Single‐Ion Conducting Electrolyte Based on Electrospun Nanofibers for High‐Performance Lithium Batteries

Herein, a novel electrospun single‐ion conducting polymer electrolyte (SIPE) composed of nanoscale mixed poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and lithium poly(4,4′‐diaminodiphenylsulfone, bis(4‐carbonyl benzene sulfonyl)imide) (LiPSI) is reported, which simultaneously overcomes the drawbacks of the polyolefin‐based separator (low porosity and poor electrolyte wettability and thermal dimensional stability) and the LiPF₆ salt (poor thermal stability and moisture sensitivity). The electrospun nanofiber membrane (es‐PVPSI) has high porosity and appropriate mechanical strength. The fully aromatic polyamide backbone enables high thermal dimensional stability of es‐PVPSI membrane even at 300 °C, while the high polarity and high porosity ensures fast electrolyte wetting. Impregnation of the membrane with the ethylene carbonate (EC)/dimethyl carbonate (DMC) (v:v = 1:1) solvent mixture yields a SIPE offering wide electrochemical stability, good ionic conductivity, and high lithium‐ion transference number. Based on the above‐mentioned merits, Li/LiFePO₄ cells using such a SIPE exhibit excellent rate capacity and outstanding electrochemical stability for 1000 cycles at least, indicating that such an electrolyte can replace the conventional liquid electrolyte–polyolefin combination in lithium ion batteries (LIBs). In addition, the long‐term stripping–plating cycling test coupled with scanning electron microscope (SEM) images of lithium foil clearly confirms that the es‐PVPSI membrane is capable of suppressing lithium dendrite growth, which is fundamental for its use in high‐energy Li metal batteries.     

Confined Fe2VO4⊂Nitrogen‐Doped Carbon Nanowires with Internal Void Space for High‐Rate and Ultrastable Potassium‐Ion Storage

Developing low‐cost, high‐capacity, high‐rate, and robust earth‐abundant electrode materials for energy storage is critical for the practical and scalable application of advanced battery technologies. Herein, the first example of synthesizing 1D peapod‐like bimetallic Fe₂VO₄ nanorods confined in N‐doped carbon porous nanowires with internal void space (Fe₂VO₄?NC nanopeapods) as a high‐capacity and stable anode material for potassium‐ion batteries (KIBs) is reported. The peapod‐like Fe₂VO₄?NC nanopeapod heterostructures with interior void space and external carbon shell efficiently prevent the aggregation of the active materials, facilitate fast transportation of electrons and ions, and accommodate volume variation during the cycling process, which substantially boosts the rate and cycling performance of Fe₂VO₄. The Fe₂VO₄?NC electrode exhibits high reversible specific depotassiation capacity of 380 mAh g^?1 at 100 mA g^?1 after 60 cycles and remarkable rate capability as well as long cycling stability with a high capacity of 196 mAh g^?1 at 4 A g^?1 after 2300 cycles. The first‐principles calculations reveal that Fe₂VO₄?NC nanopeapods have high ionic/electronic conductivity characteristics and low diffusion barriers for K⁺‐intercalation. This study opens up new way for investigating high‐capacity metal oxide as high‐rate and robust electrode materials for KIBs.     

Co–B Nanoflakes as Multifunctional Bridges in ZnCo2O4 Micro‐/Nanospheres for Superior Lithium Storage with Boosted Kinetics and Stability

Transition metal oxides hold great promise as high‐energy anodes in next‐generation lithium‐ion batteries. However, owing to the inherent limitations of low electronic/ionic conductivities and dramatic volume change during charge/discharge, it is still challenging to fabricate practically viable compacted and thick TMO anodes with satisfactory electrochemical performance. Herein, with mesoporous cobalt–boride nanoflakes serving as multifunctional bridges in ZnCo₂O₄ micro‐/nanospheres, a compacted ZnCo₂O₄/Co–B hybrid structure is constructed. Co–B nanoflakes not only bridge ZnCo₂O₄ nanoparticles and function as anchors for ZnCo₂O₄ micro‐/nanospheres to suppress the severe volume fluctuation, they also work as effective electron conduction bridges to promote fast electron transportation. More importantly, they serve as Li⁺ transfer bridges to provide significantly boosted Li⁺ diffusivity, evidenced from both experimental kinetics analysis and density functional theory calculations. The mesopores within Co–B nanoflakes help overcome the large Li⁺ diffusion barriers across 2D interfaces. As a result, the ZnCo₂O₄/Co–B electrode delivers high gravimetric/volumetric/areal capacities of 995 mAh g^?1/1450 mAh cm^?3/5.10 mAh cm^?2, respectively, with robust rate capability and long‐term cyclability. The distinct interfacial design strategy provides a new direction for designing compacted conversion‐type anodes with superior lithium storage kinetics and stability for practical applications.     

Expansion of Islet-Resident Macrophages Leads to Inflammation Affecting β Cell Proliferation and Function in Obesity

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Review of ammonia-oxidizing bacteria and archaea in freshwater ponds

Aquaculture ponds are simple and unique ecosystems, which are affected intensively by human activities. In this mini-review, we focus our attention on the distribution and community diversity of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in pond water and sediments, as well as the possible ecological mechanisms involved. Moreover, we discuss the possibility of increasing the activity of ammonia-oxidizing organisms in order to improve the water quality in aquaculture ponds. Compared with eutrophic lakes, the significantly higher ammonia concentration in pond water does not lead to significantly higher AOB levels, and the abundance of AOA is too low to quantify accurately. Similar to eutrophic lakes, high abundances of AOA and AOB are present in the surface sediments at the same time, where the oxidation of ammonia is performed mainly by AOB. AOB and AOA exhibit significant seasonal variations in aquaculture ponds, which are affected by the temperature, pH, and dissolved oxygen. The dominant AOB species are Nitrosomonas and the Nitrosospira lineage in pond environments. Nitrososphaera or members of the Nitrososphaera-like cluster dominate the AOA species in surface sediments, whereas the Nitrosopumilus cluster dominates the deeper sediments. AOB and AOA can be enriched on artificial substrates suspended in the pond water, thereby potentially improving the water quality.

     

Cardiac‐specific overexpression of metallothionein attenuates L‐NAME‐induced myocardial contractile anomalies and apoptosis

Hypertension contributes to the high cardiac morbidity and mortality. Although oxidative stress plays an essential role in hypertensive heart diseases, the mechanism remains elusive. Transgenic mice with cardiac overexpression of metallothionein, a heavy metal‐binding scavenger, were challenged with N^G‐nitro‐L‐arginine methyl ester (L‐NAME) for 14 days prior to measurement of myocardial contractile and intracellular Ca²⁺ anomalies as well as cell signalling mechanisms using Western blot and immunofluorescence analysis. L‐NAME challenge elicited hypertension, macrophage infiltration, oxidative stress, inflammation and cardiac dysfunction manifested as increased proinflammatory macrophage marker F4/80, interleukin‐1β (IL‐1β), intracellular production, LV end systolic and diastolic diameters as well as depressed fractional shortening. L‐NAME treatment reduced mitochondrial membrane potential (MMP), impaired cardiomyocyte contractile and intracellular Ca²⁺ properties as evidenced by suppressed peak shortening, maximal velocity of shortening/relengthening, rise in intracellular Ca²⁺, along with elevated baseline and peak intracellular Ca²⁺. These unfavourable mechanical changes and decreased MMP (except blood pressure and macrophage infiltration) were alleviated by overexpression of metallothionein. Furthermore, the apoptosis markers including BAD, Bax, Caspase 9, Caspase 12 and cleaved Caspase 3 were up‐regulated while the anti‐apoptotic marker Bcl‐2 was decreased by L‐NAME treatment. Metallothionein transgene reversed L‐NAME‐induced changes in Bax, Bcl‐2, BAD phosphorylation, Caspase 9, Caspase 12 and cleaved Caspase 3. Our results suggest that metallothionein protects against L‐NAME‐induced myocardial contractile anomalies in part through inhibition of apoptosis.     

Biodegradation kinetics of microcystins-LR crude extract by Lysinibacillus boronitolerans strain CQ5

As the most common variant of microcystins (MCs), microcystin-LR (MCLR) is a kind of toxins produced by some species of harmful cyanobacteria and more and more attention has been paid to it. Biodegradation has been extensively investigated and recognized to be a cost-efficient and environmentally benign method for MC clean-up. In order to further research the growth characteristics of strain and the biodegradation characteristics of MCLR, it is necessary to use the dynamic mathematical models as powerful and useful tools. In this study, strain CQ5 was screened and identified by morphological observation, physiological and biochemical tests, and 16S rDNA sequence analysis. The kinetic models of cell growth and MCLR degradation were established with the Gompertz model and revised Monod kinetic model. The results showed that strain CQ5 had the closest phylogenetic similarity to Lysinibacillus boronitolerans (T-10a, AB199591) in the phylogenetic tree, with 99% bootstrap support. Strain CQ5 could utilize MCLR as the carbon and nitrogen source for growth. When the initial pH value was 7 and the inoculation amount was 3%, strain CQ5 grew well in MSM, in which the MCLR crude extract was used as the carbon and nitrogen source of strain CQ5. Within 244 h, the MCLR concentration changed from 14.12 to 1.57 μg/L and its degradation rate could reach 88.88%. The growth curve fitted with the Gompertz growth model (Nt = 1.3119 * exp(−0.1237 * exp(−6.6341t)), R2 > 0.99). The process of MCLR degradation agreed with the first-order reaction kinetic equation (lnS = 2.64764 − 0.01537t, R2 > 0.99). The linkage relationship between MCLR concentration, cell density, and MCLR degradation rate was consistent with the revised Monod equation (V = 0.342S, R2 > 0.97) at low substrate concentration, where Vmax/ Ks was 0.342. The dynamic relationship in which strain CQ5 degraded MCLR and used it as the carbon and nitrogen source to promote its own growth could be explained by the equation S = 14.12 e− 0.342 Nt (N = 1.08). The growth of strain CQ5 and MCLR concentration in degradation system could be simulated and predicted by the dynamic mathematical models in this study. And the predicted results were very consistent. These results could provide theoretical reference for studying the mechanism of MCLR biodegradation and promote the engineering application of strain CQ5.     

Efficient Plasmonic Au/CdSe Nanodumbbell for Photoelectrochemical Hydrogen Generation beyond Visible Region

In this communication, light harvesting and photoelectrochemical (PEC) hydrogen generation beyond the visible region are realized by an anisotropic plasmonic metal/semiconductor hybrid photocatalyst with precise control of their topology and heterointerface. Controlling the intended configuration of the photocatalytic semiconductor to anisotropic Au nanorods' plasmonic hot spots, through a water phase cation exchange strategy, the site‐selective overgrowth of a CdSe shell evolving from a core/shell to a nanodumbbell is realized successfully. Using this strategy, tip‐preferred efficient photoinduced electron/hole separation and plasmon enhancement can be realized. Thus, the PEC hydrogen generation activity of the Au/CdSe nanodumbbell is 45.29 µmol cm^?2 h^?1 (nearly 4 times than the core/shell structure) beyond vis (λ > 700 nm) illumination and exhibits a high faradic efficiency of 96% and excellent stability with a constant photocurrent for 5 days. Using surface photovoltage microscopy, it is further demonstrated that the efficient plasmonic hot charge spatial separation, which hot electrons can inject into CdSe semiconductors, leads to excellent performance in the Au/CdSe nanodumbbell.     

Quantifying the Volumetric Performance Metrics of Supercapacitors

Nanostructured materials have greatly improved the performance of electrochemical energy storage devices because of the increased activity and surface area. However, nanomaterials (e.g., nanocarbons) normally possess low packing density, and thus occupy more space which restricts their suitability for making electrochemical devices as compact as possible. This has resulted in their low volumetric performance (capacitance, energy density, and power density), which is a practical obstacle for the application of nanomaterials in mobile and on‐board energy storage devices. While rating electrode materials for supercapacitors, their volumetric performance is equally important as the gravimetric metrics and more reliable in particular for systems with limited space. However, the adopted criteria for measuring the volumetric performance of supercapacitors vary in the literature. Identifying the appropriate performance criteria for the volumetric values will set a universal ground for valid comparison. Here, the authors discuss the rationale for quantifying the volumetric performance metrics of supercapacitors from the three progressive levels of materials, electrodes, and devices. It is hoped that these thoughts will be of value for the general community in energy storage research.