Electrostatic Shielding Effect Research Articles

Electrostatic Shielding Engineering for Stable Zn Metal Anodes

AbstractAqueous Zn‐ion batteries (AZIBs) are promising energy storage systems due to their low cost, excellent safety, and environmental friendliness. However, challenges like uncontrollable dendrite growth and side reactions during battery operation limit their commercialization. Addressing these issues requires regulating ion deposition behavior at the anode/electrolyte interface. The electrostatic shielding effect, which leverages the interplay between electric potential and ionic motion, provides a unique mechanism to inhibit zinc dendrites and side reactions effectively. Despite significant progress in understanding electrostatic shielding in AZIBs, a comprehensive summary of its effects is still lacking. This paper first reviews the primary challenges in AZIBs and then describes how the electrostatic shielding effect can optimize their performance. Existing strategies for achieving electrostatic shielding through anode structure optimization and electrolyte optimization‐are classified and analyzed. Finally, the review summarizes current electrostatic shielding strategies for stabilizing zinc anodes, identifies existing challenges, and discusses the future potential, and for this approach in AZIBs.

Structure-property relationship of pea protein microgels as fat analogues in Pickering oil-in-water emulsions: effect of salt addition.

The design of plant-based microgels provides a platform for food ingredients to enhance palatability and functionality. This work aimed to explore the modifying effect of salt addition (KCl) on the structure of pea protein microgel particles (PPI MPs), on the interfacial adsorption and characteristics of formed emulsions as fat analogues. Salt addition (0-200 mmol L-1) promoted a structural transformation from α-helix to β-sheet, increased the surface hydrophobicity (from 1160.8 to 2280.7), and increased the contact angle (from 56.73° to 96.47°) of PPI MPs. The electrostatic shielding effect led to the tighter packing of MPs with irregular structures and lowered the adsorption energy barrier. Notably, salt-treated PPI MPs could adjust their adsorption state at the interface. The discernible adsorption of PPI MPs with 200 mmol L-1 salt addition that possessed enhanced anti-deformation ability dominated the interfacial stabilization, whereas a relatively rougher stretched continuous interfacial film formed after spreading and deformation of 0 mmol L-1 MPs. A tribological test suggested that emulsion stabilized by MPs at 0 (0.0053) and 80 mmol L-1 (0.0068) had similar friction coefficients to commercial mayonnaise (0.0058), whereas a higher salt concentration (200 mmol L-1) lowered its oral sensation due to the adsorption layer and enhanced the resistance to droplet coalescence during oral processing. Salt could be a modifier to tune the structure of microgels, and further promote the formation and attributes of emulsions. This study would improve application attributes of PPI MPs in the design of realistic fat analogues. © 2024 Society of Chemical Industry.

Solid polymer electrolytes with dual salts enhance lithium-metal interfacial stability for long cycle performance of lithium batteries

Solid-state lithium metal batteries (LMBs) are considered to be the ideal energy storage system for achieving higher energy density and high safety. However, poor physical contact at the interface between the solid-state electrolyte and lithium metal, as well as the growth of dendrites make the cycling stability of LMBs challenging. Therefore, we developed a multifunctional ionic liquid-based polymer electrolyte including montmorillonite (MMT) and double salts (NaFSI and LiTFSI). The self-concentration effect of MMT lithium ions, combined with the electrostatic shielding effect of the double salts, resulted in homogeneous ion deposition, reducing dendritic lithium generation and improving lithium battery performance, with lithium batteries achieving a stable cycling rate of 1000 cycles at 1 C. Moreover, Due to the integrated assembly of the battery assembly process using light curing, the physical interface between the positive electrode-electrolyte-negative electrode achieves good contact and wettability. NaFSI achieves the enhancement of solid electrolyte interface (SEI) by introducing NaF/LiF to SEI of lithium metal, and the optimization of ion deposition pattern at the interface can be achieved by electrostatic shielding effect. Ultimately, stable ion transport at the solid-solid interface for lithium metal solid-state batteries can be realized. Notably, the ionic liquid-based polymer electrolyte with high ionic conductivity (1.2 × 10−3 S cm−1) and high oxidative stability (5.2 V vs. Li/Li+) at room temperature. In addition, the good flame retardant properties of the electrolytes indicate that dual-salt polymer electrolytes are an effective strategy for achieving high safety and long cycle stability of LMBs.

Enhancing Zinc Anode Stability with Gallium Ion‐Induced Electrostatic Shielding and Oriented Plating

AbstractThe cost‐effectiveness and environmental benefits of aqueous zinc‐ion batteries (ZIBs) have attracted considerable attention. However, practical applications are hindered by side processes including dendritic growth and hydrogen evolution corrosion. Herein, gallium ions (Ga3+) have been chosen as a multifunctional electrolyte additive to improve the reversibility of zinc‐ion batteries (ZIBs). Remarkably, Ga3+ ions adhere to the anode surface, establishing a dynamic electrostatic shielding layer that modulates Zn2+ deposition and prevents side reactions. Typically, Ga3+ ions preferentially adsorb onto the (002) and (110) planes of Zn, facilitating preferential deposition on the (100) plane, resulting in a dendrites‐free zinc anode. Consequently, the Zn||Zn symmetrical cell with Ga3+‐modified electrolyte demonstrates a prolonged lifespan of 4000 h, while the Zn||Ti asymmetric cell exhibits an impressive coulombic efficiency of 99.12% for zinc stripping and plating at 2 mA cm−2. Additionally, the Zn||VO2 cell maintains high capacity retention after 1500 cycles at 5 A g−1. This work presents Ga3+ ions as an electrolyte additive, facilitating the development of a durable dynamic electrostatic shielding effect and preferential (100) plane electroplating, ensuring zinc deposition free from dendrite formation. Such discoveries form a basis for future investigations into novel materials to propel advancements in metal battery technology.

Cation Adsorption Engineering Enables Dual Stabilizations for Fast‐Charging Zn─I2 Batteries

AbstractAqueous zinc‐iodine (Zn─I2) battery is a promising energy storage system due to its inherent safety, high theoretical capacity, sustainability, and cost‐effectiveness. However, the shuttle effect of polyiodide severely affects the stable loading of active iodine and even accelerates the corrosion of the Zn anode, thus impeding its further advancement. Herein, a unique trimethylsulfonium cation (TMS+) with strong adsorption is proposed to stabilize both the iodine cathode and Zn anode. Benefiting from the robust interaction between TMS+ and polyiodide, the electrolyte can effectively immobilize large‐capacity iodine in the form of oily precipitate, thus avoiding the shuttle effect of polyiodide and the Zn corrosion. Additionally, TMS+ can be preferentially adsorbed on various Zn facets, inducing an electrostatic shielding effect to inhibit Zn dendrite growth. Consequently, Zn anode can be stably cycled over 3400 h at 5 mA cm−2/5 mAh cm−2, and a large areal capacity of 2.71 mAh cm−2 as well as long‐life stability over 6400 cycles is achieved for Zn─I2 battery. Furthermore, cation adsorption engineering is practically utilized in pouch cells, realizing superior fast‐charging stability over 790 cycles. This electrolyte modification with dual stabilizations is anticipated to be applied to other metal‐iodine batteries as a cost‐effective, facile, and safe strategy.

Dual-Functional Interfacial Layer Enabled by Gating-Shielding Effects for Ultra-Stable Zn Anode.

Large-scale application of low-cost, high-safety and environment-compatible aqueous Zn metal batteries (ZMBs) is hindered by Zn dendrite failure and side reactions. Herein, highly reversible ZMBs are obtained by addition of trace D-pantothenate calcium additives to engineer a dual-functional interfacial layer, which is enabled by a bioinspired gating effect for excluding competitive free water near Zn surface due to the trapping and immobilization of water by hydroxyl groups, and guiding target Zn2+ transport across interface through carboxyl groups of pantothenate anions, as well as a dynamic electrostatic shielding effect around Zn protuberances from Ca2+ cations to ensure uniform Zn2+ deposition. In consequence, interfacial side reactions are perfectly inhibited owing to reduced water molecules reaching Zn surface, and the uniform and compact deposition of Zn2+ is achieved due to promoted Zn2+ transport and deposition kinetics. The ultra-stable symmetric cells with beyond 9000h at 0.5mAcm-2 with 0.5mAhcm-2 and over 5000h at 5mAcm-2 with 1mAhcm-2, and an average Coulombic efficiency of 99.8% at 1mAcm-2 with 1mAhcm-2, are amazingly realized. The regulated-electrolyte demonstrates high compatibility with verified cathodes for stable full cells. This work opens a brand-new pathway to regulate Zn/electrolyte interface to promise reversible ZMBs.

Effect of alkali-metal phosphate additives on the interphase structure of 5-V LiNi0.5Mn1.5O4-based lithium–ion batteries

High-voltage (5-V) lithium–ion batteries (LIBs) have garnered substantial interest due to their superior energy density. Nevertheless, the unstable interphase of high-voltage LIBs can cause electrolyte decomposition, electrode collapse, transition metal dissolution, and lithium dendrite growth during cycling, which impedes their widespread commercial use. To mitigate these challenges, various alkali-metal phosphates were incorporated into a carbonate-based electrolyte as film-forming additives, aiming to improve the electrochemical performance of LiNi0.5Mn1.5O4 (LNMO)-based LIBs. Following a detailed comparison of the electrochemical performances of various alkali-metal phosphates, KH2PO4 and NaH2PO4 were selected for an in-depth investigation in this research. The highly protective passivation film generated by KH2PO4 and NaH2PO4 on the electrode surface provided significant protection by effectively inhibiting continuous electrolyte decomposition. This finding was supported by density functional theory calculations and a variety of electrochemical and characterization tests. The H2PO4− primarily contributed to the formation of the cathode electrolyte interphase film on the cathode surface. KH2PO4 (via the electrostatic shielding effect of K+ions) and NaH2PO4 (through the co-precipitation of Na+ and Li+ ions) both effectively inhibited the growth of lithium dendrites on the lithium metal anode. Additionally, the KH2PO4 and NaH2PO4 additives regulated the amount of HF in the electrolyte through acid–base equilibrium reactions. The electrolytes containing additives significantly enhanced the electrochemical performances of Li||Li, LNMO/Li, LNMO/graphite, and LNMO/Li4Ti5O12 cells. LNMO/Li half-cells with standard electrolyte (STD) supplemented with KH2PO4 and NaH2PO4 additives demonstrated capacity retentions of 92.9 % and 90.0 % after 500 cycles at 5 C, respectively, in contrast to only 79.4 % for the STD electrolyte alone. Furthermore, the LNMO/graphite full cell exhibited an increased capacity retention, reaching 81.1 % (STD+KH2PO4) and 78.29 % (STD+NaH2PO4), up from 70.8 % with the STD, after 100 cycles at 0.5 C. Given their ease of use, affordability, and widespread availability, KH2PO4 and NaH2PO4 additives show significant potential to enhance the electrochemical properties of high-voltage LIBs.

A Versatile Redox-Active Electrolyte for Solid Fixation of Polyiodide and Dendrite-Free Operation in Sustainable Aqueous Zinc-Iodine Batteries.

Practical utilization of zinc-iodine (Zn-I2) batteries is hindered by significant challenges, primarily stemming from the polyiodide shuttle effect on the cathode and dendrite growth on the anode. Herein, a feasible redox-active electrolyte has been introduced with tetraethylammonium iodide as an additive that simultaneously addresses the above mentioned challenges via polyiodide solidification on the cathode and the electrostatic shielding effect on the anode. The tetraethylammonium (TEA+) captures water-soluble polyiodide intermediates (I3 -, I5 -), forming a solid complex at the cathode, thereby suppressing capacity loss during charge/discharge. Furthermore, the TEA+ mitigates dendrite growth on the Zn anode via the electrostatic shielding effect, promoting uniform and compact Zn deposition at the anode. Consequently, the Zn||Zn symmetric cell demonstrates superior cycling stability during Zn plating/stripping over 4,200h at 1mA cm-2 and 1 mAh cm-2. The Zn||NiNC full-cell exhibits a stable capacity retention of 98.4% after 20000 cycles (>5 months) with near-unity Coulombic efficiency at 1 A g-1. The study provides novel insights for establishing a new direction for low-cost, sustainable, and long-lifespan Zn-I2 batteries.

Dual ion regulation enables High-Coulombic-efficiency lithium metal batteries

Lithium (Li) metal batteries are ideal alternatives for pursuing high-energy-density batteries. Nevertheless, their subpar cycling capabilities and safety problems remain a significant concern because of the insufficient reversibility of Li plating/stripping processes. Herein, potassium trifluoromethanesulfonate (KOTf) is proposed as an electrolyte additive to achieve high Coulombic efficiency during cycling, which could be assigned to the synergistic regulation effect of anions and cations in KOTf. On the one hand, the OTf- helps form an anion-rich solvation structure, which could be preferentially reduced to obtain a robust and conductive inorganic-rich SEI film to stabilize the lithium metal anode. On the other hand, the existence of K+ induces the generation of K+-rich positive charge shielding layer, further hindering the growth of Li dendrite. The KOTf-assisted Li||Cu cell shows a high Coulombic efficiency (CE) of 99.7 % and an extremely long-cycle life of 700 cycles with an average CE of 99.01 % under 0.5 mA cm−2 and 0.5 mAh cm−2. The excellent lithium metal stripping/plating efficiency is mainly due to the OTf--derived inorganic-rich SEI and the electrostatic shielding effect of K+. This work emphasizes the important role of salts’ anions and cations in determining the CE of LMBs and provides an effective strategy to improve the cycling performance of LMBs.

Interfacial Domino Effect Triggered by β-Alanine Cations Realized Highly Reversible Zinc-Metal Anodes.

Realizing durative dense, dendrite-free, and no by-product deposition configuration on Zn anodes is crucial to solving the short circuit and premature failure of batteries, which is simultaneously determined by the Zn interface chemistry, electro-reduction kinetics, mass transfer process, and their interaction. Herein, this work unmasks a domino effect of the β-alanine cations (Ala+) within the hydrogel matrix, which effectively triggers the subsequent electrostatic shielding and beneficial knock-on effects via the specifical adsorption earliest event on the Zn anode surface. The electrostatic shielding effect regulates the crystallographic energetic preference of Zn deposits and retards fast electro-reduction kinetics, thereby steering stacked stockier block morphology and realizing crystallographic optimization. Meanwhile, the mass transfer rate of Zn2+ ions was accelerated via the SO4 2- anion immobilized caused by Ala+ in bulk electrolyte, finally bringing the balance between electroreduction kinetics and mass transfer process, which enables dendrite-free Zn deposition behavior. Concomitantly, the interfacial adsorbed Ala+ cations facilitate the electrochemical reduction of interfacial SO4 2- anions to form the inorganic-organic hybrid solid electrolyte interphase layer. The above domino effects immensely improve the utilization efficiency of Zn anodes and long-term stability, as demonstrated by the 12 times longer life of Zn||Zn cells (3650 h) and ultrahigh Coulombic efficiency (99.4 %).

Interfacial Domino Effect Triggered by β‐Alanine Cations Realized Highly Reversible Zinc‐Metal Anodes

AbstractRealizing durative dense, dendrite‐free, and no by‐product deposition configuration on Zn anodes is crucial to solving the short circuit and premature failure of batteries, which is simultaneously determined by the Zn interface chemistry, electro‐reduction kinetics, mass transfer process, and their interaction. Herein, this work unmasks a domino effect of the β‐alanine cations (Ala+) within the hydrogel matrix, which effectively triggers the subsequent electrostatic shielding and beneficial knock‐on effects via the specifical adsorption earliest event on the Zn anode surface. The electrostatic shielding effect regulates the crystallographic energetic preference of Zn deposits and retards fast electro‐reduction kinetics, thereby steering stacked stockier block morphology and realizing crystallographic optimization. Meanwhile, the mass transfer rate of Zn2+ ions was accelerated via the SO42− anion immobilized caused by Ala+ in bulk electrolyte, finally bringing the balance between electroreduction kinetics and mass transfer process, which enables dendrite‐free Zn deposition behavior. Concomitantly, the interfacial adsorbed Ala+ cations facilitate the electrochemical reduction of interfacial SO42− anions to form the inorganic‐organic hybrid solid electrolyte interphase layer. The above domino effects immensely improve the utilization efficiency of Zn anodes and long‐term stability, as demonstrated by the 12 times longer life of Zn||Zn cells (3650 h) and ultrahigh Coulombic efficiency (99.4 %).

Study on the rheological properties and salt resistance mechanism of an amphiphilic polymer with twin-tailed group

Partially hydrolyzed polyacrylamide (HPAM) is the most widely used polymer for oil recovery. Its thickening ability has been severely compromised in high salinity reservoirs. To improve polymer viscosity in high salinity reservoirs, a twin-tailed amphiphilic polymer P(AM/AMPS/DtC18) was developed by radical copolymerization method using AM, AMPS and DtC18 monomers, abbreviated as PAAD18. The contrast polymer P(AM-AMPS) was prepared by the same method and reaction conditions. The structure of PAAD18 was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and H Nuclear Magnetic Resonance Spectra (1H NMR). The relationship between its rheological properties and microstructure was studied using rheological analysis and Scanning Electron Microscope (SEM). The mechanism of salt resistance was revealed. The results show that under the condition of XJ reservoir with 98558 mg/L and 40℃, the viscosity of PAAD18 with concentration of 2200 mg/L is 25 mPa·s. PAAD18 has better temperature and salt resistance than HPAM and P(AM-AMPS). P(AM-AMPS) has better temperature resistance and salt resistance than HPAM. The salinity ranges from 0 to 5 × 104 mg/L, the viscosity of PAAD18 is reduced due to the action of electrostatic shielding. At a salinity of 5 × 104 mg/L, the electrostatic shielding effect and the hydrophobic association effect reach a balanced point, and the solution viscosity is the lowest. The salinity increases from 5 × 104 mg/L to 15 × 104 mg/L, then the hydrophobic association is enhanced due to the increased polarity of the solution. It was found that the polymer network structure of PAAD18 was more complex, the viscosity of the solution increased instead. The salt thickening properties were demonstrated in the rheology measurement. This work provides a new material for polymer flooding technology in high salinity reservoirs, with good application potential and guiding significance.

Regulating the inner Helmholtz plane with an electrophilic cation additive enabled stacked stratiform growth for highly reversible Zn anodes

Achieving consecutive flattening and dendrite-free deposition for the zinc anodes is essential to avoid internal short circuits or premature failure in the Zn-ion hybrid supercapacitor (ZHSC), which largely depends on the crystal growth during the electrocrystallization process. Herein, the tetrapropyl ammonium bromide additive was employed to reconstruct the inner Helmholtz plane (IHP) structure for manipulating the Zn deposition behavior and stabilizing the interfacial electrochemistry. Joint experimental and theoretical results show that electrophilic quaternary ammonium cations (TPA+) provoke the linkage effect after the specifical adsorption at IHP of the Zn electrode, which includes the molecular/ion distribution regulation, electrostatic shielding effect, crystallographic optimization, and solid electrolyte interphase (SEI) layer formation. The adsorbed TPA+ cations at IHP expel SO42− anions, bringing a reconfiguration of the ion/molecule distribution, which leads to a relatively uniform Zn2+ions distribution at electrode/electrolyte interface and a sluggish electroreduction reaction kinetics. Meanwhile, the electrostatic shielding effect regulates the crystallographic energetic preference of Zn deposits and induces the stratiform Zn growth and dominant Zn (002) texture. Concomitantly, the partial interfacial adsorbed TPA+ cations were electrochemically reduced to form the inorganic-organic hybrid SEI layer to further enhance the corrosion resistance and stability of the Zn electrode. Consequently, TPA+ cations mediated electrolyte enables Zn||Zn cells to exhibit a reversible plating/stripping performance for more than 2800 h. Additionally, a long-term cycling life can be obtained in the Zn||activated carbon ZHSC with this electrolyte. The electrolyte mediation strategy to realize the complementary interface effect and crystalline optimization provides promising feasibility on highly reversible Zn anodes.

Experimental and theoretical analysis of loading characteristics of electret filter media for charged particles

The degradation of filtration performance in electret filter media during usage poses a significant challenge. Pre-charging of aerosols has been identified as an effective method to mitigate this issue. However, the effects of particle charging characteristics on the loading characteristics of electret filters still need a comprehensive understanding. In this study, a needle-cylinder corona charger was employed to pre-charge aerosols, and the particle charge state was determined by multiphysics simulation. The effects of particle charge polarity and charge quantity on the loading performance of the electret filter were quantitatively investigated. The results showed that the particle charge polarity had a negligible impact on the loading performance under the condition of the equivalent particle charge quantity. In addition, the charged particles effectively improved the efficiency degradation during the loading process of electret media, with higher charge quantities resulting in more pronounced improvements. The electrostatic attenuation factor showed a negative exponential correlation with the particle charge quantity. This was attributed to the uneven particle deposition on fiber surface due to the attraction of charged particles by the opposite charges on the electret fibers, which alleviated the effect of electrostatic shielding.

Partially solvated cosolvent induced reconfiguration of solvation structure and Helmholtz layer for lithium metal battery

Reconfiguring the electrolyte microstructure containing Li+ solvation structure in bulk electrolyte and Helmholtz layer (HL) near the interface presents a compelling strategy in the design of electrolytes. In this work, ionic liquids (ILs) and partially solvated fluorobenzene (FB) build the unique Li+ coordination state modulated by FB and dominated by anions as well as a HL enriched in non-sacrificial cations on charging. As an important part to regulate the micro environment, FB not only enhances the ion transport kinetics of electrolyte and promotes the interaction of Li+-FSI−, but also participates in constructing a robust solid electrolyte interphase (SEI). Interestingly, FB indirectly promotes the enrichment of ILs’ cations at the HL, which is beneficial for uniform Li metal deposition due to its electrostatic shielding effect. Lithium metal batteries utilizing this electrolyte demonstrate impressive cycling performance at a high rate (approximately 89% capacity retention after 2,500 cycles at 5 C). Furthermore, these cells show excellent high-temperature performance, maintaining 71% of the initial capacity after 1,000 cycles at 70°C and 10 C rate.

A Water‐Insoluble Yttrium‐Based Complex as Dual‐Ionic Electrolyte Additive for Stable Aqueous Zinc Metal Batteries

AbstractAqueous batteries employing Zinc metal anodes (ZMAs) are considered to be promising next‐generation energy storage systems. However, the severe interfacial side reactions and dendrite growth restrict the practical application of ZMAs in aqueous electrolytes. Herein, a water‐insoluble dual‐ionic electrolyte additive of yttrium 2,4,5‐trifluorophenylacetate (YTFPAA) is developed to stabilize the aqueous ZMAs. Notably, the ethanol‐solvated TFPAA− can capture H+ and thus buffer the decreased electrolyte pH caused by the hydrolysis of Y3+. Furthermore, the ethanol‐solvated TFPAA− can dynamically adsorb onto the surface of ZMAs through a reversible oxidation‐reduction reaction, effectively suppressing the interfacial side reactions by forming a water‐poor interface, and enhancing the reversibility of Zn2+ deposition/stripping by redistributing the Zn2+ flux. These favorable effects of TFPAA− combined with the dynamic electrostatic shielding effect of Y3+ ultimately enable uniform and dense Zn2+ deposition. As a result, the Zn/Zn cells assembled with 0.25YTFPAA electrolyte exhibit an impressive cycle life of 2100 h at 0.5 mA cm−2–0.25 mAh cm−2. More importantly, the assembled V2O5/Zn full cell shows an ultra‐long cycle life of up to 18000 cycles at 5.0 A g−1. This work highlights the rational design of multifunctional ionic additives for stabilizing aqueous ZMAs.

Effects of hydrogen bonding and electrostatic interactions on the formation of rice starch-Mesona chinensis polysaccharide gels

Non-covalent forces are essential for the formation of starch-Mesona chinensis polysaccharide (MCP) gels. In this paper, the effects of hydrogen bonding and electrostatic interactions on the formation of rice starch (RS)-MCP gels. The addition of urea broke the hydrogen bonds and loosened the microstructure, reducing the gel viscosity, pasting temperature, and water molecule binding capacity. The decreased short-range ordering and double-helix structure corroborated the reduction of gel properties. Gaussian fitting showed that the intermolecular hydrogen bonding between RS and MCP was dominated by OH⋯π. Low concentrations of NaCl decreased the electrostatic repulsion between RS and MCP and promoted the formation of gel structure. The electrostatic shielding effect occurred with increasing NaCl concentration, and the storage modulus (G′) and melting enthalpy decreased. Compared to the changes in the electrostatic effect, the breaking of hydrogen bonds disrupted the gel structures obviously, therefore, hydrogen bonds were the main interaction force in gel formation. The research explored the effect on gel properties based on the changes in non-covalent force, which provided a new insight into starch-polysaccharide interactions. Concurrently, it also presented a novel entry point for research efforts to modulate the properties of gels.

Multifunctional polyzwitterion ionic liquid based solid-state electrolytes for enhancing the low-temperature performance of lithium-metal batteries

The extensive development of solid-state batteries (SSB) is still hindered by their insufficient charge transfer kinetics and severe interfacial problems at low temperatures. In this paper, a polyzwitterion ionic liquid based solid-state electrolyte (SSE) containing fluoroalkyl side chains is developed. The Lewis acid segment in the polymer backbone enhances the dissociation of lithium salts and modulates the Li+ transport. The experimental results showed that the −SO3- groups at the end of the zwitterions constructed a fast ion transport pathway, and the fluoroalkyl side chain can weaken the affinity between Li+ and the coupling site. In addition, the electrostatic shielding effect of zwitterions at the interface mitigated the tip effect, and the fluorinated alkyl side chains participated in the SEI film formation. As a result, the ionic conductivity of the designed electrolyte is as high as 1.39 × 10-4 S cm−1 at −30 °C, and the polarization rate of Li||Li symmetric battery at −10 °C is about 80 mV after 4000 h. The assembled Li||LiFePO4 pouch full cell delivers impressive performance in the wide temperature range from –23 to 99 °C. The proposed strategy has considerable potential for SSB application at low temperatures.

Proton-driven bilateral interfacial chemistry and electrolyte structure reconstruction enable highly reversible zinc metal anodes

Uncontrolled dendrite growth, severe parasitic reactions on the Zn metal anode (ZMA), and the dissolution of cathode active materials have significantly limited the development of aqueous zinc ion batteries. Herein, 3-(Cyclohexylamino)-1-propanesulfonic acid (CAPS) featured with zwitterion as a multifunctional additive is introduced into the 2 M ZnSO4 aqueous electrolyte to simultaneously regulate the interfacial chemistry of the Zn anode and the cathode, as well as the solvated structure of Zn2+, thereby improving the interfacial and structural stability of both electrodes. Thereinto, the preferentially adsorbed CAPS zwitterion onto the ZMA surface favors for constructing a cationic protective layer originated from the electrostatic shielding effect of the cationic group (>NH2+), inhibiting the growth of dendrites. Meanwhile, the CAPS zwitterion can self-regulate the bilateral interfacial pH by forming the conjugate acid-base pair, suppressing hydrogen evolution reaction and Zn anode surface corrosion. Additionally, the CAPS zwitterion alters the solvated structure of Zn2+, weakening H2O molecule activity and reducing the dissolution of vanadium element from cathode. Consequently, the Zn||Zn symmetric cells harvest excellent cycling stability (1 mA cm−2, 1 mAh cm−2, 2300 h), and the Zn||Cu asymmetric cells display a high average Coulombic Efficiency of 99.7 % after 1600 cycles in the ZnSO4+CAPS electrolyte.

Propagation effect of lightning electromagnetic field along real ground surface and its validation on correcting lightning location system errors

Artificially triggered lightning experimental data from Guangdong Comprehensive Observation Experimental Base on Lightning Discharge (GCOELD) was applied to analyze the propagation effect of lightning electromagnetic field along the real ground surface. The accuracy of the finite-difference time-domain (FDTD) on correcting lightning location system (LLS) errors was validated compared with the Elevation Model (EM). Results show that the wave-shape and time-delay of electromagnetic fields can be significantly affected when they propagate over the real ground surface. The time-delay of the field waveform become larger with an increasing roughness. The wavefront electric field is enhanced due to the reflection and variant of the wave when lightning waves propagate across the high and sharp terrain. Near the lightning strokes, the peak of vertical electric value decreases significantly with the electrostatic shielding effect. The max time delay calculated by FDTD is 8.34 μs; while that by EM is 6.55 μs. In the selected nine lightning stroke points, eight are positively revised by EM, and five by FDTD. Both FDTD and EM can be used on LLS error revision caused by the real ground surface around GCOELD, although EM is more efficient than FDTD in this case.