Evaulation of irritation potential of surfactant mixtures

Irritation potential of sodium laureth sulfate (SLES) alone, and in combination with lauryl glucoside (LG), polysorbate 20 (PS) and cocoamidopropyl betaine (CAPB) was tested in 13 human subjects. Four main and six sub-formulations were prepared and evaluated. Formulations were applied to the forearm as a 24 h close patch study. Irritation was scored by two different methods using an in vivo clinical protocol based on visual scoring and on the stratum corneum capacitance measurement. Irritation was found to be dose dependent. At 2 mg/patch level ten subjects did not show any skin reaction. At 20 mg/patch level eleven subjects showed a broad range of skin irritation. The highest irritation was observed with the formula that contained SLES, LG, and cocamide DEA together. Among the sub-formulations, cocamide DEA showed the highest irritation grade. A statistically significant correlation was observed between visual, clinical and corneometer scores. It was concluded that the irritation potential of surfactants was related to the total surfactant concentration, application mode, and the thermodynamic activity of molecules in the solution as well as the chemical structure of the surfactant molecules.     

A Water Stable,Near‐Zero‐Strain O3‐Layered Titanium‐Based Anode for Long Cycle Sodium‐Ion Battery

Layered transition metal (TM) oxides of the stoichiometry Na_xMO₂ (M = TM) have shown great promise in sodium‐ion batteries (SIBs); however, they are extremely sensitive to moisture. To date, most reported titanium‐based layered anodes exhibit a P2‐type structure. In contrast, O3‐type compounds are rarely investigated and their synthesis is challenging due to their higher percentage of unstable Ti³⁺ than the P2 type. Here, a pure phase and highly crystalline O3‐type Na_0.73Li_0.36Ti_0.73O₂ with high performance is successfully proposed in SIBs. This material delivers a reversible capacity of 108 mAh g^?1 with a stable and safe potential of 0.75 V versus Na/Na⁺. In situ X‐ray diffraction reveals that this material does not undergo any phase transitions and exhibits a near‐zero volume change upon Na⁺ insertion/de‐insertion, which ensures exceptional long cycle life over 6000 cycles. Importantly, it is found that this O3‐Na_0.73Li_0.36Ti_0.73O₂ shows superior moisture stability, even when immersed into water, which are both elusive for conventional layered TM oxides in SIBs. It is believed that the small interlayer distance and high occupation of interlayer vacancy promise such unprecedented water stability.     

Boosting Piezo-Catalytic Activity of KNN-Based Materials with Phase Boundary and Defect Engineering

Although the piezo-catalysis is promising for the environmental remediation and biomedicine, the piezo-catalytic properties of various piezoelectric materials are limited by low carrier concentrations and mobility, and rapid electron-hole pair recombination, and reported regulating strategies are quite complex and difficult. Herein, a new and simple strategy, integrating phase boundary engineering and defect engineering, to boost the piezo-catalytic activity of potassium sodium niobate ((K, Na)NbO₃, KNN) based materials is innovatively proposed. Tur strategy is validated by exampling 0.96(K_0.48Na_0.52)Nb_0.955Sb_0.045O₃-0.04(Bi_xNa_4-3x)_0.5ZrO₃-0.3%Fe₂O₃ material having phase boundary engineering and conducted the defect engineering via the high-energy sand-grinding. A high reaction rate constant k of 92.49 × 10⁻³ min⁻¹ in the sand-grinding sample is obtained, which is 2.40 times than that of non-sand-grinding one and superior to those of other representative lead-free perovskite piezoelectric materials. Meanwhile, the sand-grinding sample has remarkable bactericidal properties against Escherichia coli and Staphylococcus aureus. Superior piezo-catalytic activities originate from the enhanced electron-hole pair separation and the increased carrier concentration. This study provides a novel method for improving the piezo-catalytic activities of lead-free piezoelectric materials and holds great promise for harnessing natural energy and disease treatment.     

Constructing CoO/Co3S4 Heterostructures Embedded in N‐doped Carbon Frameworks for High‐Performance Sodium‐Ion Batteries

Heterostructures are attractive for advanced energy storage devices due to their rapid charge transfer kinetics, which is of benefit to the rate performance. The rational and facile construction of heterostructures with satisfactory electrochemical performance, however, is still a great challenge. Herein, ultrafine hetero‐CoO/Co₃S₄ nanoparticles embedded in N‐doped carbon frameworks (CoO/Co₃S₄@N‐C) are successfully obtained by employing metal‐organic frameworks as precursors. As anodes for sodium ion batteries, the CoO/Co₃S₄@N‐C electrodes exhibit high specific capacity (1029.5 mA h g^?1 at 100 mA g^?1) and excellent rate capability (428.0 mA h g^?1 at 5 A g^?1), which may be attributed to their enhanced electric conductivity, facilitated Na⁺ transport, and intrinsic structural stability. Density functional theoretical calculations further confirm that the constructed heterostructures induce electric fields and promote fast reaction kinetics in Na⁺ transport. This work provides a feasible approach to construct metal oxide/sulfide heterostructures toward high‐performance metal‐ion batteries.     

Recent Advances in Mn-Rich Layered Materials for Sodium-Ion Batteries

Branded with low cost and a high degree of safety, with an ambitious aim of substituting lithium-ion batteries in many fields, sodium-ion batteries have received fervid attention in recent years after being dormant for decades. Layered materials are a major focus of study owing to the extensive experience already gained in lithium-ion batteries, and the pursuit of a Mn-rich composition is critical to reduce the cost while retaining the performance. This review provides a timely update of the recent progress of Mn-rich layered materials for sodium-ion batteries based on the understandings of the phase forming principles, structure transformation upon cycling and charge compensation mechanisms and discusses potential ambiguities in the pursuit of high-performance materials.     

以Na2TeO3为碲源制备CdTe纳米晶及其表征

本文以巯基乙酸作为稳定剂,在水相中制备了CdTe纳米晶。以亚碲酸钠作为碲源,从而避免了以H2Te或NaHTe（用碲粉和硼氢化钠合成）作为碲源时,需要氮气或其它气体作为保护气体的过程,简化了制备工艺,并且提高了CdTe纳米晶的产量。用X射线衍射仪（XRD）、透射电镜（SEM）和荧光分光光度计对其进行了表征。分析表明CdTe纳米晶为立方相,并且有较窄的荧光发射峰。详细探讨了反应时间、pH值及前驱物浓度对CdTe纳米晶荧光性能的影响。     

氯化钠晶体注入着色

用自制的电注入装置,对氯化钠（NaCl）晶体进行电注入并使之有效着色,在晶体中产生F色心、胶体（C）心和一些未知色心。采用3种不同条件对NaCl晶体进行电注入,详细研究了温度和电压对色心浓度的影响。研究结果表明,随着温度和电压的升高,色心的浓度增大,并且存晶体不同部位,相应色心浓度不同。     

In Situ X‐Ray Diffraction Studies on Structural Changes of a P2 Layered Material during Electrochemical Desodiation/Sodiation

Sodium layered oxides with mixed transition metals have received significant attention as positive electrode candidates for sodium‐ion batteries because of their high reversible capacity. The phase transformations of layered compounds during electrochemical reactions are a pivotal feature for understanding the relationship between layered structures and electrochemical properties. A combination of in situ diffraction and ex situ X‐ray absorption spectroscopy reveals the phase transition mechanism for the ternary transition metal system (Fe–Mn–Co) with P2 stacking. In situ synchrotron X‐ray diffraction using a capillary‐based microbattery cell shows a structural change from P2 to O2 in P2–Na_0.7Fe_0.4Mn_0.4Co_0.2O₂ at the voltage plateau above 4.1 V on desodiation. The P2 structure is restored upon subsequent sodiation. The lattice parameter c in the O2 structure decreases significantly, resulting in a volumetric contraction of the lattice toward a fully charged state. Observations on the redox behavior of each transition metal in P2–Na_0.7Fe_0.4Mn_0.4Co_0.2O₂ using X‐ray absorption spectroscopy indicate that all transition metals are involved in the reduction/oxidation process.     

High‐Performance Cathode Based on Self‐Templated 3D Porous Microcrystalline Carbon with Improved Anion Adsorption and Intercalation

Dual‐ion batteries (DIBs) have attracted much attention due to their advantages of low cost and especially environmental friendliness. However, the capacities of most DIBs are still unsatisfied (≈100 mAh g^?1) ascribed to the limited capacity of anions intercalation for conventional graphite cathode. In this study, 3D porous microcrystalline carbon (3D‐PMC) was designed and synthesized via a self‐templated growth approach, and when used as cathode for a DIB, it allows both intercalation and adsorption of anions. The microcrystalline carbon is beneficial to obtain capacity originated from anions intercalation, and the 3D porous structure with a certain surface area contributes to anions adsorption capacity. With the synergistic effect, this 3D‐PMC is utilized as cathode and tin as anode for a sodium‐based DIB, which has a high capacity of 168.0 mAh g^?1 at 0.3 A g^?1, among the best values of reported DIBs so far. This cell also exhibits long‐term cycling stability with a capacity retention of ≈70% after 2000 cycles at a high current rate of 1 A g^?1. It is believed that this work will provide a strategy to develop high‐performance cathode materials for DIBs.     

All‐Cellulose‐Based Quasi‐Solid‐State Sodium‐Ion Hybrid Capacitors Enabled by Structural Hierarchy

Na‐ion hybrid capacitors consisting of battery‐type anodes and capacitor‐style cathodes are attracting increasing attention on account of the abundance of sodium‐based resources as well as the potential to bridge the gap between batteries (high energy) and supercapacitors (high power). Herein, hierarchically structured carbon materials inspired by multiscale building units of cellulose from nature are assembled with cellulose‐based gel electrolytes into Na‐ion capacitors. Nonporous hard carbon anodes are obtained through the direct thermal pyrolysis of cellulose nanocrystals. Nitrogen‐doped carbon cathodes with a coral‐like hierarchically porous architecture are prepared via hydrothermal carbonization and activation of cellulose microfibrils. The reversible charge capacity of the anode is 256.9 mAh g^?1 when operating at 0.1 A g^?1 from 0 to 1.5 V versus Na⁺/Na, and the discharge capacitance of cathodes tested within 1.5 to 4.2 V versus Na⁺/Na is 212.4 F g^?1 at 0.1 A g^?1. Utilizing Na⁺ and ClO₄^? as charge carriers, the energy density of the full Na‐ion capacitor with two asymmetric carbon electrodes can reach 181 Wh kg^?1 at 250 W kg^?1, which is one of the highest energy devices reported until now. Combined with macrocellulose‐based gel electrolytes, all‐cellulose‐based quasi‐solid‐state devices are demonstrated possessing additional advantages in terms of overall sustainability.