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The enormous interest in developing powerful Li‐based batteries leads to a boost in materials research. Though Li–sulfur batteries offer very high energy densities, the nature of Li‐ion dynamics in the final discharge product Li2S$\left(\text{Li}\right)_{2} \text{S}$ has not been fully understood yet. While nanocrystalline Li2S$\left(\text{Li}\right)_{2} \text{S}$ shows enhanced ion dynamics compared to its coarse‐grained counterpart, the interaction of Li2S$\left(\text{Li}\right)_{2} \text{S}$ with another binary such as LiI seems to be rather unexplored. Herein, an equimolar mixture of Li2S$\left(\text{Li}\right)_{2} \text{S}$ and LiI is treated in a high‐energy ball mill, and both the overall and local structural changes are studied by X‐ray powder diffraction and 6,7Li$^{6,7} \text{Li}$ nuclear magnetic resonance (NMR), respectively. Besides the formation of amorphous regions, evidences are found for the generation of anion‐mixed sites that give rise to facile Li+$^{+}$ exchange on the 2D exchange NMR timescale. Compared to a coarse‐grained reference sample, the overall (bulk) ionic conductivity of nanocrystalline Li2S$\left(\text{Li}\right)_{2} \text{S}$‐LiI increases by two orders of magnitude. Besides the anion‐mixing effect, this increase benefits from nanosize effects that include the formation of defect‐rich interfacial regions. NMR relaxation measurements fully support this result and reveal heterogeneous dynamics with lower activation energies for both the localized hopping processes and long‐range ion transport in nm‐sized Li2S$\left(\text{Li}\right)_{2} \text{S}$‐LiI. [ABSTRACT FROM AUTHOR]

Highlights Transient response plays a crucial role as a performance indicator for organic electrochemical transistors (OECTs), particularly in their application in high-speed logic circuits and neuromorphic computing systems. This review presents a systematic overview on the fundamental principles underlying OECT transient responses, emphasizing the essential roles of transient electron and ion dynamics, as well as structural evolution, in both volatile and non-volatile behaviors. We also discuss the materials, morphology, device structure strategies on optimizing transient responses.

Introduction: Cusp ion dispersion signatures reflect properties of remote magnetic reconnection. Since the cusp is easier to observe in situ compared to the reconnection x-line, ion dispersions provide key insight on whether reconnection is variable in space and time. This study is motivated by a specific dispersion signature having two ion populations separated in energy but not space. These are known as overlapping dispersions because when observed by low-Earth orbiting satellites traversing the cusp, they appear as two dispersed ion populations overlapping in magnetic latitudes. Overlapping dispersion signatures have been observed for all interplanetary magnetic field (IMF) orientations and have been associated with multiple reconnection processes, but the three-dimensional magnetic reconnection topology and particle trajectories have not been examined. Methods: Forward particle tracing using the GAMERA-CHIMP global magnetohydrodynamic (MHD) with test particle framework is carried out to construct ion dispersion signatures throughout the cusp. Under idealized solar wind driving with steady purely southward IMF, both standard and overlapping dispersions are found. Results: Analysis of the test particle trajectories shows that the higher energy population of the overlapping dispersion travels along the axis of a flux rope before heading into the cusp, whereas the lower energy population goes directly into the cusp. Furthermore, the overlapping dispersions observed by the synthetic satellites compare well to Defense Meteorological Satellite Program (DMSP) F16 observations during strongly southward IMF. Discussion: It is thus concluded that during strongly southward IMF, cusp-entering particles interacting with a magnetopause flux rope (generated by secondary reconnection) is one way to produce an overlapping dispersion. This study lays the groundwork for the forthcoming NASA Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) mission, which will connect the cusp to the magnetosphere--discovering how spatial or temporal variations in magnetic reconnection drive cusp dynamics. The expected launch of TRACERS is in 2025. [ABSTRACT FROM AUTHOR]

The blend of solid polymer electrolyte (SPE) has drawn tremendous attention due to its applications in energy devices. SPE prepared from a mixture of poly(vinylidene fluoride) (PVDF) and poly(ethylene oxide) (PEO) polymers at a 4:1 weight ratio with 20 mM KBr salt shows very high thermal and mechanical stability. However, this composition of SPE exhibits poor ionic conductivity due to its low salt solubility in the polymer matrix. We hypothesize that the increase in salt solubility may lead to an improvement in ionic conductivity. In this study, we have systematically investigated the effect of gamma and high-energy ion beam irradiation on the salt solubility, ion dynamics, and relaxation properties of PVDF-PEO-based SPE. XRD profiles and SEM micrographs of SPE clearly indicate the enhancement of salt solubility with increasing gamma irradiation doses and found complete solubility of KBr salt within the polymer matrix for doses above 50 kGy. The impedance spectroscopy study showed that the dc conductivity was enhanced eight times that of the pristine sample obtained from the Nyquist plot. A new carbonyl (C = O) functional group is generated due to gamma irradiation, which facilitates salt dissociation, as revealed from FTIR studies. The maximum conductivity was found at a gamma dose of 100 kGy. Models such as the Universal Power Law model (Almond and West model), the Poisson–Nernst–Planck (PNP) model, Havrilliak–Nigami (HN), and Kohlrausch–Williams–Watts (KWW) were employed to explore ion dynamics from ac conductivity and modulus spectra. These models provide bulk resistance, double-layer capacitance, hopping frequency, dielectric, and conductivity relaxation time of gamma-irradiated SPEs. An ion conduction mechanism through the polymer matrix has been proposed based on the experimental results of the high-energy-irradiated SPE. [ABSTRACT FROM AUTHOR]

Highlights: Transient response plays a crucial role as a performance indicator for organic electrochemical transistors (OECTs), particularly in their application in high-speed logic circuits and neuromorphic computing systems. This review presents a systematic overview on the fundamental principles underlying OECT transient responses, emphasizing the essential roles of transient electron and ion dynamics, as well as structural evolution, in both volatile and non-volatile behaviors. We also discuss the materials, morphology, device structure strategies on optimizing transient responses. The rapid development of organic electrochemical transistors (OECTs) has ushered in a new era in organic electronics, distinguishing itself through its application in a variety of domains, from high-speed logic circuits to sensitive biosensors, and neuromorphic devices like artificial synapses and organic electrochemical random-access memories. Despite recent strides in enhancing OECT performance, driven by the demand for superior transient response capabilities, a comprehensive understanding of the complex interplay between charge and ion transport, alongside electron–ion interactions, as well as the optimization strategies, remains elusive. This review aims to bridge this gap by providing a systematic overview on the fundamental working principles of OECT transient responses, emphasizing advancements in device physics and optimization approaches. We review the critical aspect of transient ion dynamics in both volatile and non-volatile applications, as well as the impact of materials, morphology, device structure strategies on optimizing transient responses. This paper not only offers a detailed overview of the current state of the art, but also identifies promising avenues for future research, aiming to drive future performance advancements in diversified applications. [ABSTRACT FROM AUTHOR]

This paper reports the comparative studies on polymer gel electrolytes (PGEs) comprising liquid electrolytes of the triflate salts of Li, Na, and Mg in tetraethylene glycol dimethyl ether (TEGDME) solvent and poly(vinylidene fluoride-hexafluoropropylene) and poly(vinylpyrroliddone), i.e., PVdF(HFP)/PVP polymer blend matrix. The effect of different cations is investigated using various structural, thermal, and electrochemical techniques. The ionic conductivity and the ion-transport behavior are investigated using electrochemical impedance spectroscopy (EIS) over wide range of frequency. The XRD studies indicate the prominent structural variation after the immobilization of Li, Na, and Mg triflate salts in the PVdF(HFP)/PVP/TEGDME matrix. The Li+ ion conducting PGE composition displays the maximum room temperature ionic conductivity of ~ 6.5 × 10−3 S cm−1. Further, it exhibits a high dielectric constant value and superior ion-dynamics as compared to Na+ and Mg2+ based electrolytes. The PGEs display translational ion-dynamics and conductivity relaxation clubbed with polarizing effects and long-range mobility/migration of the cations (Na+, Mg2+, Li+). The morphological and structural studies reveal that Li+ ion conducting PGE offers a porous structure with smooth surface facilitating faster ionic motion. The PGEs possess considerable electrochemical stability window (≥ 4.0 V) and thermal stability, which prove them worthy for developing ion-batteries, super-capacitors and other next-generation electrochemical devices. [ABSTRACT FROM AUTHOR]

The reversal potential refers to the membrane potential at which the net current flow through a channel reverses direction. The reversal potential is determined by transmembrane ion gradients and, in turn, determines how the channel's activity will affect the membrane potential. Traditional investigation into the reversal potential of inhibitory ligand-gated ion channels (EInh) has relied upon the activation of endogenous receptors, such as the GABA-A receptor (GABAAR). There are, however, challenges associated with activating endogenous receptors, including agonist delivery, isolating channel responses, and the effects of receptor saturation and desensitization. Here, we demonstrate the utility of using a light-gated anion channel, stGtACR2, to probe EInh in the rodent brain. Using mice of both sexes, we demonstrate that the properties of this optically activated channel make it a suitable proxy for studying GABAAR receptor-mediated inhibition. We validate this agonist-independent optogenetic strategy in vitro and in vivo and further show how it can accurately capture differences in EInh dynamics following manipulations of endogenous ion fluxes. This allows us to explore distinct resting EInh differences across genetically defined neuronal subpopulations. Using this approach to challenge ion homeostasis mechanisms in neurons, we uncover cell-specific EInh dynamics that are supported by the differential expression of endogenous ion handling mechanisms. Our findings therefore establish an effective optical strategy for revealing novel aspects of inhibitory reversal potentials and thereby expand the repertoire of optogenetics. [ABSTRACT FROM AUTHOR]

The ion foreshock is highly dynamic, disturbing the bow shock and the magnetosphere‐ionosphere system. To forecast foreshock‐driven space weather effects, it is necessary to model foreshock ions as a function of upstream shock parameters. Case studies in the accompanying paper show that magnetosheath ions sometimes exhibit strong field‐aligned asymmetry toward the upstream direction, which may be responsible for enhancing magnetosheath leakage and therefore foreshock ion density. To understand the conditions leading to such asymmetry and the potential for enhanced leakage, we perform case studies and a statistical study of magnetosheath and foreshock region data surrounding ∼500 Time History of Events and Macroscale Interactions during Substorms mission bow shock crossings. We quantify the asymmetry using the heat flux along the field‐aligned direction. We show that the strong field‐aligned heat flux persists across the entire magnetosheath from the magnetopause to the bow shock. Ion distribution functions reveal that the strong heat flux is caused by a secondary thermal population. We find that stronger asymmetry events exhibit heat flux preferentially toward the upstream direction near the bow shock and occur under larger IMF strength and larger solar wind dynamic pressure and/or energy flux. Additionally, we show that near the bow shock, magnetosheath leakage is a significant contributor to foreshock ions, and through enhancing the leakage the magnetosheath ion asymmetry can modulate the foreshock ion velocity and density. Our results imply that likely due to field line draping and compression against the magnetopause that leads to a directional mirror force, modeling the foreshock ions necessitates a more global accounting of downstream conditions. Key Points: Ion field‐aligned asymmetry persists across the magnetosheath, caused by a secondary thermal population of magnetosheath ionsLarger IMF strength and solar wind dynamic pressure and/or energy flux favor stronger field‐aligned asymmetryNear the bow shock, the foreshock ion velocity and density are modulated by the magnetosheath ion field‐aligned asymmetry [ABSTRACT FROM AUTHOR]

Abstract Carbon has been widely utilized as electrode in electrochemical energy storage, relying on the interaction between ions and electrode. The performance of a carbon electrode is determined by a variety of factors including the structural features of carbon material and the behavior of ions adsorbed on the carbon surface in the specific environment. As the fundamental unit of graphitic carbons, graphene has been employed as a model to understand the energy storage mechanism of carbon materials through various experimental and computational methods, ex‐situ or in‐situ. In this article, we provide a succinct overview of the state‐of‐the‐art proceedings on the ion storage mechanism on graphene. Topics include the structure engineering of carbons, electric gating effect of ions, ion dynamics on the interface or in the confined space, and specifically lithium‐ion storage/reaction on graphene. Our aim is to facilitate the understanding of electrochemistry on carbon electrodes.

ABSTRACTThe control of ion transport by responding to stimulus is a necessary condition for the existence of life. Bioinspired iontronics could enable anomalous ion dynamics in the nanoconfined spaces, creating many efficient energy systems and neuromorphic in-sensor computing networks. Unlike traditional electronics based on von Neumann computing architecture, the Boolean logic computing based on the iontronics could avoid complex wiring with higher energy efficiency and programmable neuromorphic logic. Here, a systematic summary on the state of art in bioinspired iontronics is presented and the stimulus from chemical potentials, electric fields, light, heat, piezo and magnetic fields on ion dynamics are reviewed. Challenges and perspectives are also addressed in the aspects of iontronic integrated systems. It is believed that comprehensive investigations in bioinspired ionic control will accelerate the development on more efficient energy and information flow for the futuristic human-machine interface.

Theoretical analysis has revealed a specific resonance that shares the same condition as Landau resonance, but instead involves wave electromagnetic fields rather than traditionally electrostatic fields. While this resonance, referred to as electromagnetic Landau resonance due to its properties, is considered significant for magnetospheric dynamics, rare reports or evaluations based on observations have been made thus far. Here, we present an event detected by the Magnetospheric Multiscale mission near the dayside magnetopause. During this event, ∼748‐eV protons are observed to be in resonance with a wave. Detailed data analysis demonstrates the resonant velocity closely matches the wave's parallel phase speed, which, combined with the significant work done by wave perpendicular electric field, confirms this interaction as electromagnetic Landau resonance. Further investigation indicates these protons are being secularly accelerated within this resonance. Consequently, our observations provide the first empirical evidence supporting the previously suggested theoretical importance of the electromagnetic Landau resonance. Plain Language Summary: The electromagnetic Landau resonance shares the same resonance condition as the normal Landau resonance, but differs in that it involves the electromagnetic components of wave fields instead of the electrostatic components found in the case of the latter. Although it has been examined in theories and confirmed to occur in space plasmas experimentally, this resonance, especially the accompanying evolution of particle velocity distributions, has yet to be evaluated quantitatively through spacecraft observations. In this paper, we report the first observation of this resonance obtained by the Magnetospheric Multiscale mission near the dayside magnetosphere. In the reported case, protons of ∼400–1,000 eV are found to be in resonance with a wave. A more detailed examination of the observed fields and protons shows the corresponding resonant velocity is nearly identical to the wave's parallel phase speed. This observation, combined with the significant work done by wave perpendicular electric field, conclusively confirms the observed interaction as the electromagnetic Landau resonance. Further investigation indicates the protons are secularly accelerated by the wave via this resonance. Hence, our observations provide empirical evidence supporting the previously suggested theoretical significance of the electromagnetic Landau resonance. Key Points: MMS observations of electromagnetic Landau resonance near the dayside magnetopause are presentedThis resonance follows the same condition as the Landau resonance, but modulates particles via the electromagnetic components of wave fieldsAnalysis of the observed fields and protons provide conclusive evidence for this resonance accelerating protons [ABSTRACT FROM AUTHOR]

The control of ion transport by responding to stimulus is a necessary condition for the existence of life. Bioinspired iontronics could enable anomalous ion dynamics in the nanoconfined spaces, creating many efficient energy systems and neuromorphic in-sensor computing networks. Unlike traditional electronics based on von Neumann computing architecture, the Boolean logic computing based on the iontronics could avoid complex wiring with higher energy efficiency and programmable neuromorphic logic. Here, a systematic summary on the state of art in bioinspired iontronics is presented and the stimulus from chemical potentials, electric fields, light, heat, piezo and magnetic fields on ion dynamics are reviewed. Challenges and perspectives are also addressed in the aspects of iontronic integrated systems. It is believed that comprehensive investigations in bioinspired ionic control will accelerate the development on more efficient energy and information flow for the futuristic human-machine interface. [ABSTRACT FROM AUTHOR]

The ion foreshock, filled with backstreaming foreshock ions, is very dynamic with many transient structures that disturb the bow shock and the magnetosphere‐ionosphere system. It has been shown that foreshock ions can be generated through either solar wind reflection at the bow shock or leakage from the magnetosheath. While solar wind reflection is widely believed to be the dominant generation process, our investigation using Time History of Events and Macroscale Interactions during Substorms mission observations reveals that the relative importance of magnetosheath leakage has been underestimated. We show from case studies that when the magnetosheath ions exhibit field‐aligned anisotropy, a large fraction of them attains sufficient field‐aligned speed to escape upstream, resulting in very high foreshock ion density. The observed foreshock ion density, velocity, phase space density, and distribution function shape are consistent with such an escape or leakage process. Our results suggest that magnetosheath leakage could be a significant contributor to the formation of the ion foreshock. Further characterization of the magnetosheath leakage process is a critical step toward building predictive models of the ion foreshock, a necessary step to better forecast foreshock‐driven space weather effects. Key Points: Using observations of bow shock crossings by Time History of Events and Macroscale Interactions during Substorms mission, we investigate the magnetosheath‐origin foreshock ionsForeshock ion density, velocity, phase space density, and distribution shape are consistent with non‐adiabatic magnetosheath leakageMagnetosheath ion field‐aligned anisotropy could cause leakage to become a dominant source of foreshock ions [ABSTRACT FROM AUTHOR]

Abstract Hybrid organic–inorganic perovskites (HOIPs) are promising candidates for next‐generation photovoltaic materials. However, there is a debate regarding the impact of interactions between the organic center and the surrounding inorganic cage on the solar cell's high diffusion lengths. It remains unclear whether the diffusion mechanism is consistent across various halide perovskite families and how light illumination affects carrier lifetimes. The focus is on ion kinetics of (CH3NH3)PbX3 (X = Br, Cl) perovskite halide single crystals. Muon spectroscopy (μ+SR)is employed to investigate the fluctuations and diffusion of ions via the relaxation of muon spins in local nuclear field environments. Within a temperature range of 30–340 K, ion kinetics are studied with and without white‐light illumination. The results show a temperature shift of the tetragonal‐orthorhombic phase transition on the illuminated samples, as an effect of increased organic molecule fluctuations. This relation is supported by density functional theory (DFT) calculations along the reduction of the nuclear field distribution width between the phase transitions. The analysis shows that, depending on the halide ion, the motional narrowing from H and N nuclear moments represents the molecular fluctuations. The results demonstrate the importance of the halide ion and the effect of illumination on the compound's structural stability and electronic properties.

Heat generated from various sources is inevitably wasted. Thermoelectric generators (TEGs) are suitable for recovering such waste heat because of their simple structure and operating principle. Herein, a zwitterionic (ZI) polymer‐based fully self‐healable ionic TEG is presented. By adjusting the position of the positive and negative moieties of the ZI side chain, the movement of free ions contained in the ionogel can be controlled effectively, thus improving the power factor of TEGs. ZI side chains inside the ionogel provide multiple ionic interaction sites and enable fast self‐healing characteristics at room temperature. Furthermore, a self‐healing electrode composed of liquid metal (LM), waterborne polyurethane (WPU), and polyvinyl alcohol (PVA) is developed for the fully healable TEGs. The overall areal output voltage is effectively improved by connecting 10 legs of p and n thermoelectric gels in series via a self‐healing process. The selectively ion‐boosted, fully self‐healable TEGs developed in this study will open a new horizon for high‐performance ionic TEGs. [ABSTRACT FROM AUTHOR]

Conventional vision systems suffer from lots of data handling between memory and processing units. Inspired by how humans recognize noisy images and the flexible modulation on the timescale of ion dynamics inside an emerging memtransistor, a novel neuromorphic vision system is reported based on the ion‐modulated memtransistors. By controlling the ion‐doping processes under adequate stimuli strengths, both short‐term and long‐term ion dynamics can be utilized to deliver energy‐efficient data processing. When dealing with image reconstructions, the short‐term accumulation effect of the device can help filter noises in a set of received noisy images while enhancing the original pattern information. The increased contrast can help distinguish the actual contents. To demonstrate systematic performances with the reconfiguration of devices, the nonlinear relationship between channel conductance variation and the amplitude of gate pulses into the network‐level simulation is extracted. Also, with the nonvolatile conductance change characteristic, the task of recognizing noisy images is performed to verify the versatility of ion‐modulated memtransistors in the neuromorphic artificial vision systems. An interactive preprint version of the article can be found here: https://doi.org/10.22541/au.167939089.96499861/v1 [ABSTRACT FROM AUTHOR]

Conventional vision systems suffer from lots of data handling between memory and processing units. Inspired by how humans recognize noisy images and the flexible modulation on the timescale of ion dynamics inside an emerging memtransistor, a novel neuromorphic vision system is reported based on the ion‐modulated memtransistors. By controlling the ion‐doping processes under adequate stimuli strengths, both short‐term and long‐term ion dynamics can be utilized to deliver energy‐efficient data processing. When dealing with image reconstructions, the short‐term accumulation effect of the device can help filter noises in a set of received noisy images while enhancing the original pattern information. The increased contrast can help distinguish the actual contents. To demonstrate systematic performances with the reconfiguration of devices, the nonlinear relationship between channel conductance variation and the amplitude of gate pulses into the network‐level simulation is extracted. Also, with the nonvolatile conductance change characteristic, the task of recognizing noisy images is performed to verify the versatility of ion‐modulated memtransistors in the neuromorphic artificial vision systems. An interactive preprint version of the article can be found here: https://doi.org/10.22541/au.167939089.96499861/v1

Simple Summary: Intrinsically Disordered Proteins (IDPs) are particularly sensitive to changes in chemical environmental conditions. Changes in this environment lead to alterations of their normal functions. We introduce the concept of a Time-Resolved Radial Distribution Function (TRRDF). TRRDFs are able to characterize the local environment dynamics in simulations around dynamically changing IDPs. TRRDFs are implemented and available in our open-source Python package SPEADI. We use SPEADI to characterize the dynamic distribution of ions around two IDPs Alpha-Synuclein (AS) and Humanin (HN) from Molecular Dynamics (MD) simulations. We analyze and explore the local ion–residue interactions that play an important role in the structures and behaviors of IDPs. The disordered nature of Intrinsically Disordered Proteins (IDPs) makes their structural ensembles particularly susceptible to changes in chemical environmental conditions, often leading to an alteration of their normal functions. A Radial Distribution Function (RDF) is considered a standard method for characterizing the chemical environment surrounding particles during atomistic simulations, commonly averaged over an entire or part of a trajectory. Given their high structural variability, such averaged information might not be reliable for IDPs. We introduce the Time-Resolved Radial Distribution Function (TRRDF), implemented in our open-source Python package SPEADI, which is able to characterize dynamic environments around IDPs. We use SPEADI to characterize the dynamic distribution of ions around the IDPs Alpha-Synuclein (AS) and Humanin (HN) from Molecular Dynamics (MD) simulations, and some of their selected mutants, showing that local ion–residue interactions play an important role in the structures and behaviors of IDPs. [ABSTRACT FROM AUTHOR]

Energetic particle injections, usually observed as sudden flux enhancements of charged particles from tens to hundreds of keV, are one of the main mechanisms for ring current enhancement. In this study, we statistically analyzed the influence of dispersionless injections on Earth's ring current based on the measurements of radiation belt storm probes ion composition experiment onboard Van Allen Probes from 2013 to 2019. We identified 813 dispersionless proton injection events, which are mainly in the pre‐midnight sector. With a greater SuperMAG electrojet index (SME), the observed injections extend to lower L shells. Meanwhile, Helium (He+) and oxygen (O+) ions experience almost simultaneous injections with protons. Superposed epoch results show that ion energy densities enhance significantly after injections. As SMEmax increases, the ring current energy densities of all three species are increasing, and the magnitude of the enhancements, defined as the ratio of the energy densities after and before the injection, hardly changes for protons (∼2.0) and He+ ions (∼2.0) but increases for O+ ions (2.6 and 3.0 for SMEmax < 1,000 nT and SMEmax ≥ 1,000 nT, respectively), suggesting the contribution of O+ ions to ring current becomes more significant during super substorms. With proton injections, the dawn‐dusk electric field is enhanced sharply to twice as large as before. Simultaneously, there is a dip followed by gradual dipolarization of the magnetic fields. Moreover, particle anisotropies increase following ion injections, which may generate electromagnetic ion cyclotron waves. These statistical results indicate that ion injections during substorms contribute significantly to the ring current. Plain Language Summary: Ring current is one of the most significant current systems in the Earth's magnetosphere, and substorm injections are major mechanisms for ring current enhancement. Dispersionless injections are considered to be in the source region, characterized by simultaneous sudden flux enhancements of charged particles from tens to hundreds of keV. Using data from Van Allen Probes, we statistically surveyed the impact of dispersionless injections on the ring current from 2013 to 2019. We found that injection events are mainly at the pre‐midnight sector, and the depth increases with stronger substorms. Along with proton injections, He+ and O+ ions are also simultaneously injected into the ring current region. The ion injections increase the energy densities of the ring current significantly, with energy densities of H+ and He+ ions increasing to twice as much as before and O+ ions rising to over 2.6 times the level before injections. Following ion injections, the configurations of the electric and magnetic fields in the ring current region change, and particle anisotropies that may generate electromagnetic ion cyclotron waves increase, leading to the loss or acceleration of inner magnetospheric particles. Key Points: We analyze the energetic particle dispersionless injections inside the geosynchronous orbit from 2013 to 2019 through RBSP observationsThe contributions of H+, He+, and O+ ion injections on the energy densities of ring current are investigated under different conditionsThe configuration of the electromagnetic fields and particle anisotropies in the ring current region change with ion injections [ABSTRACT FROM AUTHOR]

Organic mixed ionic-electronic conductors (OMIECs) have garnered significant attention due to their capacity to transport both ions and electrons, making them ideal for applications in energy storage, neuromorphics, and bioelectronics. However, charge compensation mechanisms during the polymer redox process remain poorly understood, and are often oversimplified as single-ion injection with little attention to counterion effects. To advance understanding and design strategies toward next-generation OMIEC systems, a series of p-channel carboxylated mixed conductors is investigated. Varying side-chain functionality, distinctive swelling character is uncovered during electrochemical doping/dedoping with model chao-/kosmotropic electrolytes. Carboxylic acid functionalized polymers demonstrate strong deswelling and mass reduction during doping, indicating cation expulsion, while ethoxycarbonyl counterparts exhibit prominent mass increase, pointing to an anion-driven doping mechanism. By employing operando grazing incidence X-ray fluorescence (GIXRF), it is revealed that the carboxyl functionalized polymer engages in robust cation interaction, whereas ester functionalization shifts the mechanism towards no cation involvement. It is demonstrated that cations are pivotal in mitigating swelling by counterbalancing anions, enabling efficient anion uptake without compromising performance. These findings underscore the transformative influence of functionality-driven factors and side-chain chemistry in governing ion dynamics and conduction, providing new frameworks for designing OMIECs with enhanced performance and reduced swelling., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

High-accuracy neuromorphic devices with adaptive weight adjustment are crucial for high-performance computing. However, limited studies have been conducted on achieving selective and linear synaptic weight updates without changing electrical pulses. Herein, we propose high-accuracy and self-adaptive artificial synapses based on tunable and flexible MXene energy storage devices. These synapses can be adjusted adaptively depending on the stored weight value to mitigate time and energy loss resulting from recalculation. The resistance can be used to effectively regulate the accumulation and dissipation of ions in single devices, without changing the external pulse stimulation or preprogramming, to ensure selective and linear synaptic weight updates. The feasibility of the proposed neural network based on the synapses of flexible energy devices was investigated through training and machine learning. The results indicated that the device achieved a recognition accuracy of ∼95% for various neural network calculation tasks such as numeric classification. [ABSTRACT FROM AUTHOR]

The Poly(ethylene oxide) (PEO)-based polymer electrolytes exhibit the drawbacks of high crystallinity and low ionic conductivity (<10−5 S m−1), which significantly restrict their application in solid-state lithium metal batteries. This study presents the bismuth metal-organic frameworks (MOFs) as a PEO-based electrolyte filler, incorporating frustrated Lewis acid-base pairs, which is formed in-situ through the coordination of ellagic acid (EA) and bismuth ions (Bi3+). The simultaneous presence of Lewis acids (unsaturated Bi3+) and bases (free nitrate, NO 3 −) in the MOFs, which effectively transfers and transports the lithium ions through the synergistic interaction based on the polymer matrix and the lithium salts, resulting in the high durable solid-state lithium batteries. Meanwhile, NO 3 − can further promote the dissociation of lithium ion (Li+) and the formation of inorganic solid electrolyte interfaces (SEIs) with lithium metal, which is conducive to the dynamic repair of SEIs. Characterizations and calculations show that Bi-MOFs promote the increase of composite ionic conductivity (6.4 × 10−4 S cm−1, 60 °C) and lithium transference number (0.52, 60 °C). At a current density of 0.4 mA cm−2, the assembled Li–Li symmetric battery can be continuously cycled for more than 500 h. This strategy opens a new window for improvement of solid-state electrolyte performance. The frustrated Lewis pair is generated in-situ in Bi-MOFs, and its unsaturated metal cations and free anions act synergistically on polymer matrix and lithium salt, which accelerates the free diffusion of Li+, and NO 3 − can dynamically repair the lithium-electrolyte interface, thus achieving near 5000 h dendrite-free lithium cycle. [Display omitted] • Bi-MOF doped into PEO electrolyte boosts Li-ion conductivity. • Frustrated Lewis pairs enhance Li salt dissociation, t + to 0.52. • The composite electrolyte exhibits enhanced mechanical strength which inhibits Li dendrite growth. • CSPE-0.1BiICP formula improves all-solid-state battery cycling performance. [ABSTRACT FROM AUTHOR]

Siyu He,1 Kornkanok Tripanpitak,2 Yu Yoshida,2 Shozo Takamatsu,3 Shao Ying Huang,4 Wenwei Yu2,5 1Graduate School of Engineering, Chiba University, Chiba, Japan; 2Graduate School of Science and Engineering, Chiba University, Chiba, Japan; 3Omron Healthcare Co., Ltd, Kyoto, Japan; 4Engineering Product Development, Singapore University of Technology and Design, Singapore; 5Center for Frontier Medical Engineering, Chiba University, Chiba, JapanCorrespondence: Wenwei YuGraduate School of Science and Technology, Building1-501, Yayoi-Cho, Inage-Ku, Chiba, 263-8522, JapanTel/Fax +81 043 290 3231Email yuwill@faculty.chiba-u.jpPurpose: Few investigations have been conducted on the selective stimulation of small-radius unmyelinated C nerves (C), which are critical to both the recovery of damaged nerves and pain suppression. The purpose of this study is to understand how an anodal pulse in an anodal-first stimulation could improve C-selectivity over myelinated nociceptive Aδ nerves (Aδ) and to further clarify the landscape of the solution space.Materials and Methods: An adapted Hodgkin–Huxley (HH) model and the McIntyre–Richardson–Grill (MRG) model were used for modeling C and Aδ, respectively, to analyze the underlying ion dynamics and the influence of relevant stimulation waveforms, including monopolar, polarity-symmetric, and asymmetric pulses.Results: The results showed that polarity asymmetric waveforms with preceding anodal stimulations benefit C-selectivity the most, underlain by the decrease in the potassium ion current of C.Conclusion: The optimal parameters for C-selectivity have been identified in the low-frequency band, remarkably benefiting the design of selective stimulation waveforms for the recovery of damaged nerves and pain management.Keywords: anodal-first stimulation, C-selectivity, ion dynamics, polarity-asymmetric waveforms

Solid electrolyte composites between organic ionic plastic crystals (OIPCs) and polymers can potentially show enhanced mechanical properties and ion conduction. These properties can be determined by the formation of interfacial regions which affect the structure, thermal properties, and ion transport of the composite material. Here we studied the properties of composites between the OIPC hexamethylguanidinium bis(fluorosulfonyl)imide (HMGFSI) and acrylate polymer nanoparticles functionalised with lithium, using various techniques including solid-state NMR spectroscopy. An enhancement in ionic conductivity of three orders of magnitude as well as increased lithium and OIPC cation and anion dynamics were observed in the composite as prepared with 40 v% of polymer nanoparticles with respect to the pure OIPC at 50 °C. This was attributed to the increased overall structural disorder as a result of the formation of disordered interfacial regions, which were evidenced by solid-state NMR spectroscopy. In addition, the importance of the thermal history of these composites is highlighted, with differences in the conductivity and ion dynamics observed after melting and recrystallizing the OIPC component, leading to less disordered interfacial regions. This study enriches our fundamental understanding of the formation of interfacial regions in OIPC composites and their effect on the bulk properties of the electrolyte., (© 2024 Wiley-VCH GmbH.)

Experimental evidence showed that an increase in intracellular chloride concentration [Formula: see text] caused by gamma-aminobutyric acid (GABA) input can promote epileptic firing activity, but the actual mechanisms remain elusive. Here in this theoretical work, we show that influx of chloride and concomitant bicarbonate ion [Formula: see text] efflux upon GABA receptor activation can induce epileptic firing activity by transition of GABA from inhibition to excitation. We analyzed the intrinsic property of neuron firing states as a function of [Formula: see text] We found that as [Formula: see text] increases, the system exhibits a saddle-node bifurcation, above which the neuron exhibits a spectrum of intensive firing, periodic bursting interrupted by depolarization block (DB) state, and eventually a stable DB through a Hopf bifurcation. We demonstrate that only GABA stimuli together with [Formula: see text] efflux can switch GABA's effect to excitation which leads to a series of seizure-like events (SLEs). Exposure to a low [Formula: see text] can drive neurons with high concentrations of [Formula: see text] downward to lower levels of [Formula: see text], during which it could also trigger SLEs depending on the exchange rate with the bath. Our analysis and simulation results show how the competition between GABA stimuli-induced accumulation of [Formula: see text] and [Formula: see text] application-induced decrease of [Formula: see text] regulates the neuron firing activity, which helps to understand the fundamental ionic dynamics of SLE., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 Liu et al.)

Self-diffusion of ions in the protic ionic liquid ethylammonium nitrate (EAN) was studied by 1H NMR pulsed field gradient techniques between 294 and 393 K in the presence of a PTFE insert in a 5-mm NMR tube. At all temperatures, the bulk diffusion of ions (measured by 1H and 15N NMR) can be described by a unique diffusion coefficient. The presence of solid hydrophobic surfaces of PTFE induces regions of EAN in their vicinity, where diffusion of ions, both cations and anions, is reduced compared to the bulk values. An additional line-shape analysis in 1H NMR spectra showed that local mobility of ethylammonium cations in the surface layers near PTFE is also reduced. • 1H and 15N NMR was used to study diffusivity of ethylammonium nitrate enclosed between PTFE surfaces. • The presence of solid hydrophobic surfaces of PTFE induces regions of EAN where diffusion of cations and anions, is reduced. • Line-shape analysis in 1H NMR spectra showed that local mobility of EA cations in the surface layers near PTFE is reduced. [ABSTRACT FROM AUTHOR]

Using ab initio molecular dynamics (AIMD) simulations, classical molecular dynamics (CMD) simulations, small‐angle X‐ray scattering (SAXS), and pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR), the solvation structure and ion dynamics of magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) aqueous electrolyte at 1, 2, and 3 m concentrations are investigated. From AIMD and CMD simulations, the first solvation shell of an Mg2+ ion is found to be composed of six water molecules in an octahedral configuration and the solvation shell is rather rigid. The TFSI− ions prefer to stay in the second solvation shell and beyond. Meanwhile, the comparable diffusion coefficients of positive and negative ions in Mg(TFSI)2 aqueous electrolytes have been observed, which is mainly due to the formation of the stable [Mg(H2O)6]2+ complex, and, as a result, the increased effective Mg ion size. Finally, the calculated correlated transference numbers are lower than the uncorrelated ones even at the low concentration of 2 and 3 m, suggesting the enhanced correlations between ions in the multivalent electrolytes. This work provides a molecular‐level understanding of how the solvation structure and multivalency of the ion affect the dynamics and transport properties of the multivalent electrolyte, providing insight for rational designs of electrolytes for improved ion transport properties. [ABSTRACT FROM AUTHOR]

Mingzhi Dai,1 Zhendong Wu,1 Shaocheng Qi,1 Changhe Huo,1 Qiang Zhang,1 Xingye Zhang,1 Thomas J Webster,2 Hengbo Zhang1 1Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People’s Republic of China; 2Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USACorrespondence: Mingzhi Dai Email daimz@nimte.ac.cnBackground: Electronic devices which mimic the functionality of biological synapses are a large step to replicate the human brain for neuromorphic computing and for numerous medical research investigations. One of the representative synaptic behaviors is paired-pulse facilitation (PPF). It has been widely investigated because it is regarded to be related to biological memory. However, plasticity behavior is only part of the human brain memory behavior.Methods: Here, we present a phenomenon which is opposite to PPF, i.e., paired-pulse inhibition (PPI), in nano oxide devices for the first time. The research here suggests that rather than being enhanced, the phenomena of memory loss would also be possessed by such electronic devices. The device physics mechanism behind memory loss behavior was investigated. This mechanism is sustained by historical memory and degradation manufactured by device trauma to regulate characteristically stimulated origins of artificial transmission behaviors.Results: Under the trauma of a memory device, both the signal amplitude and signal time stimulated by a pulse are lower than the first signal stimulated by a previous pulse in the PPF, representing a new scenario in the struggle for memory. In this way, more typical human brain behaviors could be simulated, including the effect of age on latency and error generation, cerebellar infarct, trauma and memory loss pharmacological actions (such as those caused by hyoscines and nitrazepam).Conclusion: Thus, this study developed a new approach for implementing the manner in which the brain works in semiconductor devices for improving medical research.Keywords: artificial bio synapses, ion dynamics, PPI, paired-pulse pulse inhibition, memory loss

This work reports the effect of sodium aluminate (NaAlO2) filler particles on the ion dynamics of a solid polymer electrolyte system comprising polyethylene oxide, sodium perchlorate (NaClO4) and propylene carbonate. Free-standing flexible polymer electrolyte films were obtained by solution-casting technique. The effect of NaAlO2 fillers in the Na+ transport in the electrolyte system has been investigated using various physical and electrochemical studies. Scanning electron microscopy and X-ray diffraction studies reveal the enhanced amorphicity of the polymer electrolyte system upon dispersion of NaAlO2 fillers. The undispersed polymer electrolyte displays a maximum ionic conductivity of 1.6 × 10−5 S cm−1 at 25°C, which increases to 7.4 × 10−5 S cm−1 on dispersion of 5 wt.% NaAlO2 fillers at 30°C. The ion mobility and enhanced free ion numbers in the dispersed polymer electrolyte system are well-observed in the frequency-dependent dielectric studies. The optimized composition shows a significantly improved Na+ transport number of ~ 0.60 and electrochemical stability window of ~ 4.5 V. [ABSTRACT FROM AUTHOR]

Diverse touch experiences offer a path toward greater human–machine interaction, which is essential for the development of haptic technology. Recent advances in triboelectricity‐based touch sensors provide great advantages in terms of cost, simplicity of design, and use of a broader range of materials. Since performance solely relies on the level of contact electrification between materials, triboelectricity‐based touch sensors cannot effectively be used to measure the extent of deformation of materials under a given mechanical force. Here, an ion‐doped gelatin hydrogel (IGH)‐based touch sensor is reported to identify not only contact with an object but also deformation under a certain level of force. Switchable ionic polarization of the gelatin hydrogel is found to be instrumental in allowing for different sensing mechanisms when it is contacted and deformed. The results show that ionic polarization relies on conductivity of the hydrogels. Quantitative studies using voltage sweeps demonstrate that higher ion mobility and shorter Debye length serve to improve the performance of the mechanical stimuli‐perceptible sensor. It is successfully demonstrated that this sensor offers dynamic deformation‐responsive signals that can be used to control the motion of a miniature car. This study broadens the potential applications for ionic hydrogel‐based sensors in a human–machine communication system. [ABSTRACT FROM AUTHOR]

Solid‐state electrolytes (SSEs) can leapfrog the development of all‐solid‐state batteries (ASSBs), enabling them to power electric vehicles and to store renewable energy from intermittent sources. Here, a new hybrid Li+ and Na+ conducting SSE based on the MIL‐121 metal‐organic framework (MOF) structure is reported. Following synthesis and activation of the MOF, the free carboxylic units along the 1D pores are functionalized with Li+ or Na+ ions by ion exchange. Ion dynamics are investigated by broadband impedance spectroscopy and by 7Li and 23Na NMR spin‐lattice relaxation. A crossover at 50 °C (Li+) and at 10 °C (Na+) from correlated to almost uncorrelated motion at higher temperature is observed, which is in line with Ngai's coupling model. Alternatively, in accordance to the jump relaxation model of Funke, at low temperature only a fraction of the jump processes are successful as lattice rearrangement in the direct vicinity of Li+ (Na+) is slow. 1H NMR unambiguously shows that Li+ is the main charge carrier. Conductivities reach 0.1 mS cm−1 (298 K, Na+) while the activation energies are 0.28 eV (Li+) and 0.36 eV (Na+). The findings pave the way towards development of easily tunable and rationally adjustable high‐performance MOF‐based hybrid SSEs for ASSBs. [ABSTRACT FROM AUTHOR]

Dai M, Wu Z, Qi S, et al. Int J Nanomedicine. 2020;15:1863–1870. The Authors, Editor and Publisher of International Journal of Nanomedicine have agreed to retract the published article. Concerns were raised by the Editor following the authors request to make several corrections to the published article. Many of the requested corrections related to data descriptions in the Materials and Methods and the Results and Discussion. Readers should note the Editor confirms the retraction is not due to academic misconduct but owing to the number of corrections reported within the article which were too numerous to be corrected in a standard corrigendum. The authors may consider republishing a corrected version of the article. The authors agreed with the decision to retract the article to maintain the preciseness of the publication record and wish to apologise for the number of corrections that were reported. Our decision-making was informed by our policy on publishing ethics and integrity and the COPE guidelines on retraction. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”. This retraction relates to this paper

Modeling and simulation of neuronal processes has evolved from the one-dimensional (1D), symmetry-exploiting cable equation to detailed 3D models that incorporate the ultrastructural architecture of neurons. While dimension-reduced models have the clear advantage of simplicity, which makes numerical simulation an easy task, they neglect structural details which may be relevant when studying the structure-function interplay in cells. The Poisson--Nernst--Planck equations represent the other end of the modeling spectrum, a continuum mechanics model that accounts for the 3D domain as well as the spatio-temporal ion concentrations involved in biochemical signaling. In the presented work, we show that three simpler models can be derived from the Poisson--Nernst--Planck equations: the broadly used 1D cable equation, a 3D version thereof, and a 1D electro-diffusion model. We identify the assumptions and approximations that are made for the simpler models and, using numerical simulation, assess the impact of violations of these assumptions on model accuracy in scenarios ranging from individual axon fibers and bundles to dendritic spine microdomains. It is shown that the coarsest model (1D cable equation) is able to accurately resolve the electric behavior in all scenarios, as long as the cellular geometry does not diverge significantly from symmetric local cylinders. In cases where the ionic spatio-temporal dynamics are relevant, more detailed models like the 3D Poisson--Nernst--Planck equations need to be employed. We conclude with guidelines as to which level of modeling detail is necessary to capture the underlying neurobiological features accurately. [ABSTRACT FROM AUTHOR]

This paper reports ZnFe2O4 nanoparticles as a promising dispersoid for a polymer electrolyte system with superior electrochemical properties. The effect of ZnFe2O4 nanoparticles on the physiochemical, electrochemical, and ion dynamic properties of a polymer electrolyte system comprising polyethylene oxide (PEO), sodium triflate (NaCF3SO3), and propylene carbonate (PC) has been studied. ZnFe2O4 prepared by citrate combustion method shows a particle size below 50 nm. The molecular interactions and surface morphology of the electrolyte films have been investigated using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Significant reduction in the crystallinity of the polymer electrolyte system is observed on dispersion of ZnFe2O4 nanoparticles. The electrolyte film with 0.5 wt.% of ZnFe2O4 displays the highest ionic conductivity of 6 × 10−5 S cm−1 at room temperature and electrochemical stability of 4.0 V with superior Na+ transference number of 0.36. The ZnFe2O4 nanoparticles dissociate ions and promote translational motion of the ions within the electrolyte system. [ABSTRACT FROM AUTHOR]

Spontaneous neuronal and astrocytic activity in the neonate forebrain is believed to drive the maturation of individual cells and their integration into complex brain-region-specific networks. The previously reported forms include bursts of electrical activity and oscillations in intracellular Ca2+ concentration. Here, we use ratiometric Na+ imaging to demonstrate spontaneous fluctuations in the intracellular Na+ concentration of CA1 pyramidal neurons and astrocytes in tissue slices obtained from the hippocampus of mice at postnatal days 2-4 (P2-4). These occur at very low frequency (∼2/h), can last minutes with amplitudes up to several millimolar, and mostly disappear after the first postnatal week. To further investigate their mechanisms, we model a network consisting of pyramidal neurons and interneurons. Experimentally observed Na+ fluctuations are mimicked when GABAergic inhibition in the simulated network is made depolarizing. Both our experiments and computational model show that blocking voltage-gated Na+ channels or GABAergic signaling significantly diminish the neuronal Na+ fluctuations. On the other hand, blocking a variety of other ion channels, receptors, or transporters including glutamatergic pathways does not have significant effects. Our model also shows that the amplitude and duration of Na+ fluctuations decrease as we increase the strength of glial K+ uptake. Furthermore, neurons with smaller somatic volumes exhibit fluctuations with higher frequency and amplitude. As opposed to this, larger extracellular to intracellular volume ratio observed in neonatal brain exerts a dampening effect. Finally, our model predicts that these periods of spontaneous Na+ influx leave neonatal neuronal networks more vulnerable to seizure-like states when compared with mature brain. NEW & NOTEWORTHY Spontaneous activity in the neonate forebrain plays a key role in cell maturation and brain development. We report spontaneous, ultraslow, asynchronous fluctuations in the intracellular Na+ concentration of neurons and astrocytes. We show that this activity is not correlated with the previously reported synchronous neuronal population bursting or Ca2+ oscillations, both of which occur at much faster timescales. Furthermore, extracellular K+ concentration remains nearly constant. The spontaneous Na+ fluctuations disappear after the first postnatal week. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) in soil–plant system can abridge plant growth by initiating alterations in root zones. Hydroponics and rhizoboxes are useful techniques to monitor plant responses against various natural and/or induced metal stresses. However, soil based studies are considered more appropriate in order to devise efficient food safety and remediation strategies. The present research evaluated the Cd-mediated variations in elemental dynamics of rhizospheric soil together with in planta ionomics and morpho-physio-biochemical traits of two differentially Cd responsive maize cultivars. Cd-sensitive (31P41) and Cd-tolerant (3062) cultivars were grown in pots filled with 0, 20, 40, 60 and 80 µg/kg CdCl2 supplemented soil. The results depicted that the maize cultivars significantly influenced the elemental dynamics of rhizosphere as well as in planta mineral accumulation under applied Cd stress. The uptake and translocation of N, P, K, Ca, Mg, Zn and Fe from rhizosphere and root cell sap was significantly higher in Cd stressed cv. 3062 as compared to cv. 31P41. In sensitive cultivar (31P41), Cd toxicity resulted in significantly prominent reduction of biomass, leaf area, chlorophyll, carotenoids, protein contents as well as catalase activity in comparison to tolerant one (3062). Analysis of tolerance indexes (TIs) validated that cv. 3062 exhibited advantageous growth and efficient Cd tolerance due to elevated proline, phenolics and activity of antioxidative machinery as compared to cv. 31P41. The cv. 3062 exhibited 54% and 37% less Cd bio-concentration (BCF) and translocation factors (TF), respectively in comparison to cv. 31P41 under highest Cd stress regime. Lower BCF and TF designated a higher Cd stabilization by tolerant cultivar (3062) in rhizospheric zone and its potential use in future remediation plans. [ABSTRACT FROM AUTHOR]

Some ionic liquids (ILs) change their dynamic properties when placed in a confinement between polar surfaces (Filippov et al., Phys. Chem. Chem. Phys. 2018, 20, 6316). The diffusivities of ions and NMR relaxation times in these ILs also reversibly change under a strong static magnetic field. The mechanisms of these phenomena are not clear, but it has been suggested that they involve modified hydrogen-bonding networks formed in these ILs in the presence of polar surfaces. To obtain a better understanding of these effects, we performed temperature-dependent measurements of chemical shifts and diffusion coefficients for ethylammonium nitrate (EAN) IL in the bulk phase (I B) and confined in layers with a thickness of ~4 μm between quartz plates unexposed (I phase) and exposed (I MF phase) to a static magnetic field of 9.4 T. It was shown that the NMR chemical shift of NH 3 protons of EAN in the I phase is strongly shifted upfield, ~0.0145 ppm/K, which is due to weakening of the hydrogen-bonding network of the confined EAN. Exposure to the magnetic field leads to restitution of the hydrogen-bonding (H-bonding network). The temperature dependences of diffusion coefficients follow the order D(I) > D(I B) > D(I MF) and can be described by a Vogel-Fulcher-Tammann approach with variation of the pre-exponential factor, which is determined by the strength of the H-bonding network. Confinement of EAN between plates (I B → I) is an endothermic process, while processes occurring in a magnetic field, I → I MF and I MF → I , are exothermic and endothermic, respectively. Unlabelled Image [ABSTRACT FROM AUTHOR]

Metal halide perovskite single crystals are being explored as functional materials for a variety of optoelectronic applications. Among others, solar cells, field‐effect transistors, and X‐ and γ‐ray detectors have shown improved performance and stability. However, a general uncertainty exists about the relevant mechanisms governing the electronic operation. This is caused by the presence of mobile ions and how these defect species alter the internal electrical field, interact with the contact materials, or modulate electronic properties. Here, a set of high‐quality thick methylammonium lead tribromide single crystals contacted with low‐reactivity chromium electrodes are analyzed by impedance spectroscopy. Through examination of the sample resistance evolution with bias and releasing time, it is revealed that an interplay exists between the perovskite electronic conductivity and the defect distribution within the crystal bulk. Ion diffusion after bias removing changes the local doping density then governing the electronic transport. These findings indicate that the coupling between ionic and electronic properties relies upon a dynamic doping effect caused by moving ions that act as mobile dopants. In addition to electronic features, the analysis extracts values for the ion diffusivity in the range of 10−8 cm2 s−1 in good agreement with other independent measurements. [ABSTRACT FROM AUTHOR]

Sodium bismuth titanate samples with different morphology were synthesized via varying the sintering temperature from 1000 to 1150 °C. The conductivity was significantly affected with the morphology of the system. The dynamics of ions was understood from the conductivity spectra. The dc conductivity, hopping frequency and exponent values were extracted from the conductivity spectra analysis. The impedance and modulus spectroscopy along with exponent behaviour suggested short range hopping for the sample sintered at 1000 °C and followed Ghosh scaling instead of Summerfield scaling. While long-range hopping was observed for the samples sintered at 1150 °C and it followed both the Summerfield scaling and Ghosh scaling. Moreover, the stability of the sample is checked in reducing atmosphere. Image 1 • Dynamics of ions is studied with the sintering temperature in Na 0.5 Bi 0.5 TiO 3-δ. • The conduction mechanism has altered with the sintering temperature. • A correlation between hopping and lattice parameters is also established for NBT. • Stability of the sample is checked in reducing atmosphere. [ABSTRACT FROM AUTHOR]

Understanding the physical origins of the electrical response of cement-based materials is crucial to enhance the capabilities of non-destructive techniques, especially those based on resistivity or electrochemical measurements deployed in durability assessment and monitoring study of concrete structures. In this article, we show that using the information on the composition-dependent dynamics of ions obtained from molecular dynamics simulations improves the estimates of the electrical conductivity of the pore solutions. The link between ion dynamics and electrical conductivity in aqueous solutions is discussed from the fundamentals of ionic transport at the molecular scale. Also, we quantify the variability of pore solution conductivity. For validation, modeling results are extensively compared to experimental measurements on various cement systems. We show that a dilution effect explains the w/c-dependency of the electrical conductivity of the pore solutions. Also, accounting for the age-dependency of ionic diffusion in the pore solution is crucial to capture the age-dependency of the electrical conductivity of the pore solutions. These results are significant because they allow the prediction of the conductivity for various compositions of interest that may be encountered in cement systems. [ABSTRACT FROM AUTHOR]

Being based on mixed ionic‐electronic semiconductors, the operation of perovskite solar cells depends on many parameters. To develop an experimentally validated numerical device model, it is therefore necessary to isolate individual physical phenomena. To this end, the dynamics of ion motion in lead halide perovskites is investigated by measuring impedance spectra and the electric displacement as a function of frequency in dark. The displacement response is fully reproduced by a numerical device model that combines electronic and ionic conduction. For a quantitative description of the displacement, it is critical to consider the frequency‐dependent apparent dielectric constant, the ion concentration and the ion diffusion coefficient. The numerical simulations enable to quantify the effect of ion motion and voltage scan speed on the electric field distribution in MAPbI3 based devices, laying the foundations for an experimentally validated perovskite device model. [ABSTRACT FROM AUTHOR]

Water‐in‐salt electrolytes blended with organics solvents, that is, organic solvent/water mixed electrolytes, are promising for applications in next‐generation energy storage devices vitally needed for industrial electrification and decarbonization. However, the electrolyte ion diffusion behaviors within nanoporous supercapacitor electrodes are poorly understood. Here a systematic investigation into supercapacitor resistances and ion kinetics is carried out experimentally and with numerical simulations. The electrochemical results on the nanoporous electrodes reveal a nonmonotonic (decreasing, increasing, and then decreasing) trend of supercapacitor resistances with increasing solvent mobility, challenging the long‐held views that supercapacitor resistances decrease with elevated mobility of organic solvent. The abnormal trend is examined by numerical molecular dynamics simulations of electrolyte ion diffusion within 0.95 nm nanochannels. The electrolyte conductivity is related to cation–anion interactions within nanochannels. We further confirm the crucial interplay of the van der Waals sizes of solvent molecules and channel width in determining electrolyte conductivity in nanoporous electrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The new Li-ion transport of Li-argyrodite SSEs is summarized in detail. • The description of the lithium substructure of Li argyrodite SSEs provides profound insights. • Methods to improve the ionic conductivity of Li-argyrodite SSEs are well presented. • The ion dynamics of doped Li-argyrodite SSEs is described. • A comprehensive summary was provided on how doping strategies can improve the air stability and electrode compatibility of Li argyrodite SSEs. Sulfide solid-state electrolytes (SSEs), as the most important component of all-solid-state batteries (ASSBs), have a profound impact on their performance. Among the many sulfide SSEs, Li-argyrodite SSEs have been extensively studied and are considered to be one of the most promising solid sulfide-based Li superionic conductors nowadays. However, the SSEs still have some drawbacks to be addressed, such as limited ionic conductivity at room temperature, incompatible electrode/electrolyte interface, low operating voltage window, and poor air stability. It is found that doping strategies have a non-negligible role in solving the above problems. In this review, we first introduce the crystal structures of Li-argyrodite SSEs and provide a detailed description of Li-ion transport in Li-argyrodite SSEs, followed by a detailed description of structure of the Li-sublattice. Next, the mechanism of doping strategies to enhance the ionic conductivity of Li-argyrodite SSEs is focused. Particular emphasis is provided on the ionic dynamics in doped Li-argyrodite SSEs. In addition, the effects of doping strategies (e.g., soft acid ions and metal oxides) on improving the performance (electrode/electrolyte interface and air stability) of Li-argyrodite SSEs are comprehensively presented. Finally, attractive research directions and perspectives for doped Li-argyrodite SSEs are presented, which are of great significance in guiding the energy conversion and storage of Li-argyrodite-based ASSBs. [ABSTRACT FROM AUTHOR]

Climate change and energy crises require the development of new sustainable materials to realise reliable electrochemical energy storage devices. Spinel-type Li _4 Ti _5 O _12 (LTO) is one of the most promising anode materials not only for Li-based batteries, but also for those relying on sodium. While Li ^+ ion dynamics at the early stages of lithiation has been studied already previously, almost no data on the diffusion properties of Na ^+ ions can be found in the literature. Here, we used nucleus-specific ^7 Li and ^23 Na nuclear magnetic resonance (NMR) spectroscopy to quantify the motional processes in mixed-conducting Li _4 Na _x Ti _5 O _12 with x = 0.1, 0.5 and 1.5 on the angstrom length scale. Most importantly, our results reveal a strong increase in Li ^+ diffusivity in the early stages of chemical sodiation that is accompanied by a sharp decrease in activation energy when x reaches 0.5. The two-component ^7 Li NMR spectra point to the evolution of an interfacial solid solution at very low sodiation levels ( x = 0.1). At x = 0.5, these regions emerge over almost the entire crystallite area, enabling rapid 8 a -16 c -8 a Li ^+ exchange (0.4 eV), which leads to facile long-range ion transport. We direct the attention of the reader towards the initial formation of solid solutions in LTO-based anode materials and their capital impact on overall ion dynamics. In contrast to macroscopic electrochemical testing, NMR is uniquely positioned to detect and to resolve these exceptionally fast ion dynamics during the initial stages of sodiation. As these processes crucially determine the fast-charging performance of LTO-type batteries, our study lays the atomistic foundations to establish a general understanding of why two-phase materials such as LTO can act as an impressive insertion host for both Li and Na ions.