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Short nanopores find extensive applications, capitalizing on their high throughput and detection resolution. Ionic behaviors through long nanopores are mainly determined by charged inner-pore walls. When pore lengths decrease to sub-200 nm, charged exterior surfaces provide considerable modulation to ion current. We find that the charge status of inner-pore walls affects the modulation of ion current from charged exterior surfaces. For 50-nm-long nanopores with neutral inner-pore walls, the charged exterior surfaces on the voltage (surfaceV) and ground (surfaceG) sides enhance and inhibit the ion transport by forming ion enrichment and depletion zones inside nanopores, respectively. For nanopores with both charged inner-pore and exterior surfaces, continuous electric double layers enhance the ion transport through nanopores significantly. The charged surfaceV results in higher ion current by simultaneously weakening the ion depletion at pore entrances and enhancing the intra-pore ion enrichment. The charged surfaceG expedites the exit of ions from nanopores, resulting in a decrease in ion enrichment at pore exits. Through adjustment in the width of charged-ring regions near pore boundaries, the effective charged width of the charged exterior is explored at ∼20 nm. Our results may provide a theoretical guide for further optimizing the performance of nanopore-based applications, such as seawater desalination, biosensing, and osmotic energy conversion. [ABSTRACT FROM AUTHOR]

Increasingly, society requires high power, high energy storage devices for applications ranging from electric vehicles to buffers on the electric grid. Supercapacitors are a promising contribution to meeting these demands, though there still remain unsolved practical problems. Molecular dynamics simulations can shed light on the relevant molecular level processes in electric double layer capacitors, but these simulations are computationally very demanding. Our focus here is on the algorithmic complexity of the constant potential method (CPM), which uses dedicated electrostatics solvers to maintain a fixed potential difference between two conducting electrodes. We show how any standard electrostatics solver—capable of calculating the energies and forces on all atoms—can be used to implement CPM with a minimum of coding. As an example, we compare our generalized implementation of CPM, based on invocations of the particle–particle–particle–mesh routine of the Large-scale Atomic/Molecular Massively Parallel Simulator, with a traditional implementation based on a dedicated re-implementation of Ewald summation. Both methods yield comparable results on four test systems, with the former achieving a substantial gain in speed and improved scalability. The step from dedicated electrostatic solvers to generic routines is made possible by noting that CPM's traditional narrow Gaussian point-spread of atomic charges on the electrodes effectively endows point-like atoms with chemical hardness, i.e., an intra-atomic energy quadratic in the charge. [ABSTRACT FROM AUTHOR]

The electric double layer (EDL) has a pivotal role in screening charges on surfaces as in supercapacitor electrodes or colloidal and polymer solutions. Its structure is determined by correlations between the finite-sized ionic charge carriers of the underlying electrolyte, and, this way, these correlations affect the properties of the EDL and of applications utilizing EDLs. We study the structure of EDLs within classical density functional theory (DFT) in order to uncover whether a structural transition in the first layer of the EDL that is driven by changes in the surface potential depends on specific particle interactions or has a general footing. This transition has been found in full-atom simulations. Thus far, investigating the in-plane structure of the EDL for the primitive model (PM) using DFT has proved a challenge. We show here that the use of an appropriate functional predicts the in-plane structure of EDLs in excellent agreement with molecular dynamics simulations. This provides the playground to investigate how the structure factor within a layer parallel to a charged surface changes as a function of both the applied surface potential and its separation from the surface. We discuss pitfalls in properly defining an in-plane structure factor and fully map out the structure of the EDL within the PM for a wide range of electrostatic electrode potentials. However, we do not find any signature of a structural crossover and conclude that the previously reported effect is not fundamental but rather occurs due to the specific force field of ions used in the simulations. [ABSTRACT FROM AUTHOR]

In this paper, we present a continuation of our research on modeling electrolyte solutions within charged pores. We make use of the model developed by Blossey et al. [Phys. Rev. E 95, 060602 (2017)], which takes into account the structural interactions between ions through a bilinear form over the gradients of local ionic concentrations in the grand thermodynamic potential, as well as their steric interactions through the lattice gas model. The structural interactions may describe the effects of the molecular structure of ions at a phenomenological level. For example, these effects include steric effects due to non-spherical shapes of ions, their conformational lability, and solvent effects. In addition, we explore their specific interactions with the pore walls by incorporating external attractive potentials. Our primary focus is on observing the behavior of ionic concentration profiles and the disjoining pressure as the pore width changes. By starting with the local mechanical equilibrium condition, we derive a general expression for the disjoining pressure. Our findings indicate that considering the structural interactions of ions leads to a pronounced minimum on the disjoining pressure profiles at small pore widths. We attribute this minimum to the formation of electric double layers on the electrified surfaces of the pore. In addition, our results demonstrate that the inclusion of the attractive interactions of ions with the pore walls enhances this minimum and shifts it to smaller pore thicknesses. Our theoretical discoveries may be useful for those involved in supercapacitor electrochemical engineering, particularly when working with porous electrodes that have been infused with concentrated electrolyte solutions. [ABSTRACT FROM AUTHOR]

Understanding the electric double layer (EDL) of the metal electrode–electrolyte interface is essential to electrochemistry and relevant disciplines. In this study, potential-dependent electrode Sum Frequency Generation (SFG) intensities of polycrystalline gold electrodes in HClO4 and H2SO4 electrolytes were thoroughly analyzed. The potential of zero charges (PZC) of the electrodes was −0.06 and 0.38 V in HClO4 and H2SO4, respectively, determined from differential capacity curves. Without specific adsorption, the total SFG intensity was dominated by the contribution from the Au surface and increased similar to that of the visible (VIS) wavelength scanning, which pushed the SFG process closer to the double resonant condition in HClO4. However, the EDL contributed about 30% SFG signal with specific adsorption in H2SO4. Below PZC, the total SFG intensity was dominated by the Au surface contribution and increased with potential at a similar slope in these two electrolytes. Around PZC, as the EDL structure became less ordered and the electric field changed direction, there would be no EDL SFG contribution. Above PZC, the total SFG intensity increased much more rapidly with potential in H2SO4 than in HClO4, which suggested that the EDL SFG contribution kept increasing with more specific adsorbed surface ions from H2SO4. [ABSTRACT FROM AUTHOR]

In this work, the planar, electric, double-layer structures of non-polarizable electrodes in electrolyte solutions are studied with Gaussian field theory. A response function with two Yukawa functions is used to capture the electrostatic response of the electrolyte solution, from which the modified response function in the planar symmetry is derived analytically. The modified response function is further used to evaluate the induced charge density and the electrostatic potential near an electrode. The Gaussian field theory, combined with a two-Yukawa response function, can reproduce the oscillatory decay behavior of the electric potentials in concentrated electrolyte solutions. When the exact sum rules for the bulk electrolyte solutions and the electric double layers are used as constraints to determine the parameters of the response function, the Gaussian field theory could at least partly capture the nonlinear response effect of the surface charge density. Comparison with results for a planar electrode with fixed surface charge densities from molecular simulations demonstrates the validity of Gaussian field theory. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries have been regarded as safe and cheap energy storage devices. However, severe zinc dendrite growth and water decomposition limit the sustainability of aqueous zinc‐ion batteries. Herein, sodium‐difluoro(oxalato)borate (NaDFOB) is introduced into ZnSO4 electrolyte to modify the electric double layer (EDL) and the nucleation mechanism. Electrochemical tests and density functional theory calculations reveal that DFOB− adsorbs on the zinc electrode to form a water‐poor EDL, effectively suppressing side reactions. Notably, a detailed investigation of zinc deposition demonstrates that the adsorbed DFOB− ions induce progressive nucleation, resulting in nanoscale zinc nuclei and uniform zinc growth. Additionally, the adsorbed DFOB− ions decompose into a solid electrolyte interphase, further protecting the zinc electrode. Consequently, the Zn/Zn symmetric cell using ZnSO4/NaDFOB electrolyte can cycle for over 500 h at 5 mA cm−2 to reach a capacity of 10 mAh cm−2, while a Zn/Cu half cell maintains an average Coulombic efficiency of 99.3% over 400 cycles. A high capacity retention of 93.0% with a capacity of 250 mAh g−1 at 0.2 A g−1 is achieved in the ZnSO4/NaDFOB electrolyte in full cell cycling. These findings highlight the impact of anion‐modified EDL and progressive nucleation on achieving highly uniform zinc deposition. [ABSTRACT FROM AUTHOR]

The structures and properties of the electric double layer (EDL) on zinc (Zn) anodes significantly influence the cycling and rate performance of aqueous Zn batteries (ZBs). Here, a strategy is reported to regulate the EDL structure through work function (Wf) engineering to effectively enhance the electrochemical performance of ZBs, which is enabled by electrolyte‐tailored growth of heterogenous metal with a large Wf on the Zn anode. The metal‐to‐metal charge transfer in heterostructured Zn metal induced by the disparity of Wf increases the surface charge density, which enriches the Zn ions and shortens the thickness of EDL. The compressed EDL weakens the repulsive force of Zn deposits to achieve a tightly stacked and dendrite‐free Zn deposition. Besides, the formed H2O‐deficient EDL structure enables the inorganic‐rich solid electrolyte interphase (SEI) with high Zn‐ion conductivity to inhibit the notorious parasitic reactions and improve the electrode reaction kinetics. Consequently, the Zn||Zn symmetric cells demonstrate an ultra‐long cycling life over 2700 cycles (the cumulative capacity reaches 5400 mA h cm−2) at a high current density of 50 mA cm−2. The Zn anodes show a high average Coulombic efficiency of 99.70% over 3650 cycles. The Zn||MnO2 full cells exhibit excellent practical‐level performance under cyclic continuous mode (3000‐cycle life at high rates) and cyclic intermittent mode (1170‐cycle life with 83.05% capacity retention). Practical pouch cells are also demonstrated with outstanding cycling performance. [ABSTRACT FROM AUTHOR]

Although the flexibility of the quasi−solid polymer electrolyte favors its surface conformal to the electrode, interfacial damage originating from side reactions between the electrolyte and the electrode remains dominant for battery failure. The design of quasi−solid electrolytes compatible with both aggressive nickel−rich cathode and lithium metal anode persists critical to the application of quasi−solid high−voltage lithium metal batteries (LMBs). Herein, a chemical/electrochemical response strategy is proposed to construct simultaneously stable cathodic and anodic interfaces relying on the synergistic effect of 1,4,7,10,13,16−hexaoxacyclooctadecane (18C6) and LiNO3. The distinctive [18C6Li]+NO3− cluster modifies electric double layer structure by specific adsorption on the electrode, thereby regulating the interfacial layer composition and construction. The NO3− on electrode preferentially decomposes to improve the interfacial performances, leaving the [18C6Li]+ to cut off the side reaction. Furthermore, the 18C6 coordinates with detrimental transition metal ions from NMC811 cathode and converts into useful clusters alleviating the knock−on effect. Thus, the quasi−solid electrolyte with 18C6 and LiNO3 enables Li||NMC811 coin cell to cycle stably over wide operation temperature (0−55 °C), especially, achieving high capacity retention of 79.2% after 300 cycles at 30 °C. This chemical/electrochemical response strategy projects new insights into the design of smart reactive electrolytes for high−voltage LMBs. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) as emerging material have drawn much attention to apply to the field of water splitting. In this paper, layered NiFe-MIL-53 and nanoflower-like CoFe-MOF-74 were sequentially grown on nickel foam through two-step in-situ growth to construct a MOF-74/MIL-53 heterojunction. On this basis, we used the localized surface plasmon resonance (LSPR) effect of gold nanoparticles (Au NPs) to significantly improve the oxygen evolution reaction performance of MOF-74/MIL-53 heterojunction. Under illumation, the obtained Au-MOF-74/MIL-53 exhibits a lower overpotential of 218 mV, which is far superior to commercial catalyst. The reaction kinetics are significantly enhanced due to the lower charge transfer resistance and the higher electric double layer capacitance. We confirmed the existence of charge transfer between Au NPs and MOFs, and at the same time, the deposition of Au NPs significantly reduced the charge transfer resistance of MOF-74/MIL-53. On the basis of our work, we provide a novel MOF-based electrocatalytic nanocomposite structure for efficient water splitting. • MOF-74/MIL-53 heterojunction is synthesized by in-situ growth method. • Nanoflower-like MOF-74, with more active centers, contributes to mass transfer. • Au-MOF-74/MIL-53 exhibits much lower overpotential than commercial catalysts. • MOF coupled with plasmonic Au NPs can effectively promote water splitting. [ABSTRACT FROM AUTHOR]

Pain‐perceptual Nociceptors (PPNs) in the biological sensory system are critical for the human body to perceive noxious stimuli from the outside world and start appropriate motor responses to minimize potential physical damage. Realization artificial nociceptors with unique synaptic and pain‐perceptual functions of the human nervous system is a key step to develop the next‐generation artificial intelligence systems. Here, an artificial pain‐perceptual device based on an ionic liquid‐polymer solid‐state electrolyte‐gated poly(3‐hexylthiophene) (P3HT) transistor is reported. With the drift motion of mobile ions in the electrolyte layer and the formation of an electric double layer (EDL) at electrolyte/semiconductor interface under an applied electric field, the channel conductance can be tuned progressively to exhibit synaptic weight modulation function. On top of the artificial synaptic functions, the P3HT/electrolyte‐based transistor successfully emulates the pain‐perception process in a biological nociceptor, with all unique features of threshold, no adaptation, sensitization/desensitization, and relaxation. Moreover, the pain conditioning process (i.e., hyperalgesic response, and pain extinction effect) through associative learning is demonstrated using the artificial synaptic transistor, indicating its potential application in bio‐inspired neural systems. [ABSTRACT FROM AUTHOR]

Mathematical models of polyelectrolyte gels are often simplified by assuming the gel is electrically neutral. The rationale behind this assumption is that the thickness of the electric double layer (EDL) at the free surface of the gel is small compared to the size of the gel. Hence, the thin-EDL limit is taken, in which the thickness of the EDL is set to zero. Despite the widespread use of the thin-EDL limit, the solutions in the EDL are rarely computed and shown to match to the solutions for the electrically neutral bulk. The aims of this paper are to study the structure of the EDL and establish the validity of the thin-EDL limit. The model for the gel accounts for phase separation, which gives rise to diffuse interfaces with a thickness described by the Kuhn length. We show that the solutions in the EDL can only be asymptotically matched to the solutions for an electrically neutral bulk, in general, when the Debye length is much smaller than the Kuhn length. If the Debye length is similar to or larger than the Kuhn length, then phase separation can be initiated in the EDL. This phase separation spreads into the bulk of the gel and gives rise to electrically charged layers with different degrees of swelling. Thus, the thin-EDL limit and the assumption of electroneutrality only generally apply when the Debye length is much smaller than the Kuhn length. [ABSTRACT FROM AUTHOR]

Zeta potential refers to the electrokinetic potential present in colloidal systems, exerting significant influence on the diverse properties of nano-drug delivery systems. The impact of the dielectric constant on the zeta potential and charge inversion of highly charged colloidal particles immersed in a variety of solvents spanning from polar, such as water, to nonpolar solvents and in the presence of multivalent salts was investigated through primitive Monte Carlo (MC) model simulations. Zeta potential, ξ , is decreased with the decreasing dielectric constant of the solvent and upon further increase in the salinity and the valency of the salt. At elevated levels of salt, the colloidal particles become overcharged in all solvents. As a result, their apparent charge becomes opposite in sign to the stoichiometric charge. This reversal of charge intensifies until reaching a saturation point with further increase in salinity. [ABSTRACT FROM AUTHOR]

The potential for scale‐up application has been acknowledged by researchers for rechargeable aqueous zinc‐ion batteries (ZIBs). Nonetheless, the progress of the development is significantly impeded due to the instability of the interface between the zinc anode and electrolyte. Herein, efficient and environmentally benign valine (Val) were introduced as aqueous electrolyte additive to stabilize the electrode/electrolyte interface (EEI) via functional groups in additive molecules, thus achieving reversible dendrite‐free zinc anode. The amino groups present in Val molecules have a strong ability to adsorb on the surface of zinc metal, enabling the construction of anchored molecular layer on the surface of zinc anodes. The strongly polar carboxyl groups in Val molecules can act as ion‐transport pumps to capture zinc ions in the electric double layer (EDL) through coordination chemistry. Therefore, this reconstructed EEI could modulate the zinc ion flux and simultaneously suppress side reactions and dendritic growth of Zn. Consequently, a long stable cycling up to 1400 h at a high current density of 20 mA cm−2 is achieved. Additionally, Zn//V2O5 full cell with Val additive exhibit enhanced cyclability, retaining 77 % capacity after 3000 cycles, displaying significant potential in promoting the commercialization of ZIBs. [ABSTRACT FROM AUTHOR]

Despite many additives have been reported for aqueous zinc ion batteries, steric‐hindrance effect of additives and its correlation with Zn2+ solvation structure have been rarely reported. Herein, large‐sized sucrose biomolecule is selected as a paradigm additive, and steric‐hindrance electrolytes (STEs) are developed to investigate the steric‐hindrance effect for solvation structure regulation. Sucrose molecules do not participate in Zn2+ solvation shell, but significantly homogenize the distribution of solvated Zn2+ and enlarge Zn2+ solvation shell with weakened Zn2+−H2O interaction due to the steric‐hindrance effect. More importantly, STEs afford the water‐shielding electric double layer and in situ construct the organic and inorganic hybrid solid electrolyte interface, which effectively boost Zn anode reversibility. Remarkably, Zn//NVO battery presents high capacity of 3.9 mAh ⋅ cm−2 with long cycling stability for over 650 cycles at lean electrolyte of 4.5 μL ⋅ mg−1 and low N/P ratio of 1.5, and the stable operation at wide temperature (−20 °C~+40 °C). [ABSTRACT FROM AUTHOR]

Despite many additives have been reported for aqueous zinc ion batteries, steric‐hindrance effect of additives and its correlation with Zn2+ solvation structure have been rarely reported. Herein, large‐sized sucrose biomolecule is selected as a paradigm additive, and steric‐hindrance electrolytes (STEs) are developed to investigate the steric‐hindrance effect for solvation structure regulation. Sucrose molecules do not participate in Zn2+ solvation shell, but significantly homogenize the distribution of solvated Zn2+ and enlarge Zn2+ solvation shell with weakened Zn2+−H2O interaction due to the steric‐hindrance effect. More importantly, STEs afford the water‐shielding electric double layer and in situ construct the organic and inorganic hybrid solid electrolyte interface, which effectively boost Zn anode reversibility. Remarkably, Zn//NVO battery presents high capacity of 3.9 mAh ⋅ cm−2 with long cycling stability for over 650 cycles at lean electrolyte of 4.5 μL ⋅ mg−1 and low N/P ratio of 1.5, and the stable operation at wide temperature (−20 °C~+40 °C). [ABSTRACT FROM AUTHOR]

This article presents results about the catalytic activity of the cathode in a Direct Methanol Fuel Cell (DMFC) across various operating temperatures. The Dynamic Electrochemical Impedance Spectroscopy (DEIS) technique coupled with a linear current scan was applied for this purpose. An equivalent model based on the thin-film flooded agglomerate model describing the cathode's behaviour was presented, and changes in its parameters were compared with the current load and different temperatures. Studies reveal shifts in cathodic kinetics with increasing load and temperature, alongside changes in resistance curves' slopes. The study identifies 351 K as the most optimal temperature, impacting parameters such as carbon layer resistance, diffusion parameter 1/Yo, and double electric layer capacitance significantly. Differences in slopes of resistance changes for different temperatures were also observed. • Simultaneous impedance measurement of the cathode in a direct methanol fuel cell during changing current density loads. • Obtain changes in the cathode behaviour at different working temperatures. • Slope changes of the polarization resistance curves during an increase in current load for the oxygen reduction reaction. • Obtained polarization resistance values for platinum and carbon support. [ABSTRACT FROM AUTHOR]

The interfacial instability of high‐nickel layered oxides severely plagues practical application of high‐energy quasi‐solid‐state lithium metal batteries (LMBs). Herein, a uniform and highly oxidation‐resistant polymer layer within inner Helmholtz plane is engineered by in situ polymerizing 1‐vinyl‐3‐ethylimidazolium (VEIM) cations preferentially adsorbed on LiNi0.83Co0.11Mn0.06O2 (NCM83) surface, inducing the formation of anion‐derived cathode electrolyte interphase with fast interfacial kinetics. Meanwhile, the copolymerization of [VEIM][BF4] and vinyl ethylene carbonate (VEC) endows P(VEC‐IL) copolymer with the positively‐charged imidazolium moieties, providing positive electric fields to facilitate Li+ transport and desolvation process. Consequently, the Li||NCM83 cells with a cut‐off voltage up to 4.5 V exhibit excellent reversible capacity of 130 mAh g−1 after 1000 cycles at 25 °C and considerable discharge capacity of 134 mAh g−1 without capacity decay after 100 cycles at −20 °C. This work provides deep understanding on tailoring electric double layer by cation specific adsorption for high‐voltage quasi‐solid‐state LMBs. [ABSTRACT FROM AUTHOR]

This work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson–Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profiles were obtained using the method of undetermined coefficients. The Debye–Hückel linearization is used to get an exact solution for the electric potential. The results showed that the Brinkmann number (Br) $({Br})$, Joule heating parameter (J) $(J)$, Debye–Hückel parameter (Κ) $({\rm K})$, Hartmann number (M) $(M)$, electric field (Ez) $({E}_{z})$, and suction/injection parameter (S) $(S)$ have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided to deliver a greater understanding of the influence of relevant parameters on the results achieved. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of three different alkalis, namely ammonia (NH4OH), ethylenediamine (EDA), and tetrabutylammonium hydroxide (TBAOH) on the stability of colloidal silica, with pH controlled within the range of 8–11. As a result, NH4OH greatly promotes the stability of silica sol at first due to the strong solvation ability of NH4+ and then the stability begins to decrease because the electric double layer of silica is compressed. The addition of EDA into silica system leads to a reduction in the stability evidently followed by a slight increase, which can be explained by the cationic bridging effect of the ethylenediammonium cations. Meanwhile, the effect of TBAOH on silica dispersion is analogous to EDA, mainly caused by the hydrophobic and steric effects. The abovementioned relevant stability mechanisms are involved in non-DLVO theory. [ABSTRACT FROM AUTHOR]

Unraveling the origin of Helmholtz capacitance is of paramount importance for understanding the interfacial structure and electrostatic potential distribution of electric double layers (EDL). In this work, we combined the methods of ab initio molecular dynamics and classical molecular dynamics and modeled electrified Cu(100)/electrolyte and graphene/electrolyte interfaces for comparison. It was proposed that the Helmholtz capacitance is composed of three parts connected in series: the usual solvent capacitance, water chemisorption induced capacitance, and Pauling repulsion caused gap capacitance. We found the Helmholtz capacitance of graphene is significantly lower than that of Cu(100), which was attributed to two intrinsic factors. One is that graphene has a wider gap layer at interface, and the other is that graphene is less active for water chemisorption. Finally, based on our findings, we provide suggestions for how to increase the EDL capacitance of graphene-based materials in future work, and we also suggest that the new understanding of the potential distribution across the Helmholtz layer may help explain some experimental phenomena of electrocatalysis. [ABSTRACT FROM AUTHOR]

Copper-mineral oil interfaces are key components of oil-impregnated power transformers and are commonly believed to be one of their weak points. The formation of an electric double layer (EDL) at this interface as a result of charge accumulation and transfer is crucial to its insulating properties, but a molecular-level understanding of this phenomenon remains unclear. To understand this fundamental aspect, we have investigated the effect of different EDLs on the electric potential and interfacial potential barrier between copper and mineral oil by using first principle calculations. Based on the calculations, the EDL is shown to reduce the interfacial potential barrier and enhance the diffusion of oil molecules at the interface when the copper side is negatively charged and the mineral oil side is positively charged. In contrast, when the copper side is positively charged and the mineral oil side is negatively charged, the corresponding EDL can increase the interfacial potential barrier and reduce the diffusion of oil molecules at this interface. Our findings shed light on the relationship between the structure of EDLs and their electrical properties in oil-impregnated power transformers. [ABSTRACT FROM AUTHOR]

An ion detection device that combines a DNA-origami nanopore and a field-effect transistor (FET) was designed and modeled to determine sensitivity of the nanodevice to the local cellular environment. Such devices could be integrated into a live cell, creating an abiotic-biotic interface integrated with semiconductor electronics. A continuum model is used to describe the behavior of ions in an electrolyte solution. The drift-diffusion equations are employed to model the ion distribution, taking into account the electric fields and concentration gradients. This was matched to the results from electric double layer theory to verify applicability of the model to a bio-sensing environment. The FET device combined with the nanopore is shown to have high sensitivity to ion concentration and nanopore geometry, with the electrical double layer behavior governing the device characteristics. A logarithmic relationship was found between ion concentration and a single FET current, generating up to 200 nA of current difference with a small applied bias. [ABSTRACT FROM AUTHOR]

Electron transfer (ET), electric double layer (EDL) charging, and ion transport (IT) are three elementary physicochemical processes in electrochemistry. These processes are coupled with each other in the way that the local reaction environment for the ET is shaped by EDL charging, which is nothing but IT in a nanoscale nonelectroneutral region. Herein, we investigate fingerprints of the coupling between these processes in electrochemical impedance spectroscopy. EDL charging and IT are described uniformly using the Poisson–Nernst–Planck theory, and interfacial ET is described using the Frumkin–Butler–Volmer theory. Different diffusion coefficients for cations and anions (D+ ≠ D−) are considered. Exact analytical expressions are obtained when the potential of zero charge (Epzc), the equilibrium potential of the reaction (Eeq), and electrode potential (EM) are equal. The analytical solution shows that a decoupling treatment is valid only for the case of D+ = D−. Using a new scheme of calculating impedance response at any electrode potential, we observe an inductive loop in the low frequency range, which is a clear impedance fingerprint of the coupling effects. [ABSTRACT FROM AUTHOR]

A general strategy for confined PtCo alloy in a ZIF-67-derived carbon is presented for enhanced electrocatalytic HER. Experimental supports are provided to distinguish whether surface reaction steps or electric double-layer structures play dominant roles in the pH-dependent kinetics of HER. [Display omitted] Zeolitic imidazolate framework-67 (ZIF-67) has been widely used as a precursor to developing efficient PtCo alloy catalysts for hydrogen evolution reaction (HER). However, traditional in-situ pyrolysis strategies involve complicated interface structure modulating processes between ZIF-67 and Pt precursors, challenging large-scale synthesis. Herein, a "pyrolysis etching-confined pyrolysis" approach is developed to design confined PtCo alloy in porous frameworks of onion carbon derived from ZIF-67. The confined PtCo alloy with Pt content of only 5.39 wt% exhibits a distinct HER activity in both acid (η 10 : 5 mV and Tafel: 9 mV dec−1) and basic (η 10 : 33 mV and Tafel: 51 mV dec−1) media and a drastic enhancement in stability. Density functional theory calculations reveal that the strong electronic interaction between Pt and Co allows favorable electron redistribution, which affords a favorable hydrogen spillover on PtCo alloy compared with that of pristine Pt(1 1 1). Operational electrochemical impedance spectroscopy demonstrates that the Faraday reaction process is facilitated under acidic conditions, while the transfer of intermediates through the electric double-layer region under alkaline conditions is accelerated. This work not only offers a universal route for high-performance Pt-based alloy catalysts with metal–organic framework (MOF) precursors but also provides experimental evidence for the role of the electric double layer in electrocatalysis reactions. [ABSTRACT FROM AUTHOR]

The properties of Pickering emulsions is affected by many factors, one of the most typical of which is the ionic environment. Existing studies have mainly focused on the effect of ions in the continuous phase on oil-in-water Pickering emulsions, and usually only single species of ions are studied. The water-in-oil Pickering emulsions are commonly used to encapsulate a variety of water-soluble functional substances, which often contain various of ions. Therefore, it is necessary to study the effect of ions in the internal phase on the properties of inverse Pickering emulsions. The inverse Pickering emulsions with an average droplet size of 100 μm were prepared using hydrophobized calcium carbonate particles. Subsequently, Na+ and Ca2+ were introduced into the internal phase to investigate their effects on the emulsion. The results show that the presence of Na+ can aggravate droplet coalescence, and Ca2+ can cause severe damage to the emulsions and even lead to phase inversion. It was speculated that Na+ can weaken the surface charge of particles by compressing the electric double layer, resulting in lower electrostatic repulsion between particles, thus changing the dispersion state of the particles and ultimately affecting the properties of the emulsion. And Ca2+ can combine with and release stearate from the particle surface through chemical reactions, thus changing the wettability of the particles and resulting in breaking and phase inversion of the emulsions. The present work is informative for the setting of the phase composition and the prediction of stability during the application of inverse Pickering emulsions. [ABSTRACT FROM AUTHOR]

The lithium-ion capacitor (LIC) is a new type of hybrid energy storage device, which combines the advantages of lithium-ion battery and electric double layer capacitor. To achieve efficient and reliable application of LIC in practical scenarios, accurate model and state estimation method are needed. In this work, the electrical behavior of LIC is studied, which is then described by the Thevenin model. A multi-innovation filter- (MIF-) based coestimation method is proposed, in which the multi-innovation linear Kalman filter (MI-LKF) is used for model parameter identification, the multi-innovation cubature Kalman filter (MI-CKF) is used for state of charge estimation, and the multi-innovation extended Kalman filter (MI-EKF) is used for state of health estimation. Compared to traditional methods, this method can significantly improve estimation accuracy by only expanding the innovation used to update the state from a single moment to multiple moments. The experimental results indicate that the estimation errors of SOC and SOH can be constrained within ±0.5%. In addition, the proposed method has good robustness and can achieve high-precision state estimation even in the face of noise interference, uncertain initial values of the algorithm, and uncertain starting operating points. [ABSTRACT FROM AUTHOR]

The carbonate electrolyte chemistry is a primary determinant for the development of high‐voltage lithium metal batteries (LMBs). Unfortunately, their implementation is greatly plagued by sluggish electrode interfacial dynamics and insufficient electrolyte thermodynamic stability. Herein, lithium trifluoroacetate‐lithium nitrate (LiTFA−LiNO3) dual‐salt additive‐reinforced carbonate electrolyte (LTFAN) is proposed for stabilizing high‐voltage LMBs. We reveal that 1) the in situ generated inorganic‐rich electrode‐electrolyte interphase (EEI) enables rapid interfacial dynamics, 2) TFA− preferentially interacts with moisture over PF6− to strengthen the moisture tolerance of designed electrolyte, and 3) NO3− is found to be noticeably enriched at the cathode interface on charging, thus constructing Li+‐enriched, solvent‐coordinated, thermodynamically favorable electric double layer (EDL). The superior moisture tolerance of LTFAN and the thermodynamically stable EDL constructed at cathode interface play a decisive role in upgrading the compatibility of carbonate electrolyte with high‐voltage cathode. The LMBs with LTFAN realize 4.3 V‐NCM523/4.4 V‐NCM622 superior cycling reversibility and excellent rate capability, which is the leading level of documented records for carbonate electrode. [ABSTRACT FROM AUTHOR]

The carbonate electrolyte chemistry is a primary determinant for the development of high‐voltage lithium metal batteries (LMBs). Unfortunately, their implementation is greatly plagued by sluggish electrode interfacial dynamics and insufficient electrolyte thermodynamic stability. Herein, lithium trifluoroacetate‐lithium nitrate (LiTFA−LiNO3) dual‐salt additive‐reinforced carbonate electrolyte (LTFAN) is proposed for stabilizing high‐voltage LMBs. We reveal that 1) the in situ generated inorganic‐rich electrode‐electrolyte interphase (EEI) enables rapid interfacial dynamics, 2) TFA− preferentially interacts with moisture over PF6− to strengthen the moisture tolerance of designed electrolyte, and 3) NO3− is found to be noticeably enriched at the cathode interface on charging, thus constructing Li+‐enriched, solvent‐coordinated, thermodynamically favorable electric double layer (EDL). The superior moisture tolerance of LTFAN and the thermodynamically stable EDL constructed at cathode interface play a decisive role in upgrading the compatibility of carbonate electrolyte with high‐voltage cathode. The LMBs with LTFAN realize 4.3 V‐NCM523/4.4 V‐NCM622 superior cycling reversibility and excellent rate capability, which is the leading level of documented records for carbonate electrode. [ABSTRACT FROM AUTHOR]

A key challenge to apply aqueous zinc‐metal batteries (AZMBs) as next‐generation energy storage devices is to eliminate the adverse reactions of hydrogen evolution, especially in low current. Here, superhydrophobic and ionophilic artificial solid electrolyte interface (HI‐SEI) on zinc anode is proposed and constructed by enhancing roughness and etching ion channels in universal polysiloxane polymer backbones. The HI‐SEI exhibits superhydrophobicity with high contact angle of 151.5° and ionophilicity with low activation energy of 23.97 kJ mol−1. Thus, the HI‐SEI isolates Zn metal and solvent water and promotes desolvation kinetics of Zn2+. Besides, the HI‐SEI alters the double electric layer structure to form a compact layer hardly any adsorbed solvent water, achieving a small nucleation overpotential of 5 mV and low self‐corrosion current density of 0.95 µA cm−2. Moreover, a symmetric cell with HI‐SEI@Zn anode has a cycle life of >1330 h at low current of 0.1 mA cm−2. And a full cell with HI‐SEI@Zn anode and NaV3O8‐1.5H2O cathode provides long cycle life and low capacity degradation (180 mAh g−1 after 1100 cycles). Hopefully, SEI designs based on such a strategy will be able to improve the low‐current cycling performance of the next‐generation AZMBs. [ABSTRACT FROM AUTHOR]

Microbial fuel cells and their related microfluidic systems have emerged as promising greener energy alternatives for the exploitation of avenues related to combined power and wastewater treatment operations. Moreover, the potential for their application in biosensing technology is large. However, while the fundamental principles of science that govern the design and operation of microbial fuel cells (MFCs) and microfluidic microbial fuel cells (MMFCs) are similar to those found in colloid science, the literature shows that current research lacks sufficient reference to the electrostatic and electrokinetic aspects, focusing mostly on aspects related to the architecture, design, anodes, microbial growth and metabolism, and electron transfer mechanisms. In this regard, research is yet to consider MFCs and MMFCs in the context of electrostatic and electrokinetic aspects. In this extensive review, we show, for the first time, the interrelationship of MFCs and MMFCs with electric double layer theory. Consequently, we show how the analytical solution to the mean field Poisson–Boltzmann theory relates to these systems. Moreover, we show the interrelationship between MFC and MMFCs' performance and the electric double layer and the associated electrostatic and electrokinetic phenomena. This extensive review will likely motivate research in this direction. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (ZIBs) are promising candidates for grid‐energy storage due to their safety and cost‐effectiveness. However, the detrimental hydrogen evolution reaction (HER) and dendrite growth on Zn‐metal anodes severely limit their applications. Herein, trace hydrophobic hyamine (HQA, 0.78 mmol L−1) is introduced as an electrolyte additive to improve the electrochemical performance of the Zn anode. Experiments and theoretical calculations revealed that cationic HQA can preferentially adsorb onto the anode surface to inhibit the HER and promote the uniform distribution of Zn ions by forming a water‐lean electric double layer (EDL). Moreover, the oriented adsorption of HQA induced exposure of the Zn (002) plane and prevented dendrite growth. Therefore, the symmetric cells using the HQA‐containing electrolyte exhibited stable cycle performance for more than 1600 h. Even at a high‐density current of 5 mA cm−2, it has a high cumulative capacity of 3250 mAh cm−2. It exhibited an excellent deep‐discharge performance (80%) with a stable cycle for 175 h. The Zn||NH4V4O10 full cell exhibited a high specific capacity and cycle stability at 4.0 A g−1 due to the excellent reversibility of Zn anode. These results provide a new and low‐cost approach for electrolyte design and EDL optimization of high‐performance zinc‐ion batteries. [ABSTRACT FROM AUTHOR]

Highlights: Cetyltrimethylammonium cations can shield the repelling force on anions to attract more anions into electric double layer region during lithium plating process, facilitating the formation of inorganic-rich solid-state electrolyte interphase (SEI). An inorganic-rich (N/F-containing species) structure of SEI can be evidenced by the in-depth analysis. The cycling lifetime of Li||Li symmetric cell in the designed electrolyte can be extended from 500 to 1300 h. Moreover, full cells with a high cathode mass loading of >10 mg cm-2 can be stably cycled over 180 cycles. An anion-rich electric double layer (EDL) region is favorable for fabricating an inorganic-rich solid–electrolyte interphase (SEI) towards stable lithium metal anode in ester electrolyte. Herein, cetyltrimethylammonium bromide (CTAB), a cationic surfactant, is adopted to draw more anions into EDL by ionic interactions that shield the repelling force on anions during lithium plating. In situ electrochemical surface-enhanced Raman spectroscopy results combined with molecular dynamics simulations validate the enrichment of NO3−/FSI− anions in the EDL region due to the positively charged CTA+. In-depth analysis of SEI structure by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results confirmed the formation of the inorganic-rich SEI, which helps improve the kinetics of Li+ transfer, lower the charge transfer activation energy, and homogenize Li deposition. As a result, the Li||Li symmetric cell in the designed electrolyte displays a prolongated cycling time from 500 to 1300 h compared to that in the blank electrolyte at 0.5 mA cm−2 with a capacity of 1 mAh cm−2. Moreover, Li||LiFePO4 and Li||LiCoO2 with a high cathode mass loading of > 10 mg cm−2 can be stably cycled over 180 cycles. [ABSTRACT FROM AUTHOR]

In this study, we have synthesized solid polymer electrolytes using polyvinyl alcohol as a host polymer that has been doped with ionic liquid and ammonium iodide. Impedance spectroscopy revealed that the increase in ionic liquid doping increased the ionic conductivity of the PVA‐NH4I complex. The crystalline nature of the polymeric films was studied using polarized optical microscopy and x‐ray diffraction. To confirm the blending ability of polymer electrolyte, Fourier transform infrared spectroscopy was also used. Finally, a supercapacitor was fabricated using the highest conducting IL‐doped polymer electrolyte which demonstrates a specific capacitance of 97 F/g with a stable efficiency. [ABSTRACT FROM AUTHOR]

The development of high‐mobility neuromorphic transistors is essential to increase signal transmission speed and solve the von Neumann bottleneck issue. Herein, this work proposes cross‐linked Poly(4‐vinylphenol) (c‐PVP) as a dielectric layer to form an electric double layer (EDL), which plays a key role in synaptic transistors, and measure the ratio‐dependent characteristics of cross‐linking agents in c‐PVP. When the ratio of PVP to poly(melamine‐co‐formaldehyde) methylated (PMF) is 10:1, neuromorphic transistors is found to show the best performance with a memory window of 2.2 V and a mobility of 93.4 cm2 V−1 s−1. Fourier‐transform infrared spectroscopy (FT‐IR) results show that the reduction in the concentration of the cross‐linking agent generates more hydroxyl groups within the c‐PVP film. The 10:1 c‐PVP‐based synaptic device has an ultra‐low energy consumption of 15.8 pJ for a single pulse and a maximum paired pulse facilitation (PPF) index value of 291%. Additionally, synaptic characteristics, such as pulse duration time dependent plasticity, pulse intensity dependent plasticity, pulse rate dependent plasticity (SRDP), high band filtering, and short‐term memory (STM) conversion to long‐term memory (LTM), are also described and discussed. These results suggest that c‐PVP/ZnON‐based neuromorphic devices can be promising artificial synapses for memory and learning capabilities. [ABSTRACT FROM AUTHOR]

Electric double layer (EDL) gating is a technique in which ions in an electrolyte modulate the charge transport in an electronic material through electrical field effects. A sub-nanogap capacitor is induced at the interface of electrolyte/semiconductor under the external electrical field and the capacitor has an ultrahigh capacitance density (~µF cm−2). Recently, EDL gating technique, as an interfacial gating, is widely used in two-dimensional (2D) crystals for various sophisticated materials characterization and device applications. This review introduces the EDL-gated transistors based on 2D materials and their applications in the field of bioinspired optoelectronic detection, sensing, logic circuits, and neuromorphic computation. [ABSTRACT FROM AUTHOR]

A self-consistent end-to-end model defining a radio-frequency inductive jet discharge of lowered pressure (13.3–133 Pa) in an undisturbed gas flow and in the presence of a solid body has been proposed. The model comprises three interrelated submodels defining the parts of such a discharge, participating in its interaction with the material treated: the plasma jet, the positive-charge layer formed in the neighborhood of the material, and the double electric layer directly near its surface. A peculiarity of the indicated discharge is that, in its plasma jet, a continuous-medium flow is changed to a free molecular flow, while the flow of charged particles in it satisfies the continuity hypothesis. Because of this, the gasdynamic parameters of the plasma jet are defined using the kinetic Boltzmann equation, the flow of charged particles in the jet and the positive-charge layer are considered in the hydrodynamic approximation, and the double electric layer formed near the surface of the material is defined using the model of a collisionless free molecular flow. [ABSTRACT FROM AUTHOR]

Electrical double-layer (EDL) synaptic transistors based on organic materials exhibit low thermal and chemical stability and are thus incompatible with complementary metal oxide semiconductor (CMOS) processes involving high-temperature operations. This paper proposes organic–inorganic hybrid synaptic transistors using methyl silsesquioxane (MSQ) as the electrolyte. MSQ, derived from the combination of inorganic silsesquioxanes and the organic methyl (−CH3) group, exhibits exceptional thermal and chemical stability, thus ensuring compatibility with CMOS processes. We fabricated Al/MSQ electrolyte/Pt capacitors, exhibiting a substantial capacitance of 1.89 µF/cm2 at 10 Hz. MSQ-based EDL synaptic transistors demonstrated various synaptic behaviors, such as excitatory post-synaptic current, paired-pulse facilitation, signal pass filtering, and spike-number-dependent plasticity. Additionally, we validated synaptic functions such as information storage and synapse weight adjustment, simulating brain synaptic operations through potentiation and depression. Notably, these synaptic operations demonstrated stability over five continuous operation cycles. Lastly, we trained a multi-layer artificial deep neural network (DNN) using a handwritten Modified National Institute of Standards and Technology image dataset. The DNN achieved an impressive recognition rate of 92.28%. The prepared MSQ-based EDL synaptic transistors, with excellent thermal/chemical stability, synaptic functionality, and compatibility with CMOS processes, harbor tremendous potential as materials for next-generation artificial synapse components. [ABSTRACT FROM AUTHOR]

Chitosan, obtained from crustaceans such as crabs and shrimp, has been mainly used in medicine; however, no studies on its use in electronic applications with semiconducting and large storage properties have been reported. Here, we report an n-type semiconducting biomaterial with energy storage properties of 694.4 mJ/m2 consisting of a chitosan nanofiber (ChNF) film with N-type negative resistance. The ChNF generates an alternative-current wave with a frequency of 7.8 MHz at a threshold voltage of 187 MV/m from a direct-current voltage source, with the switching effect of a third-order resistance change. This is due to the Gunn effect, caused by the repeated voltage-induced generation of a strong electric field domain (electric double layer) at the cathode and its disappearance at the anode of the ChNF device. Electron spin resonance spectral analysis showed that conducting electrons of the ChNF were identified as radicals on the aminyl radical, N·H. Paper electronics made from marine products are a great boon to a renewable society. [ABSTRACT FROM AUTHOR]

Contact electrification has attracted interest as a mechanism for generating electrical charges on surfaces. To explore the factors contributing to electrification by droplets impacting the leaf surface, high-speed image capture and current measurements were used to quantitatively characterize the electrical response under different droplet parameters and leaf surface conditions. Upon impact and rebound from the leaf surface, neutral droplets acquire a positive charge. While this electrification phenomenon has been observed previously, there has been limited understanding of the parameters influencing the extent of droplet charging. In this study, we examine the effects of four parameters (droplet size, impact velocity, droplet ion concentration, and various leaf surfaces) on the electrical response signal. The results indicate that this electrification phenomenon is contingent upon the droplet–leaf contact area and droplet ion concentration. We propose a theoretical model based on the electric double layer to elucidate the electrification process. [ABSTRACT FROM AUTHOR]

The electrochemical performance of aqueous zinc metal batteries (AZMBs) is highly dependent on the electric double layer (EDL) properties at Zn electrode/electrolyte interface. Herein, a novel reconfigured EDL is constructed via a double‐charged theanine (TN) additive for super‐stable and deep‐rechargeable AZMBs. Experiments and theoretical computations unravel that the positively charged TN not only serves as preferential anchor to form a water‐poor Helmholtz plane onto the Zn anode, but also its anionic end could coordinate with Zn2+ to tailor the solvation structure in the diffusion layer and further reconstruct the inner H‐bonds networks, thus effectively guiding uniform Zn deposition and suppressing the water‐induced side reactions. Consequently, the Zn//Zn cells acquire outstanding cycling stabilities of nearly 800 h at a high depth of discharge of 80%. Moreover, the Zn//VOX full cells deliver substantial capacity retention (94.12% after 1400 cycles at 2 A g−1) under practical conditions. Importantly, the designed 2.7 Ah Zn//VOX pouch cell harvests a recorded energy density of 42.3 Wh Kgcell−1 and 79.5 Wh Lcell–1, with a remarkable capacity retention of 85.93% after 220 cycles at 50 mA g−1. This innovative design concept to reshape the EDL chemistry would inject fresh vitality into developing advanced AZMBs and beyond. [ABSTRACT FROM AUTHOR]

A new reactive force field based on quantum mechanical data for describing formation of the Zn electrode‐electrolyte interface (EEI) chemistry in aqueous zinc‐ion batteries (ZIBs) is developed. This is the first demonstration in which Reactive Molecular Dynamics (RMD) simulation is used to follow the Zn reduction and anode structural evolution at the EEI. It is found that under axial pressure, Zn dendrite formation is inhibited. This is associated with accelerated ion transport and reduction while increasing preference towards horizontal (002) plane growth. Pressure‐induced desolvation of Zn ions within the electric double layer, which promotes faster reduction kinetics is observed. It is found that axial pressure stabilizes adatoms on the (002) plane by decreasing axial atom stress during nucleation and by increasing favorable lateral adatom diffusion, which reduces atomic scale dendrite formation. Finally, these are confirmed results by experimental characterization and electrochemical tests. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc‐ion batteries (ZIBs) are threatened by the cathode dissolution and anode corrosion/dendrites, resulting in poor reversibility. Here, a multifunctional electrolyte is developed to regulate the cathode, anode interface, and solvation by introducing a low‐cost diethylene glycol monomethyl ether (DGME). The DGME can modulate the primary solvation sheath (PSS) of the hydrated Zn2+ and destroy the original hydrogen bond network of water, while the electric double layer (EDL) interface is reconstructed by the adsorption of DGME, which guides the uniform deposition of Zn2+ on the (002) crystal plane. Simultaneously, the DGME also effectively inhibits the dissolution of VO2 and enhances the reaction kinetics. As a proof of concept, the Zn//Cu cells deliver 2000 cycles with an ultrahigh coulombic efficiency (CE) of 99.6%. Additionally, the multifunctional electrolyte significantly improves the multiple performance of Zn//VO2 full cells. The low‐cost and multifunctional electrolyte can be readily applied to ZIBs, demonstrating its practical versatility. [ABSTRACT FROM AUTHOR]

Converting CO2 to valuable chemicals at ambient conditions has been a topic of great interest due to the large impact of CO2 on global warming. Electrochemical CO2 reduction reaction (CRR) has been considered an effective method to produce valuable products at ambient conditions. Recently, there has been a special focus toward C2+ products, such as C2H4, C2H5OH, or C3H7OH, which have higher energy densities and large applications in chemical industries. Copper surfaces, especially those derived from its oxidized variant, have been experimentally found to be selective for C2 products. In this mini-review, we delve into the recent advances in theoretical calculations for molecular level understanding of the key step of C2 production, the carbon-carbon (CC) coupling reaction. We discuss various methods that have been developed to model the complex electrode surface, including the change in electrode potential, the effect of electrolytes, and intertwining reaction intermediates. We also present a detailed evaluation concerning the errors induced by the different approximations and the importance of solvation and asymmetric reaction environments for CC coupling. Lastly, we summarize with an outlook and possible future research direction, such as simulating experimental observables for vibrational and X-ray absorption spectra at electrode working conditions. [ABSTRACT FROM AUTHOR]

Fractured porous media is of great significance to the exploration and development of unconventional reservoirs. In this paper, a fractal model for permeability through micro-fractured porous media with consideration of the electric double layer (EDL) effect is proposed based on the fractal theory. The present model indicates that the permeability is a function of the electrokinetic parameters and micro-structural parameters of fractured porous media, and each parameter has a clear physical meaning, the results from the proposed model are found to be in good agreement with experimental data. Moreover, factors influencing the permeability are also analyzed in detail. The results indicate that the more obvious EDL effects will lead to permeability becoming lower. The present fractal model for the permeability with the EDL effect can provide guidance for tight reservoir development or other micro-porous media transportation. [ABSTRACT FROM AUTHOR]

We report the results of constant-potential molecular dynamics simulations of the double layer interface between molten 2LiF–BeF2 (FLiBe) and 23LiF–6NaF–21KF (FLiNaK) fluoride mixtures and idealized solid electrodes. Employing methods similar to those used in studies of chloride double layers, we compute the structure and differential capacitance of molten fluoride electric double layers as a function of applied voltage. The role of molten salt structure is probed through comparisons between FLiBe and FLiNaK, which serve as models for strong and weak associate-forming salts, respectively. In FLiBe, screening involves changes in Be–F–Be angles and alignment of the oligomers parallel to the electrode, while in FLiNaK, the electric field is screened mainly by rearrangement of individual ions, predominantly the polarizable potassium cation. [ABSTRACT FROM AUTHOR]

We use 1H, 2H, and 7Li nuclear magnetic resonance to investigate local and diffusive dynamics of LiCl-7H2O and LiCl-7D2O solutions in pristine and functionalized silica nanopores in a component-selective manner. Recently, we showed that the solution dynamics become slower when the diameter of the pristine pores is reduced. Here, we determine the effects of (aminopropyl)triethoxysilane and dye surface functionalizations on the motions of the water molecules and lithium ions from ambient temperatures down to the glass transition. The local and diffusive solution dynamics are similar in both functionalized pores but, on average, slower than in pristine pores with comparable diameters. When the exchange between different confinement regions is sufficiently slow at reduced temperatures, bimodal water and lithium dynamics may be observed. We attribute this bimodality to bulk-like motion in the pore centers and slowed-down motion at the pore walls. For the lithium ions, a bimodality observed in the pristine pores is absent in the functionalized ones. We conjecture that the steric hindrance and electrostatic interactions associated with the grafted functional groups interfere with the formation of a defined electric double layer, while the enhanced surface roughness and unequal charge distribution result in overall slower dynamics. Thus, the nature of the walls is an important parameter for the solution dynamics. Thereby, in situ measurements of the pH value inside the silica pores using the grafted dye molecules reveal that observed changes in the pH value in response to the surface functionalization are of limited relevance for the water reorientation. [ABSTRACT FROM AUTHOR]

The interfacial structure of a super-concentration LiNO3 aqueous electrolyte was studied using non-resonant second harmonic generation (SHG) and heterodyne-detected SHG spectra. First, we investigated the electric double layer structure at the air/LiNO3 interface. As the concentration of LiNO3 increased, the SHG intensity first increased and then remained unchanged, while the SHG phase changed by about 5°. These results reveal that there was only a small amount of NO3− at the interface. The increase of the SHG intensity resulted from the thickening of the interfacial water molecular layer. In addition, we studied the broadening mechanism of the electrochemical stability window (ESW) for the super-concentrated LiNO3 aqueous electrolyte. During cyclic voltammetry scanning, the potential-dependent SHG curves of the Pt/LiNO3 interface verify that at the cathodic end of the ESW, as the concentration of LiNO3 increased, the orientation angle θ of Pt–H changed less and the number density Ns of Pt–H gradually decreased, which indicates the decrease of the number of adsorbed H atoms on the Pt electrode surface. Therefore, the decrease of the number of free water molecules on the Pt electrode surface resulted in an expanded ESW. [ABSTRACT FROM AUTHOR]

Highlights: Electric double-layer regulation enabled by an ultrathin multifunctional solid electrolyte interphase layer with zincophilicity and rapid transport kinetics. Lowered potential drop over the Helmholtz layer and suppressed diffuse layer. Inhibited side reactions and uniform zinc deposition. The practical application of aqueous zinc-ion batteries for large-grid scale systems is still hindered by uncontrolled zinc dendrite and side reactions. Regulating the electrical double layer via the electrode/electrolyte interface layer is an effective strategy to improve the stability of Zn anodes. Herein, we report an ultrathin zincophilic ZnS layer as a model regulator. At a given cycling current, the cell with Zn@ZnS electrode displays a lower potential drop over the Helmholtz layer (stern layer) and a suppressed diffuse layer, indicating the regulated charge distribution and decreased electric double layer repulsion force. Boosted zinc adsorption sites are also expected as proved by the enhanced electric double-layer capacitance. Consequently, the symmetric cell with the ZnS protection layer can stably cycle for around 3,000 h at 1 mA cm−2 with a lower overpotential of 25 mV. When coupled with an I2/AC cathode, the cell demonstrates a high rate performance of 160 mAh g−1 at 0.1 A g−1 and long cycling stability of over 10,000 cycles at 10 A g−1. The Zn||MnO2 also sustains both high capacity and long cycling stability of 130 mAh g−1 after 1,200 cycles at 0.5 A g−1. [ABSTRACT FROM AUTHOR]