directly opposites the needle of RS corona discharge is much higher, on the contrary, the current density on the position that directly opposites the frames is almost zero. It indicates that the frames have a shielding effect on the corona discharge. Therefore, the dust collection efficiency is low in actual ESPs due to the dust escape route caused by the shielding effect. To solve the problem, a new ESP with a split-level frame arrangement was proposed. Implications: The conventional electrostatic precipitators are often affected by the electrostatic shielding effect, which leads to uneven charging. The particulate removal efficiency decreases and escape channels are very easy to form. In this study, effective measures were proposed to solve the electrostatic shielding of dust collector frames by studying their electrostatic shielding mechanism. The study provides theoretical support for the improvement of electrostatic precipitators, while improving the dust removal efficiency.

Nanocellulosic triboelectric materials with micro-mountain arrays for moisture-resisting wearable sensors

The pervasive wearable electronic devices are driving sensor innovation towards increased diversity and multifunctionality, to meet the needs of complex and varied environments. The accuracy of wearable sensors in detecting and feedback on stress is typically contingent upon the responsiveness of material structures, which can be easily perturbed by environmental humidity. In this study, one with excellent hydrophobicity and moisture resistance was developed, thereby effectively suppressing the electrostatic shielding effect caused by water ionization, while retaining the inherent ability of the material surface to generate and capture charges. In high-humidity environments (98 % RH), the self-powered sensor exhibited a full scale output retention rate of over 82.4 %, thus overcoming the limitations of sensor application in such conditions. This study provides new insight into high-performance sensing that is resistant to environmental interference, which is of great significance for the development and design of electronic skin, wearable electronic devices, and soft robotics.

Inhibiting polysulfide shuttling with a flexible “skin” for highly stable Lithium-Sulfur batteries

Ion electrokinetic regulation on separator is crucial for reducing polysulfide shuttling in lithium-sulfur (Li-S) batteries. Inspired by the electrostatic shielding effect, we implant a flexible “skin” composed of organic molecules (PDDA/PSS) with different charges anchored on carbon nanotubes (CNT), which act as a functional interlayer to prevent the shuttling of polysulfides. Systematic experiments and advanced theoretical calculations show that PDDA@CNT with positively charged amino groups not only provides adequate surface affinity to capture polysulfide anions, but also the highly conductive and high specific surface area CNT enables fast electron/ion migration and physical barrier. Consequently, the cell with PDDA@CNT/PP exhibits a high discharge capacity of 706 mAh g−1 and a favorable cycle stability of 1054 mAh g−1 after 250 cycles at 1C with high coulombic efficiency of 97%. This proof-of-concept work offers new perspectives on how to tailor the ionic behaviors of separators for high-energy Li-S batteries.

Synergistic structure of LiFeO2 and Fe2O3 layers with electrostatic shielding effect to suppress surface lattice oxygen release of Ni-rich cathode

The Ni-rich cathodes used for lithium-ion batteries (LIBs) suffer from severe surface side reactions, slow kinetics, and microcracks during long-term cycling. To address these problems, a dual-modified protective coating consisting of LiFeO2&Fe2O3 layers (denoted as LFO) was fabricated on the surface of the cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) by capturing the lithium impurities in the electrolyte solution using an electric field. The LiFeO2 layer acts as an ionic conductor, accelerating interfacial Li+ transport, and exhibits a synergistic effect with the bulk material during the charging/discharging process. The Fe2O3 layer, which contains abundant oxygen vacancies, acts as an electrostatic shielding layer and effectively inhibits the outward migration of Oα− (α < 2), thus improving the structural stability. Hence, the interface-protected NCM@LFO3 cathode showed excellent cycling stability (capacity retention of 82.4% after 600 cycles at 1 C) and even at a high cut-off voltage of 4.5 V (capacity retention of 88.9 % after 200 cycles at 1 C).

Sodium-potassium co-doped layered manganese dioxide cathode material for high performance aqueous zinc-ion batteries

Manganese dioxide with high operating voltage and satisfactory energy density have been identified as the promising cathode materials for aqueous zinc-ion batteries (AZIBs). However, the structural instability of manganese-based materials during the (dis)charging process limits their further development. Herein, sodium-potassium co-doped layered K0.37Na0.18MnO2·xH2O (KNMOH) are synthesized by a liquid-phase synthesis method at room temperature. The co-doping of Na+ and K+ stabilizes the layered structure, widens the layer spacing and has the effect of electrostatic shielding to facilitate the (de)intercalation of Zn2+. Benefiting from the stable structure and nanoscale size, the flower-like KNMOH cathode maintained a high specific capacity of 239.1 mAh·g−1 after 700 cycles at 500 mA·g−1. Simultaneously, this work firstly reveals that the presence of K8(SO4)(SO3OH)6 suppressed the generation of Zn4SO4(OH)6·0.5H2O, resulting in more free Zn2+ and high reversibility. This co-doped design of bimetallic ions insertion enhances the electrochemical performance and provides a new idea for the improvement of the manganese-based cathode materials for AZIBs.

Ammonium and Tetraalkylammonium Salts as Additives for Li Metal Electrodes

Lithium metal batteries are considered a promising technology to implement high energy density rechargeable systems beyond lithium-ion batteries. However, the development of dendritic morphology is the basis of safety and performance issues and represents the main limiting factor for using lithium anodes in commercial rechargeable batteries. In this study, the electrochemical behaviour of Li metal has been investigated in organic carbonate-based electrolytes by electrochemical impedance spectroscopy measurements and deposition/stripping galvanostatic cycling. Low amounts of tetraalkylammonium hexafluorophosphate salts have been added to the electrolytes with the aim of regulating the lithium deposition/stripping process through the electrostatic shielding effect that improves the lithium deposition. The use of NH4PF6 also determined good lithium deposition/stripping performance due to the chemical modification of the native solid electrolyte interphase via direct reaction with lithium.

Enabling Highly Reversible Zn Anode by Multifunctional Synergistic Effects of Hybrid Solute Additives

Aqueous zinc ion batteries are promising secondary batteries for next-generation electrochemical energy storage. In this work, we report a hybrid electrolyte system with 3 M Zn(OTf)2 as zinc salt and 1 M urea + 0.3 M LiOAc as hybrid solute additives for highly reversible aqueous zinc ion batteries. In this electrolyte system, partial coordinated water molecules of Zn2+ are replaced, and the original hydrogen bond network of the bulk electrolyte also suffers from interruption. Moreover, the introduction of lithium acetate solves the aggravated self-corrosion caused by urea on the one hand and inhibits the growth of dendrites through the electrostatic shielding effect on the other. Benefiting from this multifunctional synergistic effect, dendrite-free Zn plating/stripping for 600 h at 4.8 mA cm–2 (20% depth of discharge) and highly reversible plating/stripping at ∼99.7% Coulombic efficiency with a high cumulative plating capacity of 1600 mAh is achieved.

The structure, antioxidant activity, and stability of fish gelatin/chitooligosaccharide nanoparticles loaded with apple polyphenols.

Apple polyphenols (APs) with multiple biological effects have attracted extensive attention due to their broad opportunities for application. However, the use of APs is hampered by their instability in the face of environmental changes. Designing efficient carriers to improve the bioavailability of APs is the key to solving these problems. In this study, gelatin-chitooligosaccharide nanoparticles produced by the Maillard reaction (GCM) were fabricated to encapsulate AP, and the structure, antioxidant activity, and stability of the GMM-AP nanoparticle system were evaluated. The results of endogenous fluorescence spectrum, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, and simultaneous thermal analysis confirmed structural changes and interactions between GCM and AP. Combination with GCM did not adversely affect the antioxidant properties of AP, and the GCM-AP nanoparticles possessed superior temperature and storage stability. In comparison with fish gelatin-apple polyphenol nanoparticles, the GCM-AP nanoparticles were more stable at a wider pH range, and were more resistant to the electrostatic shielding effect of NaCl. After simulating gastric digestion, the particle size and polydispersity index (PDI) of GCM-AP nanoparticles were almost unchanged. The findings suggest that GCM nanoparticles loaded with AP could be used as good carriers with good antioxidant activity and stability. This study therefore provides a theoretical foundation for the development and industrial application of food functional factors. © 2023 Society of Chemical Industry.

Nitrogen-Doped and Sulfonated Carbon Dots as a Multifunctional Additive to Realize Highly Reversible Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (ZIBs) using the Zn metal anode have been considered as one of the next-generation commercial batteries with high security, robust capacity, and low price. However, parasitic reactions, notorious dendrites and limited lifespan still hamper their practical applications. Herein, an eco-friendly nitrogen-doped and sulfonated carbon dots (NSCDs) is designed as a multifunctional additive for the cheap aqueous ZnSO4 electrolyte, which can overcome the above difficulties effectively. The abundant polar groups (-COOH, -OH, -NH2 , and -SO3 H) on the CDs surfaces can regulate the solvation structure of Zn2+ through decreasing the coordinated active H2 O molecules, and thus redistribute Zn2+ deposition to avoid side reactions. Some of the negatively charged NSCDs are adsorbed on Zn anode surface to isolate the H2 O/SO4 2- corrosion through the electrostatic shielding effect. The synergistic effect of the doped nitrogen species and the surface sulfonic groups can induce a uniform electrolyte flux and a homogeneous Zn plating with a (002) texture. As a result, the excellent cycle life (4000h) and Coulombic efficiency (99.5%) of the optimized ZIBs are realized in typical ZnSO4 electrolytes with only 0.1mgmL-1 of NSCDs additive.

Imidazolium functionalized polysulfone/DTPA-chitosan composite beads for simultaneous removal of Cr(VI) and Cu(II) from aqueous solutions

Simultaneous removal of chromium(VI) oxyanions and heavy metal cations from contaminated water body is of great significance. In this work, a novel and bifunctional sorbent, imidazolium functionalized polysulfone/DTPA-chitosan composite bead (IMPSF/DACS) was successfully constructed by phase inversion method and applied for co-removal of Cr(VI) and Cu(II) from aqueous solutions. The maximum adsorption capacities for Cr(VI) and Cu(II) on IMPSF/DACS in single system at pH 5 were 56.72 and 43.05 mg g−1, respectively. In binary system, the removal of Cr(VI) could be further enhanced by the presence of Cu(II) due to the electrostatic shielding effect, while Cu(II) sorption was not significantly affected by the coexistence of Cr(VI). Moreover, IMPSF/DACS could simultaneously reduce low concentrations of Cu(II) and Cr(VI) in simulated contaminated lake water below the limit, while also showing good reusability in co-removal of Cr(VI) and Cu(II). The order of inhibitory effect of competing anions on Cr(VI) removal was as follows: H2PO4− < Cl− < NO3− < SO42−, while the competing hardness cations had a little effects on the adsorption of Cu(II), implying that the Cr(VI) removal was mainly depended on the electrostatic attraction between Cr(VI) and imidazolium ions modified on IMPSF/DACS, and Cu(II) uptake was associated with chelation of DACS encapsulated in IMPSF/DACS beads. These assumptions were confirmed by XPS, FTIR and EDS-mapping techniques.

Enabling uniform Li deposition behavior with dynamic electrostatic shield by the single effect of potassium cation additive for dendrite-free lithium metal batteries

The introduction of optimized amounts (0.010 M) of KTFSI additives results in preferential adsorption at the tip areas to form an electrostatic shielding effect, so that Li+ grows uniformly on other flat regions.

Electrostatic shielding effect and dynamic process of potential energy of metallic and nonmetallic elements

The ground-state energy is crucial for studying the properties of a material. In this study, we computed both the Hartree–Fock and random phase approximations of the ground state energy of metals and nonmetals. Considering the effect of the electrostatic shielding potential, we utilized the Thomas–Fermi dielectric function to obtain the Thomas–Fermi formula for the total potential energy. We calculated the total potential energy of the elements using the Wigner and Hedin–Lundqvist correlation energies, considering the changes in them after the electrostatic shielding effect. The exchange correlation potential, including electrostatic shielding effect, can be used in the measurement of scanning impedance microscopy experiments. Furthermore, we consider the dynamic process with respect to the change in the potential energy.

An advanced Ca/Zn hybrid battery enabled by the dendrite-free zinc anode and a reversible calcification/decalcification NASICON cathode

The proposal of hybrid ion batteries, which can integrate the advantages of the single ion battery, opens up a new route for developing high-performance secondary batteries. Herein, we successfully constructed an aqueous hybrid battery comprised of polyanionic-type cathode material (Na3V2(PO4)3, NVP), Zn metal anode, and aqueous Ca2+/Zn2+ hybrid electrolyte. This exciting combination gives full play to not only the excellent diffusion dynamics of Ca2+ in the NASICON (sodium super ion conductors) structure but also the electrostatic shielding effect of Ca2+ with low reduction potential that inhibits the formation of zinc dendrites. As results, the NVP//Zn Zn/Ca hybrid battery delivers favorable specific capacity with outstanding rate performance (85.3 mAh g−1 capacity at 1 C, 60.5 mAh g−1 capacity at 20 C), and excellent cycle stability (74 % capacity retention after 1300 cycles).

Influence of wire spacing and plate spacing on electrostatic precipitation of nanoparticles: An approach involving electrostatic shielding and diffusion charging

Electrostatic precipitation is a process widely used as gas cleaning device, to removal particles from gas flows. However, in a conventional and well-sized precipitator, the collection efficiency decreases for ultrafine particles, making it difficult to employ this equipment for controlling nanoparticle pollution. This paper investigates the influence of plate spacing (4 and 6.5 cm) and wire spacing (4, 6, and 12 cm) on the electric current and nanoparticle collection efficiency, considering the effect of diffusion charging and electrostatic shielding. Two laboratory-scale dry wire-plate electrostatic precipitators with different plate spacings were tested for the collection of nanoparticles (6.15–241.4 nm) at three air velocities (1.9, 2.9, and 3.9 cm/s). The results demonstrated the effectiveness of the equipment in removing nanoparticles (99.9%) under the highest electric fields. Higher values of the wire spacing led to increases in the current and the collection efficiency. This was associated with reduced electrostatic shielding, which is more evident in smaller ducts with a higher density of field lines. It is expected that the findings should improve knowledge on electrostatic precipitation of nanoparticles, enabling optimization of collection efficiency by considering the effects of geometric parameters.

Introducing KI as a functional electrolyte additive to stabilize Li metal anode

A lithium metal battery (LMBs) is an excellent battery system for advanced electrochemical energy storage. However, the growth of lithium dendrites, the accumulation of inactive lithium, and the side reactions between lithium metal and electrolytes limit the cycling stability of LMBs. Herein, we introduce KI additive into lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/ether-based electrolyte and lithium hexafluorophosphate (LiPF6)/ester-based electrolyte for cycling stability improvement of LMBs. Cu-mesh@Ag||Li half-cell with 0.01 M KI additive exhibits a Coulombic efficiency as high as 98.8 % over 200 cycles. The improved performance due to the electrostatic shielding effect formed by K+ at low concentration and the rapid recovery of inactive lithium by iodine redox. The corresponding Li||Li symmetrical cell shows an outstanding lifespan of 1400 h at 1.0 mA cm−2 with 1.0 mAh cm−2. Meanwhile, in the 1 M LiTFSI + 0.01 M KI electrolyte, the Cu-mesh@Ag-Li||LiFePO4 (LFP) full cell holds capacity retention of 91.7 % over 800cycles at 2.0 C, the Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) full cell possesses much better capacity retention of 54 % after 500 cycles at 1.0 C. This work offers a cost-effective proposal to improve application potential with the electrolyte engineering of rechargeable Li metal batteries.