Advances in Polar Materials for Lithium-Sulfur Batteries

Lithium-sulfur batteries are regarded as promising candidates for energy storage devices due to their high theoretical energy density. Various approaches are proposed to break through the obstacles that are preventing Li-S batteries from realizing practical application. Recently, the importance of the strong chemical interaction between polar materials and polysulfides is recognized by researchers to improve the performance of Li-S batteries, especially with respect to the shuttle effect. Polar materials, unlike nonpolar materials, exhibit strong interactions with polysulfides without any modification or doping because of their intrinsic polarity, absorbing the polar polysulfides and thus suppressing the notorious shuttle effect. The recent advances on polar materials for Li-S batteries are reviewed here, especially the chemical polar-polar interaction effects toward immobilizing dissolved polysulfides, and the relationship between the intrinsic properties of the polar materials and the electrochemical performance of the Li-S batteries are discussed. Polar materials, including polar inorganics in the cathode and polar organics as binder for the Li-S batteries are respectively described. Finally, future directions and prospects for the polar materials used in Li-S batteries are also proposed

Relationship between Thermal Conductivity and Compressive Strength of Insulation Concrete: A Review

Developing insulation concrete with high strength is essential for the construction of energy saving buildings. This is important to achieve carbon neutrality in the modern building industry. This paper reviews the existing studies in the literature on insulation concrete. This paper aims to reveal the correlation between the thermal conductivity and strength of concrete and identify the most effective method to make insulation concrete with lower thermal conductivity but higher strength. The review is carried out from two perspectives, including the effects of different foaming methods and various lightweight aggregates. As for the foaming methods, the chemical and mechanical foaming methods are discussed. As for the lightweight aggregates, cenospheres, porous aggregates, aerogels, and phase change materials are assessed. It is clearly observed that the thermal conductivity and compressive strength of concrete can be fitted by a linear function. As for the foaming methods, chemical foaming using hydrogen peroxide is the most effective to produce concrete with relatively lower thermal conductivity and higher compressive strength. For concrete with lightweight aggregates, cenospheres are the best option. Finally, recommendations are made to develop concrete with lower thermal conductivity and higher strength

Strong affinity of polysulfide intermediates to multi-functional binder for practical application in lithium-sulfur batteries

Binder, one of the most important battery components, plays a critical role in lithium-sulfur batteries. Poly(vinylidene difluoride) (PVDF), a commonly used binder in lithium-sulfur batteries, does not have a strong affinity to the intermediate polysulfides, however, leading to fast capacity fading with electrochemical cycling. Herein, copolymers of vinylidene difluoride with other monomers are used as multi-functional binders to enhance the electrochemical performance of lithium-sulfur batteries. Compared to the PVDF, the copolymer, poly(vinylidene difluoride-trifluoroethylene) (P(VDF-TRFE)) binder exhibits higher adhesion strength, less porosity, and stronger chemical interaction with polysulfides, which helps to keep the polysulfides within the cathode region, thereby improving the electrochemical performance of the lithium-sulfur battery. As a result, sulfur electrode with P(VDF-TRFE) binder delivered a high capacity of 801 mA h g-1 at 0.2 C after 100 cycles, which is nearly 80% higher capacity than the corresponding sulfur cathode with PVDF binder

A new energy storage system: Rechargeable potassium-selenium battery

A new reversible and high-performance potassium-selenium (K-Se) battery, using confined selenium/carbonized-polyacrylonitrile (PAN) composite (c-PAN-Se) as cathode and metallic potassium as anode, is reported in this work. The PAN-derived carbon matrix could effectively confine the small Se molecules and provide a sufficient buffer for the volume changes. The reversible formation of small-molecule trigonal Se (Se1, P3121) phase could essentially inhibit the formation of polyselenides and account for outstanding electrochemical performance. The carbonate-based electrolyte further synergistically diminishes the shuttle effect by inhibiting the formation of polyselenides in the meantime. The as-prepared K-Se battery shows a reversible capacity of 1904 mAh cm¿3after 100 cycles at 0.2 C and rate retention of 89% from 0.1 to 2 C. In addition, the charge-discharge mechanism is also investigated via the combination of in-situ and ex-situ synchrotron X-ray diffraction (XRD), and Raman spectroscopy analysis. The results reveal that the introduction of K+ions leads to the cleavage of C-Se bonds, the rearrangement of selenium atoms, and the final formation of the main product K2Se. Moreover, the reversible formation of trigonal Se (Se1, P3121) phase was detected in the reaction with K+. These findings not only can advance our understanding of this family of batteries, but also provide insight into chemically-bonded selenium composite electrodes, which could give guidance for scientific research and the optimization of Se and S electrodes for the K-S, Na-S, Li-S, Na-Se, and Li-Se batteries

Fasudil in Combination With Bone Marrow Stromal Cells (BMSCs) Attenuates Alzheimer\u27s Disease-Related Changes Through the Regulation of the Peripheral Immune System.

Alzheimer\u27s disease (AD) is a chronic progressive neurodegenerative disease. Its mechanism is still not clear. Majority of research focused on the central nervous system (CNS) changes, while few studies emphasize on peripheral immune system modulation. Our study aimed to investigate the regulation of the peripheral immune system and its relationship to the severity of the disease after treatment in an AD model of APPswe/PSEN1dE9 transgenic (APP/PS1 Tg) mice. APP/PS1 Tg mice (8 months old) were treated with the ROCK-II inhibitor 1-(5-isoquinolinesulfonyl)-homo-piperazine (Fasudil) (intraperitoneal (i.p.) injections, 25 mg/kg/day), bone marrow stromal cells (BMSCs; caudal vein injections, 1 × 1

Study on the characteristics of mold in military aviation material warehouse

Aviation equipment warehouse is responsible for the combat training task of the army. The existence of mold in the warehouse reduces the quality and performance of equipment, and the quality of storage equipment directly affects the strength of aviation equipment support ability. In this paper, the main characteristics of storage mold were studied, the micro morphology and colony characteristics of storage mold were analyzed, and the main types of mold in aviation material warehouse were introduced, which provided a theoretical basis for further research on the growth and control of mold

Wet-Chemical Synthesis of Surface-Passivated Halide Perovskite Microwires for Improved Optoelectronic Performance and Stability

One-dimensional (1D) halide perovskite materials with intrinsic high carrier mobility and long diffusion length hold great promises for high-performance optoelectronic devices, in which the passivation of the surface defects is of significance for further boosting its optoelectronic performance as well as its moisture stability. Herein, we demonstrate a simple room-temperature wet-chemical synthetic protocol for perovskite microwires with controlled morphologies and passivated surface states. This strategy allows for facile assembly of hydrophobic 1<i>H</i>,1<i>H</i>-perfluorooctylamine (PFA) molecules on the surface of the perovskite microwires owing to the coordination binding between the amino groups of PFA and Pb²⁺. Both steady and time-resolved photoluminescence measurements revealed that the passivation of PFA greatly benefit for the inhibition of the photogenerated carriers recombination. The constructed perovskite microwire-based photodetectors have shown increased detectivity of 4.99 × 10¹¹ jones and responsivity of 1.27 A/W (light power density of 1 mW/cm²). Moreover, the hydrophobic fluorocarbon alkyl chains endow the perovskite microwires with higher resistance toward moisture. Such coating of a water-resisting layer resulted in greatly enhanced stability of perovskite microwires under the humidity of 55 ± 5% over 30 days. We thus believe that our work is of importance for the development of 1D halide perovskite photodetectors with highly improved performance and stability

Fasudil in Combination With Bone Marrow Stromal Cells (BMSCs) Attenuates Alzheimer’s Disease-Related Changes Through the Regulation of the Peripheral Immune System

Alzheimer’s disease (AD) is a chronic progressive neurodegenerative disease. Its mechanism is still not clear. Majority of research focused on the central nervous system (CNS) changes, while few studies emphasize on peripheral immune system modulation. Our study aimed to investigate the regulation of the peripheral immune system and its relationship to the severity of the disease after treatment in an AD model of APPswe/PSEN1dE9 transgenic (APP/PS1 Tg) mice. APP/PS1 Tg mice (8 months old) were treated with the ROCK-II inhibitor 1-(5-isoquinolinesulfonyl)- homo-piperazine (Fasudil) (intraperitoneal (i.p.) injections, 25 mg/kg/day), bone marrow stromal cells (BMSCs; caudal vein injections, 1 × 106 BMSCs /time/mouse), Fasudil combined with BMSCs, or saline (i.p., control) for 2 months. Morris water maze (MWM) test was used to evaluate learning and memory. The mononuclear cells (MNCs) of spleens of APP/PS1 Tg mice were analyzed using flow cytometry for CD4+ T-cells, macrophages, and the pro-inflammatory and anti-inflammatory molecules of the macrophages. Immunohistochemical staining was used to examine the expression of ROCK-II in the spleens of APP/PS1 Tg mice. The MWM test showed improved spatial learning ability in APP/PS1 Tg mice treated with Fasudil or BMSCs alone or in combination, compared to untreated APP/PS1 Tg mice. Fasudil combined with BMSCs intervention significantly promoted the proliferation of CD4+/CD25+ and CD4+/ IL-10 lymphocytes, induced the release of cytokine factors, and regulated the balance of the immune system to work functionally. It also shifted M1 (MHC-II, CD86) to M2 (IL-10, CD206) phenotype of macrophages of CD11b and significantly enhanced the anti-inflammatory and phagocytic abilities (CD16/32) of macrophages of CD11b. Immunohistochemical staining showed significantly decreased expression of ROCK-II in mice treated with combination of Fasudil with BMSCs as compared to saline control. Fasudil in combination of BMSCs improved cognition of APP/PS1 Tg mice through the regulation of the peripheral immune system, including reduction of ROCK-II expression and increased proportion of anti-inflammatory M2 mononuclear phenotype and phagocytic macrophages in the spleen of the peripheral immune system. The latter was achieved through the communication between brain and spleen to improve the immunoregulation of CNS and AD disease conditions