Showing papers on "Ion published in 2020"
TL;DR: It is demonstrated that electron transfer plays the dominant role during CE between liquids and solids, which directly impacts the traditional understanding of the formation of an electric double layer at a liquid-solid interface in physical chemistry.
Abstract: As a well-known phenomenon, contact electrification (CE) has been studied for decades. Although recent studies have proven that CE between two solids is primarily due to electron transfer, the mechanism for CE between liquid and solid remains controversial. The CE process between different liquids and polytetrafluoroethylene (PTFE) film is systematically studied to clarify the electrification mechanism of the solid-liquid interface. The CE between deionized water and PTFE can produce a surface charges density in the scale of 1 nC cm-2 , which is ten times higher than the calculation based on the pure ion-transfer model. Hence, electron transfer is likely the dominating effect for this liquid-solid electrification process. Meanwhile, as ion concentration increases, the ion adsorption on the PTFE hinders electron transfer and results in the suppression of the transferred charge amount. Furthermore, there is an obvious charge transfer between oil and PTFE, which further confirms the presence of electron transfer between liquid and solid, simply because there are no ions in oil droplets. It is demonstrated that electron transfer plays the dominant role during CE between liquids and solids, which directly impacts the traditional understanding of the formation of an electric double layer (EDL) at a liquid-solid interface in physical chemistry.
276 citations
TL;DR: The authors demonstrate that the electron transfer paly an important role in liquid-solid contact electrification and the formation mechanism of electric double-layer is proposed.
Abstract: Contact electrification (CE) has been known for more than 2600 years but the nature of charge carriers and their transfer mechanisms still remain poorly understood, especially for the cases of liquid–solid CE. Here, we study the CE between liquids and solids and investigate the decay of CE charges on the solid surfaces after liquid–solid CE at different thermal conditions. The contribution of electron transfer is distinguished from that of ion transfer on the charged surfaces by using the theory of electron thermionic emission. Our study shows that there are both electron transfer and ion transfer in the liquid–solid CE. We reveal that solutes in the solution, pH value of the solution and the hydrophilicity of the solid affect the ratio of electron transfers to ion transfers. Further, we propose a two-step model of electron or/and ion transfer and demonstrate the formation of electric double-layer in liquid–solid CE. The identity of charge carriers (electron or ion) in contact electrification has been discussed for many years. Here, the authors demonstrate that the electron transfer paly an important role in liquid-solid contact electrification and the formation mechanism of electric double-layer is proposed.
268 citations
TL;DR: This review comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
Abstract: Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
236 citations
TL;DR: Theoretical simulations indicate that ion–carboxyl interactions substantially reduce the energy barrier for monovalent cations to pass through the MOFSNC, and thus lead to ultrahigh ion selectivity, and suggest ways to develop ion selective devices for efficient ion separation, energy reservation and power generation.
Abstract: Biological ion channels have remarkable ion selectivity, permeability and rectification properties, but it is challenging to develop artificial analogues. Here, we report a metal–organic framework-based subnanochannel (MOFSNC) with heterogeneous structure and surface chemistry to achieve these properties. The asymmetrically structured MOFSNC can rapidly conduct K+, Na+ and Li+ in the subnanometre-to-nanometre channel direction, with conductivities up to three orders of magnitude higher than those of Ca2+ and Mg2+, equivalent to a mono/divalent ion selectivity of 103. Moreover, by varying the pH from 3 to 8 the ion selectivity can be tuned further by a factor of 102 to 104. Theoretical simulations indicate that ion–carboxyl interactions substantially reduce the energy barrier for monovalent cations to pass through the MOFSNC, and thus lead to ultrahigh ion selectivity. These findings suggest ways to develop ion selective devices for efficient ion separation, energy reservation and power generation. Here, using an interfacial growth strategy, UiO-66 MOF nanocrystals are asymmetrically embedded into conical pores in a polymer membrane. These pores have a mono/divalent cation selectivity of 103, which can be tuned by pH, and act as ionic rectifiers.
228 citations
224 citations
TL;DR: In this article, the authors provide a well-timed and critical appraisal of recent advances in the engineering of TMDs at the atomic level for AMIBs, by combining computational and experimental approaches.
Abstract: In the past few decades, great effort has been made toward the preparation and development of advanced transition metal dichalcogenide (TMD) materials for anodes of alkali metal ion batteries (AMIBs). However, their electrochemical performance is still severely impaired by structural aggregation and fracture during the conversion reaction. To address these issues, various methodologies for the fabrication of hierarchical and hybrid nanostructures, with optimization of materials and electrodes, have been fully investigated and reviewed. As regards tuning the TMD-based materials, extensive efforts have been undertaken toward optimization of their intrinsic structure at the atomic level, including surface defects, interlayer spacing expansion, phase control, alloying, and heteroatom doping. However, the design strategies and methods to manipulate the intrinsic structures and electrochemical mechanisms in AMIBs have not been fully summarized. This review provides a well-timed and critical appraisal of recent advances in the engineering of TMDs at the atomic level for AMIBs, by combining computational and experimental approaches. The correlation between these strategies and electrochemical performance is highlighted. The challenges and opportunities in this research field are also outlined. We expect that this review would be beneficial for improving the overall knowledge on the charge storage mechanisms in TMDs and for pointing out the importance of intrinsic structure engineering for enhancing the performance of TMDs in energy storage.
218 citations
TL;DR: In this article, an overview on the recent advances in the fundamental understanding of how these interfaces influence the performance of hybrid perovskite solar cells (HPSCs) is provided.
Abstract: Organic-inorganic hybrid perovskite solar cells (HPSCs) have achieved an impressive power conversion efficiency (PCE) of 25.2% in 2019. At this stage, it is of paramount importance to understand in detail the working mechanism of these devices and which physical and chemical processes govern not only their power conversion efficiency but also their long-term stability. The interfaces between the perovskite film and the charge transport layers are among the most important factors in determining both the PCE and stability of HPSCs. Herein, an overview is provided on the recent advances in the fundamental understanding of how these interfaces influence the performance of HPSCs. Firstly, it is discussed how the surface energy of the charge transport layer, the energy level alignment at the interfaces, the charge transport in interfacial layers, defects and mobile ions in the perovskite film, and interfacial layers or at the interfaces affect the charge recombination as well as hysteresis and light soaking phenomenon. Then it is discussed how the interfaces and interfacial materials influence the stability of HPSCs. At the same time, an overview is also provided on the various design strategies for the interfaces and the interfacial materials. At the end, the outlook for the development of highly efficient and stable HPSCs is provided.
201 citations
TL;DR: In this article, the authors demonstrate the preparation of integrated tubular metal-organic framework architectures using a 3D scaffold, and their derivative of nitrogen-doped carbon tubes (denoted as NCTs) that possess a maximum salt adsorption capacity of 56.9 µg−1 and good cycling stability.
181 citations
TL;DR: Values of ion dissociation for ILs and IL solutions (aqueous and nonaqueous) determined by both the traditional molar conductivity/PFG-NMR method and the ρ, η, λ method are presented.
Abstract: The extent to which cations and anions in ionic liquids (ILs) and ionic liquid solutions are dissociated is of both fundamental scientific interest and practical importance because ion dissociation has been shown to impact viscosity, density, surface tension, volatility, solubility, chemical reactivity, and many other important chemical and physical properties. When mixed with solvents, ionic liquids provide the unique opportunity to investigate ion dissociation from infinite dilution in the solvent to a completely solvent-free state, even at ambient conditions. The most common way to estimate ion dissociation in ILs and IL solutions is by comparing the molar conductivity determined from ionic conductivity measurements such as electrochemical impedance spectroscopy (EIS) (which measure the movement of only the charged, i.e., dissociated, ions) with the molar conductivity calculated from ion diffusivities measured by pulse field gradient nuclear magnetic resonance spectroscopy (PFG-NMR, which gives movement of all of the ions). Because the NMR measurements are time-consuming, the number of ILs and IL solutions investigated by this method is relatively limited. We have shown that use of the Stokes-Einstein equation with estimates of the effective ion Stokes radii allows ion dissociation to be calculated from easily measured density, viscosity, and ionic conductivity data (ρ, η, λ), which is readily available in the literature for a much larger number of pure ILs and IL solutions. Therefore, in this review, we present values of ion dissociation for ILs and IL solutions (aqueous and nonaqueous) determined by both the traditional molar conductivity/PFG-NMR method and the ρ, η, λ method. We explore the effect of cation and anion alkyl chain length, structure, and interaction motifs of the cation and anion, temperature, and the strength of the solvent in IL solutions.
161 citations
TL;DR: This work demonstrates a zinc hybrid-ion battery (ZHIB) with an unusual capacity enhancement even within 18000 cycles by employing V2CTX MXene as the cathode, enormously differing from all the reported counterparts with capacity degradation initiated within hundreds of cycles.
Abstract: Nonbattery behavior related phase transition of electrodes is usually not favorable for any batteries because it results in performance degradation at all times. Here, we demonstrate a zinc hybrid-...
149 citations
TL;DR: In this paper, the effects of heavy ion induced modification on the structural, morphological and optical properties of potassium sodium niobate (KNN) thin films have been investigated using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy, and UV-Vis spectroscope.
Abstract: In the present study, the effects of swift heavy ion induced modification on the structural, morphological and optical properties of potassium sodium niobate (KNN) thin films have been investigated. KNN thin films were deposited using RF magnetron sputtering onto Si and quartz substrates. Subsequently, as-deposited films were annealed at 700 °C in air ambience for crystallization. Eventually, these crystalline films were irradiated using 100 MeV Ag ions at various fluences ranging from 1 × 1012 to 1 × 1013 ions/cm2. The crystalline and irradiated films were characterized using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy, and UV–Vis spectroscopy. XRD results reveal that the crystallinity of films decreases drastically upon irradiation and almost disappeared at 1 × 1013 ions/cm2. Raman spectra show the different vibration modes of NbO6 octahedra. Raman peaks intensity is decreased and the peaks get broadened due to irradiation which indicates the amorphous nature of films. Variation in surface morphology and roughness of films before and after irradiation is studied using AFM. The minimum value of roughness is observed at 5 × 1012 ions/cm2. Ion beam irradiation results in the variation of transmittance and optical band gap of the films. The optical band gap of crystalline KNN film is found to be 3.82 eV which decreased to 3.72 eV upon irradiation at 5 × 1012 ions/cm2. The monotonous decrease in the refractive index and packing density of films is also observed with ion fluence.
TL;DR: This work adopts iron single-atom catalysts (Fe-N-C SACs) as an advanced coreactant accelerator to directly reduce the dissolved oxygen (O2) into reactive oxygen species (ROS) and sheds light on boosting the ECL emission of the luminol-dissolved O2 sensing platform, providing a new pathway for further research of a luminol's ECL system.
Abstract: The traditional luminol-H2 O2 electrochemiluminescence (ECL) sensing platform suffers from self-decomposition of H2 O2 at room temperature, hampering its application for quantitative analysis. In this work, for the first time we employ iron single-atom catalysts (Fe-N-C SACs) as an advanced co-reactant accelerator to directly reduce the dissolved oxygen (O2 ) to reactive oxygen species (ROS). Owing to the unique electronic structure and catalytic activity of Fe-N-C SACs, large amounts of ROS are efficiently produced, which then react with the luminol anion radical and significantly amplify the luminol ECL emission. Under the optimum conditions, a Fe-N-C SACs-luminol ECL sensor for antioxidant capacity measurement was developed with a good linear range from 0.8 μm to 1.0 mm of Trolox.
TL;DR: What anionic redox is and the nature of the transition metal and oxygen bond is defined accompanied by three subsequent sections bridging the redox spectrum from pure anionic, to a mix of cationic and anionic and purecationic.
Abstract: Lithium-ion batteries have proven themselves to be indispensable among modern day society. Demands stemming from consumer electronics and renewable energy systems have pushed researchers to strive for new electrochemical technologies. To this end, the advent of anionic redox, that is, the sequential or simultaneous redox of the cation and anion in a transition metal oxide based cathode for a Li-ion battery, has garnered much attention due to the enhanced specific capacities. Unfortunately, the higher energy densities are plagued with problems associated with the irreversibility of anionic redox. Much effort has been placed on finding a suitable composition of transition metal oxide, with some groups identifying the underlying features and relationship for anion redox and cationic redox to occur reversibly. Accordingly, it is timely to review anionic redox in terms of what anionic redox is with emphasis on the mechanism and the evidence underlying its discovery and validation. To follow will be a section defining the nature of the transition metal and oxygen bond accompanied by three subsequent sections bridging the redox spectrum from pure anionic, to a mix of cationic and anionic and pure cationic.
TL;DR: In this article, a review of metal-organic frameworks (MOFs) and their derivatives as anode materials for high-performance lithium-ion batteries is presented, and strategies are proposed for further enhancing their performance.
TL;DR: In this article, the authors proposed two approaches to compute the band diagram of perovskite solar cells, both based on the migration of a single mobile ion (halide vacancies).
TL;DR: The results reveal that in the solution processed MAPbI3 thin films transport of electrons dominates over holes, and it is shown that the direction of the hysteresis in the current-voltage characteristics provides a fingerprint for the sign of the dominant moving ionic species.
Abstract: Hybrid organic-inorganic perovskites are promising materials for the application in solar cells and light-emitting diodes. However, the basic current-voltage behavior for electrons and holes is still poorly understood in these semiconductors due to their mixed electronic-ionic character. Here, we present the analysis of space-charge-limited electron and hole currents in the archetypical perovskite methyl ammonium lead iodide (MAPbI3). We demonstrate that the frequency dependence of the permittivity plays a crucial role in the analysis of space-charge-limited currents and their dependence on voltage scan rate and temperature. Using a mixed electronic-ionic device model based on experimentally determined parameters, the current-voltage characteristics of single-carrier devices are accurately reproduced. Our results reveal that in our solution processed MAPbI3 thin films transport of electrons dominates over holes. Furthermore, we show that the direction of the hysteresis in the current-voltage characteristics provides a fingerprint for the sign of the dominant moving ionic species. Space-charge-limited currents are widely used to characterize charge transport in semiconductors. Here, the authors characterize space-charge-limited electron and hole currents in metal-halide perovskites, applicable in emerging solar cells. The currents are strongly influenced by the high permittivity and ion motion.
TL;DR: In this paper, an exotic 2D FMS based on rare-earth ions with f-electrons, a GdI2 monolayer, is predicted to have a large magnetization (8 μB f.u.−1), whose ferromagnetism can survive near room temperature (241 K) with a small exfoliation energy from its layered van der Waals (vdW) bulk.
Abstract: Two-dimensional (2D) ferromagnetic semiconductors (FMSs) exhibit novel spin-dependent electronic and optical properties, opening up exciting opportunities for nanoscale spintronic devices. However, experimentally confirmed 2D FMSs based on transition metal ions are rather limited and their performances are not satisfactory, e.g. typically with low Curie temperatures and small magnetic signals. Different from most known 2D magnets based on d-electrons, here an exotic 2D FMS based on rare-earth ions with f-electrons, a GdI2 monolayer, is predicted to have a large magnetization (8 μB f.u.−1), whose ferromagnetism can survive near room temperature (241 K). In addition, with a small exfoliation energy from its layered van der Waals (vdW) bulk, this GdI2 monolayer holds excellent dynamical and thermal stabilities, making our prediction promising in experiments. Our prediction not only offers a compelling FMS for spintronics, but also provides an alternative route to acquire more high-performance 2D FMSs, going beyond pure d-electron compounds.
TL;DR: In this paper, an elaborate graphene oxide (GO) nanosheets/cellulose nanofibers (CNFs) assembled membrane is reported to improve confined ion transport for high-performance osmotic energy conversion.
Abstract: As an emerging potential energy source to address the energy crisis, osmotic energy has attracted increasing attention. Fast ion transport is essential for this blue energy and for other membrane-based energy systems to achieve low membrane resistance and high ion selectivity for power density. However, the current nanochannel membranes suffer from a high energy barrier for ion transmembrane movement because of the narrow channel size and the low charge density, which results in low current and undesirable power density. Here, an elaborate graphene oxide (GO) nanosheets/cellulose nanofibers (CNFs) assembled membrane is reported to improve confined ion transport for high-performance osmotic energy conversion. CNFs, the most abundant natural nanomaterial with highly anisotropic properties and a high density of functional groups, not only enlarge the original narrow channel, which reduces the energy barrier for ion transport, but also introduce space charge between pristine GO nanosheets to maintain ion selectivity. Benefiting from the effective assembly of GO and CNFs, a high power density of 4.19 W m−2 with an improved current is obtained by mixing artificial seawater and river water. Moreover, a power density of 7.20 W m−2, which is higher than the standard for commercialization, is achieved at 323 K. The osmotic energy conversion shows a nonlinear thermal dependence relationship at high temperatures due to bubble nucleation. This material design strategy can provide an alternative concept to effectively enhance ion transport in membrane-based fields such as separations, desalination, flow batteries and fuel cells.
TL;DR: Charge assignment for individual ions unlocks complex mixtures of proteoforms and their assemblies by native mass spectrometry, revealing information not obtainable by typical measurements of ensembles of ions.
Abstract: An Orbitrap-based ion analysis procedure determines the direct charge for numerous individual protein ions to generate true mass spectra. This individual ion mass spectrometry (I2MS) method for charge detection enables the characterization of highly complicated mixtures of proteoforms and their complexes in both denatured and native modes of operation, revealing information not obtainable by typical measurements of ensembles of ions.
01 Jan 2020
TL;DR: Lee et al. as discussed by the authors presented an ORCID identification number for the author(s) of this article under https://doi.org/10.1002/smtd.201900648.
Abstract: Dr. J. W. Chen, Prof. P. S. Lee School of Materials Science and Engineering Nanyang Technological University Singapore 639798, Singapore E-mail: pslee@ntu.edu.sg Dr. J. W. Chen, Prof. P. S. Lee Singapore-HUJ Alliance for Research and Enterprise (SHARE) Nanomaterials for Energy and Energy Water Nexus (NEW) Campus for Research Excellence and Technological Enterprise (CREATE) Singapore 138602, Singapore Prof. D. H. C. Chua Material Sciences and Engineering Department National University of Singapore Singapore 117575, Singapore The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smtd.201900648.
TL;DR: This work offers an ionic engineering strategy to enable fast and durable charge transfer in materials, holding great promise for providing guidance for the material design of related energy storage systems.
Abstract: Boosting charge transfer in materials is critical for applications involving charge carriers. Engineering ionic channels in electrode materials can create a skeleton to manipulate their ion and electron behaviors with favorable parameters to promote their capacity and stability. Here, tailoring of the atomic structure in layered potassium niobate (K4 Nb6 O17 ) nanosheets and facilitating their application in lithium and potassium storage by dehydration-triggered lattice rearrangement is reported. The spectroscopy results reveal that the interatomic distances of the NbO coordination in the engineered K4 Nb6 O17 are slightly elongated with increased degrees of disorder. Specifically, the engineered K4 Nb6 O17 shows enhanced electrical and ionic conductivity, which can be attributed to the enlarged interlamellar spacing and subtle distortions in the fine atomic arrangements. Moreover, subsequent experimental results and calculations demonstrate that the energy barrier for Li+ /K+ diffusion is significantly lower than that in pristine K4 Nb6 O17 . Interestingly, the diffusion coefficient of K+ is one order of magnitude higher than that of Li+ , and the engineered K4 Nb6 O17 presents superior electrochemical performance for K+ to Li+ . This work offers an ionic engineering strategy to enable fast and durable charge transfer in materials, holding great promise for providing guidance for the material design of related energy storage systems.
TL;DR: In this paper, a semi-coherent LiMn1.5Ni0.5O4 spinel-like shell was established in operando with little oxygen loss to integrally wrap the LiCoO2 bulk.
Abstract: The cycling stability of LiCoO2 under high voltages (>4.5 V) was plagued by hybrid anion- and cation-redox (HACR) induced oxygen escape and uncontrolled phase collapse. With DEMS and in situ XANES mapping at the NSLS-II, we demonstrate that oxygen escape triggers irreversible transformations into “bad” surface phases that rapidly propagate inward. Enabling HACR but stopping global oxygen migration is key to a stable high-energy cathode. Therefore, we developed ∼10 μm single crystals with LiCoO2 in the bulk smoothly transitioning to Co-free LiMn0.75Ni0.25O2 at the surface. By means of initial electrochemical formation, a semi-coherent LiMn1.5Ni0.5O4 spinel-like shell was established in operando with little oxygen loss to integrally wrap the LiCoO2 bulk. Then we obtained gradient-morph LiCoO2 single crystals to prevent the percolating migration of oxygen out of the particle and achieved enhanced HACR reversibility at high voltages. The gradient-morph HACR cathode undergoes substantially stabilized cycling when charged to above 4.6 V, and hence a stable cyclic volumetric energy density of >3400 W h L−1 has been achieved in a pouch full-cell coupled with a commercial graphite anode and lean electrolyte (2 g A h−1), exhibiting up to 2906 W h L−1 even after 300 cycles.
TL;DR: This work establishes a clear atomic-level correlation between cation substitution, anion vacancies, and OER performance, but also provides valuable insights for the rational design of highly efficient catalysts for OER.
Abstract: Due to the earth abundance and tunable electronic properties, etc., transition metal oxides (TMOs) show attractive attention in oxygen evolution reaction. O-vacancies (Vo ) play important roles in tailoring the local surface and electronic environment to lower the activation barriers. Herein, an effective strategy is shown to enhance the oxygen evolution reduction (OER) performance on Co3 O4 ultrathin nanosheets via combined cation substitution and anion vacancies. The oxygen-deficient Fe-Co-O nanosheets (3-4 nm thickness) display an overpotential of 260 mV@10 mA cm-2 and a Tafel slope of 53 mV dec-1 , outperforming those of the benchmark RuO2 in 1.0 m KOH. Further calculations demonstrate that the combined introduction of Fe cation and Vo with appropriate location and content finely tune the intermediate absorption, consequently lowering the rate-limiting activation energy from 0.82 to as low as 0.15 eV. The feasibility is also proved by oxygen-deficient Ni-Co-O nanosheets. This work not only establishes a clear atomic-level correlation between cation substitution, anion vacancies, and OER performance, but also provides valuable insights for the rational design of highly efficient catalysts for OER.
TL;DR: In this article, the influence of nitrogen ion implantation on the properties of copper oxide thin films, prepared using DC magnetron sputtering, was investigated by means of X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy, and UV-visible spectrophotometer.
TL;DR: A class of membranes assembled with two-dimensional transition-Metal phosphorus trichalcogenide nanosheets, in which the transition-metal vacancies enable exceptionally high ion conductivity is reported, which is crucial for the application in energy storage and conversion.
Abstract: Proton transport in nanochannels under humid conditions is crucial for the application in energy storage and conversion. However, existing materials, including Nafion, suffer from limited conductivity of up to 0.2 siemens per centimeter. We report a class of membranes assembled with two-dimensional transition-metal phosphorus trichalcogenide nanosheets, in which the transition-metal vacancies enable exceptionally high ion conductivity. A Cd0.85PS3Li0.15H0.15 membrane exhibits a proton conduction dominant conductivity of ~0.95 siemens per centimeter at 90° Celsius and 98% relative humidity. This performance mainly originates from the abundant proton donor centers, easy proton desorption, and excellent hydration of the membranes induced by cadmium vacancies. We also observed superhigh lithium ion conductivity in Cd0.85PS3Li0.3 and Mn0.77PS3Li0.46 membranes.
TL;DR: In this paper, the volume expansion factor of anodic TiO2 nanotubes was found to be 2.073 and the ratio of the total volume of the nanotube array to the volume of consumed titanium was 2.285.
TL;DR: In this paper, a mechanism involving fluorine loss and structure transformation during heat treatment of Na3V2(PO4)2F3/C is proposed to understand this phenomenon.
TL;DR: The uniform Li2SiO3 coating layer not only improves the Li-ion diffusion kinetics of the electrode, but also reduces mechanical micro-strain, stabilizes the surface chemistry and structure with strong Si-O covalent bond, and help to develop high capacity cathode materials for next-generation high energy density Li-ions.
Abstract: Ni-rich cathode materials LiNixCoyMn1–x–yO2 (x ≥ 0.6) have attracted much attention due to their high capacity and low cost. However, they usually suffer from rapid capacity decay and short cycle l...