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Charge compensation on anionic redox reaction (ARR) has been promising to realize extra capacity beyond transition metal redox in battery cathodes. The practical development of ARR capacity has been hindered by high-valence oxygen instability, particularly at cathode surfaces. However, the direct probe of surface oxygen behavior has been challenging. Here, the electronic states of surface oxygen are investigated by combining mapping of resonant Auger electronic spectroscopy (mRAS) and ambient pressure X-ray photoelectron spectroscopy (APXPS) on a model LiCoO

Summary Oxygen activity in highly delithiated LiCoO2 is critical to fully utilizing the energy density of this high-tap-density cathode but still lacks a clear understanding. In this work, we combined the results of several experimental techniques, especially resonant inelastic X-ray scattering (RIXS) and neutron pair distribution function (NPDF) analysis, together with theoretical calculations to study this topic. Our results conclude that oxygen redox takes place globally in the lattice, rather than forming localized dimerization as previously thought. RIXS results directly reveal the reversible oxygen redox, and NPDF results show that the O–O pair distance is considerably shortened in the highly delithiated LiCoO2. Theoretical calculations indicate that no O–O bonding is formed in LiCoO2, in sharp contrast to the lithium-rich system in which O–O bonding does form. These results provide the rationale for achieving a reversible deep delithiation and high energy density for LiCoO2-based electrodes.

All-solid-state batteries have been considered as the ultimate solution for energy storage systems with high energy density and high safety. However, the obvious solid-solid contact and the interface stability issues pose great challenges to the construction of all-solid-state batteries with practically usable performances. Here, we discover that the heat-initiated polymerization of vinylene carbonate (VC) and the simultaneous incorporation of cathode electrolyte interphase (CEI) forming additive lithium difluoro(oxalato)borate (LiDFOB) can synergistically promote the formation of a high-voltage stable and low resistant interface layer between the cathode and solid electrolyte. A poly(ethylene oxide) PEO-based all-solid-state lithium battery (ASSLB) employing the LiCoO2 cathode electrode modified through such an in-situ CEI strategy demonstrates superior 4.2 ​V cycle stability, with a discharge capacity retention of 71.5% after 500 cycles. Besides, the accelerating rate calorimetry (ARC) test reveals that the cell displays extraordinary safety performance with no distinct thermal runaway below 350 ​°C. This work demonstrates an effective interface engineering strategy that can promise the formation of electrochemically and thermally stable cathode/solid electrolyte interface which is essential for the stable and safe operation of ASSLBs. Moreover, the validation of stable cycling of PEO-based ASSLBs at high voltages may encourage the efforts on further optimizations of interface engineering processes as well as large-scale fabrication, as the improvement of the energy-densities of PEO-based ASSLBs will be of paramount significance for practical applications.

Summary Real-world industry-relevant battery composite electrodes are hierarchically structured. In particular for active cathode particles, there is a consensus that their structural and chemical defects could have a profound impact on battery performance. An in-depth understanding of the underlying mechanisms could critically inform cathode material engineering, which remains a daunting challenge at present. Herein, we tackle this question by studying LiCoO2 (LCO) with trace doping of Ti, which exhibits low solubility in the LCO-layered lattice. We observed the spontaneous and heterogeneous segregation of the dopant (Ti), which modified the particle surface and the buried grain boundaries while inducing a significant amount of lattice distortions. These multiscale structural defects promote the robustness of the LCO lattice at a deeply charged state (above 4.5 V). Our result formulates a multiscale defect-engineering strategy that could be applicable to the synthesis of a broad range of energy materials.

Exploring alternative rechargeable batteries with energy densities above state-of-the-art lithium-ion batteries is the critical challenge for both academia and industry. Herein, thermodynamic calculations are performed to obtain: 1) theoretical energy densities (based on the cathode and anode active materials) of 1683 kinds of batteries of conversion reaction chemistry using Li, Na, K, Mg, Al, and Zn as the anodes; and 2) electromotive force (EMF, also known as thermodynamic equilibrium voltage) of these batteries. Among these batteries, theoretical energy density above 1000 ​Wh kg−1, 800 ​Wh L−1 and EMF over 1.50 ​V are taken as the screening criteria to reveal significant battery systems. In addition, hazard and cost issues are examined. Ultimately, there are 51 kinds of batteries satisfying the screening criteria, including O2/Li, O2/Al, O2/Mg, H2O/Li, CO2/Li, S/Li, CO2/Al, H2O/Al batteries. Moreover, practical energy densities of the cells are estimated using a solid-state pouch cell with electrolyte of PEO/LiTFSI. Knowing the batteries with high energy densities will guide the research and development on the next-generation energy storage.

The dissolution of transition-metal (TM) cations into a liquid electrolyte from cathode material, such as Mn ion dissolution from LiMn2O4 (LMO), is detrimental to the cycling performance of Li-ion batteries (LIBs). Though much attention has been paid to this issue, the behavior of Mn dissolution has not been clearly revealed. In this work, by using a refined in situ ultraviolet-visible (UV-vis) spectroscopy technique, we monitored the concentration changes of dissolved Mn ions in liquid electrolyte from LMO at different state of charge (SOC), confirming the maximum dissolution concentration and rate at 4.3 V charged state and Mn2+ as the main species in the electrolyte. Through ab initio molecular dynamics (AIMD) simulations, we revealed that the Mn dissolution process is highly related to surface structure evolution, solvent decomposition, and lithium salt. These results will contribute to understanding TM dissolution mechanisms at working conditions as well as the design of stable cathodes.

LiCoO2 is a dominant cathode material for lithium-ion (Li-ion) batteries due to its high volumetric energy density, which could potentially be further improved by charging to high voltages. However, practical adoption of high-voltage charging is hindered by LiCoO2’s structural instability at the deeply delithiated state and the associated safety concerns. Here, we achieve stable cycling of LiCoO2 at 4.6 V (versus Li/Li+) through trace Ti–Mg–Al co-doping. Using state-of-the-art synchrotron X-ray imaging and spectroscopic techniques, we report the incorporation of Mg and Al into the LiCoO2 lattice, which inhibits the undesired phase transition at voltages above 4.5 V. We also show that, even in trace amounts, Ti segregates significantly at grain boundaries and on the surface, modifying the microstructure of the particles while stabilizing the surface oxygen at high voltages. These dopants contribute through different mechanisms and synergistically promote the cycle stability of LiCoO2 at 4.6 V. LiCoO2 is a widely used cathode material in Li-ion batteries for applications such as portable electronics. Here, the authors report multiple-element doping to enable stable cycling of LiCoO2 at high voltages that are not yet accessible with commercial Li-ion batteries.

Aqueous K-ion batteries (AKIBs) are promising candidates for grid-scale energy storage due to their inherent safety and low cost. However, full AKIBs have not yet been reported due to the limited availability of suitable electrodes and electrolytes. Here we propose an AKIB system consisting of an Fe-substituted Mn-rich Prussian blue KxFeyMn1 − y[Fe(CN)6]w·zH2O cathode, an organic 3,4,9,10-perylenetetracarboxylic diimide anode and a 22 M KCF3SO3 water-in-salt electrolyte. The cathode achieves 70% capacity retention at 100 C and a lifespan of over 10,000 cycles due to the mitigation of phase transitions by Fe substitution. Meanwhile, the electrolyte can help decrease the dissolution of both electrodes owing to the lack of free water. The AKIB exhibits a high energy density of 80 Wh kg−1 and can operate well at rates of 0.1–20 C and over a wide temperature range (−20 to 60 °C). We believe that our demonstration could pave the way for practical applications of AKIBs for grid-scale energy storage. Intensive efforts are underway towards developing battery-based grid-scale storage technologies. Here, the authors report an aqueous K-ion battery that offers many attractive advantages over various battery alternatives.

The dissolution of transition-metal (TM) cations into a liquid electrolyte from cathode material, such as Mn ion dissolution from LiMn

Realizing the charging of LiCoO2 to 4.6 V (vs. Li/Li+) reversibly has important value for achieving high volumetric and gravimetric energy density in rechargeable lithium batteries. However, the surface and interface instability of electrode at high voltage remains a primary problem. In this work, cathode electrolyte interphase (CEI) layer on LiCoO2 has been studied by X-ray photoelectron spectroscopy (XPS). In LiCoO2/Li battery, the dynamic evolution of CEI layer upon charging and discharging has been observed. Based on quantitative XPS analysis, a strong correlation on interface products between cathode and Li anode has been established. Such correlation mainly originates from the reversible formation and dissolution of the SEI layer on Li anode. The CEI layer evolution can be attributed to the sequential reactions through electrolyte and possibly physical migration of SEI fragments from Li anode. While in LiCoO2/graphite battery, the changes of the CEI on LiCoO2 becomes less significant due to the relative stable solid electrolyte interphase (SEI) layer forming on graphite anode, which further supports the strong correlation between CEI on cathode and solid electrolyte interphase (SEI) on Li anode. These results reveal the origin of the dynamical evolution of CEI on LiCoO2, and highlight that the impact of anode should be considered when interpreting the CEI on cathode, especially in rechargeable lithium batteries using lithium as anode.

Cathode electrolyte interphase (CEI) layer plays an essential role in determining the electrochemical performance of Li-ion batteries (LIBs), but the detailed mechanisms of CEI formation and evolution are not yet fully understood. With the pursuit of LIBs possessing a high energy density, fundamental investigations on the CEI have become increasingly important. Herein, X-ray photoelectron spectroscopy (XPS) is employed to fingerprint CEI formation and evolution on three of the most prevailing high-voltage cathodes including layered Li

Surface modification of LiCoO2 with the ultrathin film of solid state electrolyte of Li1.4Al0.4Ti1.6(PO4)3 (LATP) has been realized by a new and facile solution-based method. The coated LiCoO2 reveals enhanced structural and electrochemical stability at high voltage (4.5 V vs Li+/Li) in half-cell with liquid electrolyte. Transmission electron microscopy (TEM) images show that a dense LATP coating layer is covered on the surface of LiCoO2 uniformly with thickness of less than 20 nm. The LATP coating layer is proven to be able to prevent the direct contact between the cathode and the electrolyte effectively and thus to suppress the side reactions of liquid electrolyte with LiCoO2 surface at high charging voltage. As a result, dissolution of Co3+ has been largely suppressed over prolonged cycling as indicated by the X-ray photoelectron spectroscopy (XPS) measurements. Due to this surface passivating feature, the electrochemical performance of 0.5 wt% LATP modified LiCoO2 has also been evaluated in an all solid lithium battery with poly(ethylene oxide)-based polymer electrolyte. The cell exhibits 93% discharge capacity retention of the initial discharge capacity after 50 cycles at the charging cut-off voltage of 4.2 V, suggesting that the LATP coating layer is effective to suppress the oxidation of PEO at high voltage.

Rechargeable sodium-ion batteries with earth-abundant Fe/Mn based cathodes are a promising choice for grid-scale applications. However, the key candidate, P2-type Fe-based materials, suffers from severe voltage decay during battery operation due to Fe3+ migration to the neighboring tetrahedral sites. In this study, two Fe-based layered oxides, Na0.7[Cu0.15Fe0.3Mn0.55]O2 and Na0.7[Cu0.2Fe0.2Mn0.6]O2, were prepared. With a combination of in situ XRD, X-ray PDF, and hard and soft X-ray absorption, we demonstrate that the voltage decay in Fe-based layered oxides has dynamic origins. Drastic phase transition can be triggered by higher upper voltage limit, while partially irreversible Fe migration leads to voltage fading. With excess Cu doped into the crystal lattice, Fe migration can be considerably mitigated and therefore, structural stability can be maintained. Furthermore, Cu introduction brings about extra capacity via the correlation between transition metal elements and ligand oxygen, which may well compensate for capacity loss from inert impurity doping. Possible strategies for suppressing the detrimental voltage decay in battery cathodes can be proposed accordingly.

We report a method for in situ atomic-scale observation of electrochemical delithiation in a working all-solid-state battery using a state-of-the-art chip based in situ transmission electron microscopy (TEM) holder and focused ion beam milling to prepare an all-solid-state lithium-ion battery sample. A battery consisting of LiCoO2 cathode, LLZO solid state electrolyte and gold anode was constructed, delithiated and observed in an aberration corrected scanning transmission electron microscope at atomic scale. We found that the pristine single crystal LiCoO2 became nanosized polycrystal connected by coherent twin boundaries and antiphase domain boundaries after high voltage delithiation. This is different from liquid electrolyte batteries, where a series of phase transitions take place at LiCoO2 cathode during delithiation. Both grain boundaries become more energy favorable along with extraction of lithium ions through theoretical calculation. We also proposed a lithium migration pathway before and after polycrystallization. This new methodology could stimulate atomic scale in situ scanning/TEM studies of battery materials and provide important mechanistic insight for designing better all-solid-state battery.

The use of anion redox reactions is gaining interest for increasing rechargeable capacities in alkaline ion batteries. Although anion redox coupling of S2− and (S2)2− through dimerization of S–S in sulfides have been studied and reported, an anion redox process through electron hole formation has not been investigated to the best of our knowledge. Here, we report an O3-NaCr2/3Ti1/3S2 cathode that delivers a high reversible capacity of ~186 mAh g−1 (0.95 Na) based on the cation and anion redox process. Various charge compensation mechanisms of the sulfur anionic redox process in layered NaCr2/3Ti1/3S2, which occur through the formation of disulfide-like species, the precipitation of elemental sulfur, S–S dimerization, and especially through the formation of electron holes, are investigated. Direct structural evidence for formation of electron holes and (S2)n− species with shortened S–S distances is obtained. These results provide valuable information for the development of materials based on the anionic redox reaction., Anionic redox reactions are gaining interest as a means to optimize capacities of alkaline ion batteries. Here, the authors investigate various charge compensation mechanisms and report S–S dimerization and the formation of electron holes on sulfur in a model sulfide cathode.

This study aims to assess iodine nutritional status and investigate the prevalence of thyroid nodules in children and adolescents in Ningbo city, China. A cross-sectional survey was conducted in Ningbo, China, in 2011. Salt iodine, urine iodine concentration (UIC) and thyroid nodules (by ultrasonography) were measured in 329 participants aged 6–17 years. The median UIC of all participants was 167.23 μg/L. No significant differences in UICs were observed between boys and girls (Z = −1.06, P = 0.29), children and adolescents (Z = −1.88, P = 0.06), iodized salt users and noniodized salt users (Z = −0.10, P = 0.92). A total of 114 nodules with maximum diameters between 1.5 and 12 mm were found among 51 (15.50 %) participants, the prevalence of thyroid nodules between children and adolescents has no significant difference (χ 2 = 0.29, P = 0.59), and there were no significant differences in age (t = 1.56, P = 0.12), gender (χ 2 = 0.13, P = 0.72), type of salt (χ 2 = 0.14, P = 0.71), family history of thyroid diseases (P = 0.46, Fisher’s exact test) and UICs (Z = −1.12, P = 0.26) between the participants with thyroid nodules and those without. The iodine nutrition was adequate in children and adolescents in Ningbo city, but the prevalence of thyroid nodules among children and adolescents was high.

The thermodynamic instability of the layered structure and severe side reactions with liquid carbonate electrolytes have been considered as the key obstacles for the practical application of LiCoO2 (LCO) at voltages of above 4.5 V (versus Li/Li+). Here, we have developed a facile wet-mixing synthetic method which can realize thin and uniform surface coating of aluminum doped zinc oxide (AZO) on LCO particles. The half-cells employing the AZO modified LCO display excellent 4.5 V cycle performance with the discharge capacity retention of 80% after 650 cycles and superior rate capability of 8C capacity of 100 mAh g−1. Combined with surface structure characterizations and bond valence calculations, it is revealed that the stabilized surface and superior kinetic properties contribute to the performance enhancement of AZO modified LCO at 4.5 V. This work demonstrates AZO a suitable coating material for surface protection of cathode materials for high-voltage applications. The preparation method developed in this work is also suitable for mass production and applicable to fabrication of other types of battery materials.

Most technologically important electrode materials for lithium-ion batteries are essentially lithium ions plus a transition-metal oxide framework. However, their atomic and electronic structure evolution during electrochemical cycling remains poorly understood. Here we report the in situ observation of the three-dimensional structural evolution of the transition-metal oxide framework in an all-solid-state battery. The in situ studies LiNi0.5Mn1.5O4 from various zone axes reveal the evolution of both atomic and electronic structures during delithiation, which is found due to the migration of oxygen and transition-metal ions. Ordered to disordered structural transition proceeds along the , , directions and inhomogeneous structural evolution along the direction. Uneven extraction of lithium ions leads to localized migration of transition-metal ions and formation of antiphase boundaries. Dislocations facilitate transition-metal ions migration as well. Theoretical calculations suggest that doping of lower valence-state cations effectively stabilize the structure during delithiation and inhibit the formation of boundaries., Here, with the state-of-the-state electron microscope, the authors report three-dimensional atomic-scale observation of LiNi0.5Mn1.5O4 from various directions, revealing unprecedented insight into the evolution of both atomic and electronic structures during delithiation.

As one of the most promising cathodes for rechargeable sodium-ion batteries (SIBs), O3-type layered transition metal oxides commonly suffer from inevitably complicated phase transitions and sluggish kinetics. Here, a Na[Li0.05 Ni0.3 Mn0.5 Cu0.1 Mg0.05 ]O2 cathode material with the exposed {010} active facets by multiple-layer oriented stacking nanosheets is presented. Owing to reasonable geometrical structure design and chemical substitution, the electrode delivers outstanding rate performance (71.8 mAh g-1 and 16.9 kW kg-1 at 50C), remarkable cycling stability (91.9% capacity retention after 600 cycles at 5C), and excellent compatibility with hard carbon anode. Based on the combined analyses of cyclic voltammograms, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction, the reaction mechanisms behind the superior electrochemical performance are clearly articulated. Surprisingly, Ni2+ /Ni3+ and Cu2+ /Cu3+ redox couples are simultaneously involved in the charge compensation with a highly reversible O3-P3 phase transition during charge/discharge process and the Na+ storage is governed by a capacitive mechanism via quantitative kinetics analysis. This optimal bifunctional regulation strategy may offer new insights into the rational design of high-performance cathode materials for SIBs.

Lithium-rich layered oxides with the capability to realize extraordinary capacity through anodic redox as well as classical cationic redox have spurred extensive attention. However, the oxygen-involving process inevitably leads to instability of the oxygen framework and ultimately lattice oxygen release from the surface, which incurs capacity decline, voltage fading, and poor kinetics. Herein, it is identified that this predicament can be diminished by constructing a spinel Li

As one of the most fascinating cathode candidates for Na-ion batteries (NIBs), P2-type Na layered oxides usually exhibit various single-phase domains accompanied by different Na+/vacancy-ordered superstructures, depending on the Na concentration when explored in a limited electrochemical window. Therefore, their Na+ kinetics and cycling stability at high rates are subjected to these superstructures, incurring obvious voltage plateaus in the electrochemical profiles and insufficient battery performance as cathode materials for NIBs. We show that this problem can be effectively diminished by reasonable structure modulation to construct a completely disordered arrangement of Na-vacancy within Na layers. The combined analysis of scanning transmission electron microscopy, ex situ x-ray absorption spectroscopy, and operando x-ray diffraction experiments, coupled with density functional theory calculations, reveals that Na+/vacancy disordering between the transition metal oxide slabs ensures both fast Na mobility (10-10 to 10-9 cm2 s-1) and a low Na diffusion barrier (170 meV) in P2-type compounds. As a consequence, the designed P2-Na2/3Ni1/3Mn1/3Ti1/3O2 displays extra-long cycle life (83.9% capacity retention after 500 cycles at 1 C) and unprecedented rate capability (77.5% of the initial capacity at a high rate of 20 C). These findings open up a new route to precisely design high-rate cathode materials for rechargeable NIBs.

We demonstrate that Na+/vacancy disordering of P2-type layered cathodes ensures both fast Na mobility and a low Na diffusion barrier., As one of the most fascinating cathode candidates for Na-ion batteries (NIBs), P2-type Na layered oxides usually exhibit various single-phase domains accompanied by different Na+/vacancy-ordered superstructures, depending on the Na concentration when explored in a limited electrochemical window. Therefore, their Na+ kinetics and cycling stability at high rates are subjected to these superstructures, incurring obvious voltage plateaus in the electrochemical profiles and insufficient battery performance as cathode materials for NIBs. We show that this problem can be effectively diminished by reasonable structure modulation to construct a completely disordered arrangement of Na-vacancy within Na layers. The combined analysis of scanning transmission electron microscopy, ex situ x-ray absorption spectroscopy, and operando x-ray diffraction experiments, coupled with density functional theory calculations, reveals that Na+/vacancy disordering between the transition metal oxide slabs ensures both fast Na mobility (10−10 to 10−9 cm2 s−1) and a low Na diffusion barrier (170 meV) in P2-type compounds. As a consequence, the designed P2-Na2/3Ni1/3Mn1/3Ti1/3O2 displays extra-long cycle life (83.9% capacity retention after 500 cycles at 1 C) and unprecedented rate capability (77.5% of the initial capacity at a high rate of 20 C). These findings open up a new route to precisely design high-rate cathode materials for rechargeable NIBs.

As promising high-capacity cathode materials for Na-ion batteries, O3-type Na-based metal oxides always suffer from their poor air stability originating from the spontaneous extraction of Na and oxidation of transition metals when exposed to air. Herein, a combined structure modulation is proposed to tackle concurrently the two handicaps via reducing Na layers spacing and simultaneously increasing valence state of transition metals. Guided by density functional theory calculations, we demonstrate such a modulation can be subtly realized through cosubstitution of one kind of heteroatom with comparable electronegativity and another one with substantially different Fermi level, by adjusting the structure of NaNi0.5Mn0.5O2 via Cu/Ti codoping. The as-obtained NaNi0.45Cu0.05Mn0.4Ti0.1O2 exhibits an increase of 20 times in stable air-exposure period and 9 times in capacity retention after 500 cycles, and even retains its structure and capacity after being soaked in water. Such a simple and effective structure mo...

Sodium-ion batteries (SIBs) have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. O3-type layered oxides have been considered as one of the most promising cathodes for SIBs. However, they commonly show inevitable complicated phase transitions and sluggish kinetics, incurring rapid capacity decline and poor rate capability. Here, a series of sodium-sufficient O3-type NaNi

Li(Ni0.6Co0.2Mn0.2)O2 has been surface-modified by the lithium-ion conductor Li1.4)Al0.4)Ti1.6)(PO4)3 via a facile mechanical fusion method. The annealing temperature during coating process shows a strong impact on the surface morphology and chemical composition of Li(Ni0.6Co0.2Mn0.2)O2. The 600-°C annealed material exhibits the best cyclic stability at high charging cut-off voltage of 4.5 V (versus Li + /Li) with the capacity retention of 90.9% after 100 cycles, which is much higher than that of bare material (79%). Moreover, the rate capability and thermal stability are also improved by Li1.4)Al0.4)Ti1.6)(PO4)3 coating. The enhanced performance can be attributed to the improved stability of interface between Li(Ni0.6Co0.2Mn0.2)O2 and electrolyte by Li1.4)Al0.4)Ti1.6)(PO4)3 modification. The results of this work provide a possible method to design reliable cathode materials to achieve high energy density and long cycle life.

Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li2MnO3·0.5LiNi0.8Co0.1Mn0.1O2 with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn-Teller effect of active Mn(3+) ions, improving d-p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density.

The effects of tungsten W doping and coating on the electrochemical performance of LiCoO2 cathode are comparatively studied in this work. The amount of modification component is as low as 0.1 wt% and 0.3 wt% respectively. After 100 cycles between 3.0 V–4.6 V, 0.1 wt% W doping provides an optimized capacity retention of 72.3%. However, W coating deteriorates battery performance with capacity retention of 47.8%, even lower than bare LiCoO2 of 55.7%. These different electrochemical performances can be attributed to the surface aggregation of W between doping and coating methods. W substitution is proved to be a promising method to develop high voltage cathodes. Practical performance relies on detailed synthesis method.

Lithium-rich layered oxides with the capability to realize extraordinary capacity through anodic redox as well as classical cationic redox have spurred extensive attention. However, the oxygen-involving process inevitably leads to instability of the oxygen framework and ultimately lattice oxygen release from the surface, which incurs capacity decline, voltage fading, and poor kinetics. Herein, it is identified that this predicament can be diminished by constructing a spinel Li4 Mn5 O12 coating, which is inherently stable in the lattice framework to prevent oxygen release of the lithium-rich layered oxides at the deep delithiated state. The controlled KMnO4 oxidation strategy ensures uniform and integrated encapsulation of Li4 Mn5 O12 with structural compatibility to the layered core. With this layer suppressing oxygen release, the related phase transformation and catalytic side reaction that preferentially start from the surface are consequently hindered, as evidenced by detailed structural evolution during Li+ extraction/insertion. The heterostructure cathode exhibits highly competitive energy-storage properties including capacity retention of 83.1% after 300 cycles at 0.2 C, good voltage stability, and favorable kinetics. These results highlight the essentiality of oxygen framework stability and effectiveness of this spinel Li4 Mn5 O12 coating strategy in stabilizing the surface of lithium-rich layered oxides against lattice oxygen escaping for designing high-performance cathode materials for high-energy-density lithium-ion batteries.

Context. The quiet Sun is an important part of understanding the global magnetic properties of the Sun. A recently launched observation system, named HINODE, provides a lot of high-resolution images for studying the quiet Sun. Obviously, it is time-consuming to analyze these images by hand. It is desirable to develop a technique for recognizing magnetic elements, thus automatically computing magnetic properties and the relationship between magnetic elements and granulation. Aims. We design an automatic method of recognizing magnetic elements based on the features of HINODE magnetograms and of measuring their properties. Then we study the relationship between magnetic elements and granulation. Methods. We used the magnetogram, continuum image, and Dopplergram on April 16, 2007, which were taken with the Solar Optical Telescope instrument aboard HINODE. The field of view is 147. 60 × 162. �� 30 in a quiet solar region, locating at disk center. We introduced the mark-controlled watershed method to detect magnetic elements automatically, because it is a popular image-segmentation method for dealing with overlapping objects. We took the centers that are the local maximum in all directions as the marks for restraining over-segmentation. We computed the properties of the detected magnetic elements and the relation among magnetic field strength, relative continuum intensity, and Doppler velocity at the same locations of magnetic elements. Results. We obtain the following results: (1) 34% of our observation region are covered by magnetic fields; (2) the magnetic flux distribution of all elements reaches a peak at 1.07 × 10 16 Mx for the whole region; (3) the relative continuum intensity distribution at the locations of magnetic elements reaches a peak at 0.97, which shows that the majority of magnetic elements located at the areas where the relative continuum intensity is less than its average. The relative continuum intensities in the areas with strong flux density are the median, meaning that the strong magnetic elements are usually located at the boundary of granulation; (4) the absolute Doppler velocity distribution at the locations of magnetic elements reaches a peak at 1.00 km s −1 , and the majority of weak magnetic elements located at the areas where the absolute velocity is greater than 1.00 km s −1 ; (5) strongly magnetized regions only have weak absolute Doppler velocities. The absolute velocity is lower than 1.00 km s −1 in the regions where the magnetic flux density of elements is

Based on SOHO/MDI, EIT, Yohkoh/SXT, Hα , and other relevant observations, we analyzed all the earth-directed halo coronal mass ejections (CMEs) in the interval from Mar. 1997 to Dec. 2003. A total of 288 earth-directed CMEs were studied and their associated surface activity events identified. Unlike the previous studies that often attributed a surface activity event or a given active region to a CME source region, this statistical analysis puts emphasis on the large-scale magnetic structures of CMEs, in which the CME-associated surface activity takes place. All the CMEs are found to be associated with large-scale source structures. The identified large-scale structures can be grouped into four different categories: extended bipolar regions (EBRs), transequatorial magnetic loops, transequatorial filaments and their associated magnetic structures, and long filaments along the boundaries of EBRs. The relative percentages of their associated CMEs are 36%, 40%, 13%, and 11%, respectively. The analysis indicates that CMEs are intrinsically associated with source magnetic structures on a large spatial scale.

Developing high energy density lithium ion battery cathode materials requires exploring novel chemistries that go beyond the conventional redox couple which is solely based on transition metal. Anionic redox reaction that activates lattice oxygen anions during charging and discharging can almost double the capacity of conventional cathode and thereby significantly increases the energy density. The nature of chemical bonding, in particular whether or not oxygen anions can bond in forming dimers or peroxo-like species, is critical to the reversibility of anionic redox couple and consequent cyclability of the material. Unfortunately, because oxygen scatters X-ray weakly and dimers may form locally rather than globally, it is very challenging to characterize the oxygen-oxygen bond unambiguously using conventional structural study tools like XRD. Here it is shown that neutron pair distribution function (NPDF) analysis is an effective tool in probing the existence of oxygen dimers without limitation to long range order. This technique is applied to LiCoO2 which still attracts lots of attention due to its high packing density and potential high energy density (delivers around 220 mAh/g when charged to 4.6 V). Through combining experimental results with theoretical calculations, the nature of anionic redox reaction is unraveled and it is shown that the structure of LiCoO2 can be fairly robust against oxygen release, suggesting the relative stability of the bulk structure and the possibility of fulfilling its potential of high energy density. Acknowledgement The work done at Brookhaven National Laboratory were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under contract DE-SC0012704. Research conducted at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

Sodium-ion batteries (SIBs) have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. O3-type layered oxides have been considered as one of the most promising cathodes for SIBs. However, they commonly show inevitable complicated phase transitions and sluggish kinetics, incurring rapid capacity decline and poor rate capability. Here, a series of sodium-sufficient O3-type NaNi0.5 Mn0.5-x Ti x O2 (0 ≤ x ≤ 0.5) cathodes for SIBs is reported and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end-members. The combined analysis of in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, and scanning transmission electron microscopy for NaNi0.5 Mn0.2 Ti0.3 O2 reveals that the O3-type phase transforms reversibly into a P3-type phase upon Na+ deintercalation/intercalation. The substitution of Ti for Mn enlarges interslab distance and could restrain the unfavorable and irreversible multiphase transformation in the high voltage regions that is usually observed in O3-type NaNi0.5 Mn0.5 O2 , resulting in improved Na cell performance. This integration of macroscale and atomicscale engineering strategy might open up the modulation of the chemical and physical properties in layered oxides and grasp new insight into the optimal design of high-performance cathode materials for SIBs.

Serum samples were collected from 2643 suspected cases of paragonimiasis in 2000-2007 from the outpatient departments of the city hospitals and surrounding areas, and the infection rate in the inhabitants, the first and second intermediate hosts, and animal reservoir hosts were investigated in the historical endemic areas. Serum samples were detected and 417 were found antibody positive (15.8%). Among residents in the historical endemic areas, the seropositive rate was 3.1% (46/1462), 2.8% (18/649) and 3.2% (26/813) in males and females respectively (CHI2 = 0.1833, P0.05). The infection rate in first intermediate host (snails), second intermediate host (crabs) and animal reservoir hosts was 0.05% (9/ 19,368), 31.1% (15,627/ 50,313) and 11.9% (52/438) respectively. Evidently, natural nidi for Paragonimus spp. still exist in Ningbo City.

Using the 15-m Swedish ESO Sub-millimeter Telescope (SEST), CO, HCN, and HCO+ observations of the galactic star-forming region NGC6334 FIR II are presented, complemented by [C I] 3^P_1--3^P_0 and 3^P_2--3^P_1 data from the Atacama Pathfinder Experiment (APEX 12-m telescope). Embedded in the extended molecular cloud and associated with the H II region NGC6334--D, there is a molecular "void". [C I] correlates well with 13^CO and other molecular lines and shows no rim brightening relative to molecular cloud regions farther off the void. While an interpretation in terms of a highly clumped cloud morphology is possible, with photon dominated regions (PDRs) reaching deep into the cloud, the data do not provide any direct evidence for a close association of [C I] with PDRs. Kinetic temperatures are ~40--50K in the molecular cloud and >=200K toward the void. CO and [C I] excitation temperatures are similar. A comparison of molecular and atomic fine structure line emission with the far infrared and radio continuum as well as the distribution of 2.2um H_2 emission indicates that the well-evolved H II region expands into a medium that is homogeneous on pc-scales. If the H_2 emission is predominantly shock excited, both the expanding ionization front (classified as subsonic, "D-type") and the associated shock front farther out (traced by H_2) can be identified, observationally confirming for the first time a classical scenario that is predicted by evolutionary models of H II regions. Integrated line intensity ratios of the observed molecules are determined, implying a mean C18^O/C17^O abundance ratio of 4.13+-0.13 that reflects the 18^O/17^O isotope ratio. This ratio is consistent with values determined in nearby clouds. Right at the edge of the void, however, the oxygen isotope ratio might be smaller., 18 pages, 13 figures, 3 tables, A&A in press

{Magnetic fields exist on all scales in our Galaxy. There is a controversy about whether the magnetic fields in molecular clouds are preserved from the permeated magnetic fields in the interstellar medium (ISM) during cloud formation. We investigate this controversy using available data in the light of the newly revealed magnetic field structure of the Galactic disk obtained from pulsar rotation measures (RMs).} % {We collected measurements of the magnetic fields in molecular clouds, including Zeeman splitting data of OH masers in clouds and OH or HI absorption or emission lines of clouds themselves.} % {The Zeeman data show structures in the sign distribution of the line-of-sight component of the magnetic field. Compared to the large-scale Galactic magnetic fields derived from pulsar RMs, the sign distribution of the Zeeman data shows similar large-scale field reversals. Previous such examinations were flawed in the over-simplified global model used for the large-scale magnetic fields in the Galactic disk.} % {We conclude that the magnetic fields in the clouds may still ``remember'' the directions of magnetic fields in the Galactic ISM to some extent, and could be used as complementary tracers of the large-scale magnetic structure. More Zeeman data of OH masers in widely distributed clouds are required.}, Typo fixed in this new version