Manganese Monoxide/Biomass-Inherited Porous Carbon Nanostructure Composite Based on the High Water-Absorbent Agaric for Asymmetric Supercapacitor

Biomass-inherited metal oxide/carbon composites have been utilized as competitive materials of supercapacitor electrodes owing to the hierarchical structures, fast regeneration rate, and easy synthesis. However, the low content and agglomeration of metal oxides are the contradictory issues to be addressed for their practical applications. In this work, manganese monoxide/biomass-inherited porous carbon (MnO/BPC) nanostructure composites with high MnO content (∼75%) and uniform distribution have been prepared through a simple immersion-calcination process by high water-absorbent agaric. The superhigh Mn2+ solution absorption of agaric ensures the high MnO content in MnO/BPC composite, and the abundant internal chitin with hydrogel and hot-melting property enables the uniform dispersion of MnO in carbon matrix. The carbon nanostructure endows the composite with high specific surface area, efficient electron/ion transportation, and better electrolyte wettability. As expected, the MnO/BPC composite materials realizes high capacitance of ∼735 mF cm–2 (∼637 F g–1) at 3 mA cm–2, good rate performance (∼608 mF cm–2 at 10 mA cm–2), and excellent cycling performance (capacity retention of ∼91% at 10 mA cm–2, 5000 cycles). In addition, this work presents a facile and productive strategy to obtain metal-based composites with high metal-oxide content and homogeneous distribution by adopting the edible and worldwide abundant agaric

Defect-Rich W/Mo-Doped V₂O₅ Microspheres as a Catalytic Host To Boost Sulfur Redox Kinetics for Lithium–Sulfur Batteries

It is very important to develop ideal electrocatalysts to accelerate the sulfur redox kinetics in both the discharging and charging processes for high-performance lithium–sulfur batteries. Herein, defect-rich cation-doped V2O5 yolk–shell microspheres are reported as a catalytic host of sulfur. The doping of W or Mo cations induces no impurities, broadens the lattice spacing of V2O5, and enriches the oxygen vacancy defects. Thus, the doped V2O5 host affords sufficient active sites for chemically anchoring polysulfides and promising catalytic effect on the mutual conversion between different sulfur intermediates. As a result, the S/W–V2O5 cathode delivers a discharging capacity of 1143.3 mA g–1 at an initial rate of 0.3 C and 681.8 mA g–1 at 5 C. Even under a sulfur loading of up to 5.5 mg cm–2 and a minimal electrolyte/sulfur ratio of 6 μL mg–1, the S/W–V2O5 cathode could still achieve good sulfur utilization and dependable cycle stability. Thus, this work offers an electrocatalytic host based on the cation doping strategy to greatly enhance the sulfur redox kinetics for high-performance Li–S batteries

Two for One: A Biomass Strategy for Simultaneous Synthesis of MnO₂ Microcubes and Porous Carbon Microcubes for High Performance Asymmetric Supercapacitors

The capacitive properties of asymmetric supercapacitors (ASCs) are inseparable from the development of anode and cathode materials, which usually require high accessible surface area and uniform porous distribution. Herein, a simple and economical “two for one” strategy is introduced for the simultaneous synthesis of microscale porous MnO2 microcubes (PMMs) and porous carbon microcubes (PCMs) derived from a single precursor cubic MnCO3/biocarbon (CM) which are prepared by natural agaric. Benefiting from a high specific surface area, delicate construction, and adequate mesoporous distribution, PCMs and PMMs could help to realize fast ion diffusion and easy ion accessibility. As expected, microscale PCM anode and PMM cathode materials exhibit superior capacitive performances, including high specific capacitance and impressive rate performance in a three-electrode system, respectively. Moreover, the assembled ASCs physical device PCM//PMM presents a high energy density (46.1 Wh kg–1 at 1.0 kW kg–1) and an excellent long-term cyclability (91% capacitance retention after 10 000 cycles at 1.0 A g–1). Therefore, the two-for-one strategy not only provided a simple and effective method to prepare high-performance electrode materials for ASCs, but also it is of great significance for natural biomass to achieve multidirectional applications and effectively replace commercial carbon sources from fossil fuels

N‑Doped Carbon Fiber-Encapsulated CoS₂/SnS₂ Heterostructures Facilitate Polysulfide Conversion for Lithium–Sulfur Batteries

Heterojunction structures as an advanced strategy may promote the synergistic effect of different component materials; the rational design of heterojunctions allows them to exhibit various advantages when applied to lithium–sulfur batteries. Hollow CoSn(OH)6 was used as a precursor, and polyacrylonitrile PAN and sulfur powder were used as raw materials. N-doped carbon nanofiber-encapsulated CoS2/SnS2 heterostructured materials CoS2/SnS2@CNFs were prepared by an electrostatic spinning technique and in situ vulcanization and applied to the lithium–sulfur battery cathode. A hollow cubic material with structural stability and a physical domain-limiting effect, that is, the CoS2/SnS2 heterostructure, was effectively constructed, and rapid charge transfer was realized by a built-in electric field induced to form by the heterogeneous interface. Meanwhile, the fiber-like network structure facilitates the wetting of the electrolyte and shortens the ion transfer path. The results show that a CoS2/SnS2@CNFs@S-based battery exhibits an excellent electrochemical performance. The initial discharge specific capacities were 1204.3 mAh g–1 at a current density of 0.1 C and 615.2 mAh g–1 at 4 C. The long-cycle performance showed that the cells only exhibited an ultralow decay rate of 0.067% per week on average after 1000 cycles at 2C. When the sulfur loading was increased to 5.3 mg cm–2 and the electrolyte/sulfur ratio was 6 μL mg–1, excellent cycling stability was still demonstrated after 250 weeks of cycling at 0.2C

WS₂‑TiO₂ Heterostructure Catalyst for Boosting the Polysulfide Adsorption–Conversion in Lithium–Sulfur Batteries

The introduction of suitable catalytic hosts is considered as a suitable way to hinder the “shuttling effect” of lithium polysulfides (LPSs) in lithium–sulfur (Li–S) batteries. At present, most catalytic hosts can accelerate the conversion of LPSs, but there are few reports that catalytic hosts accelerate the conversion of solid-phase discharge products (Li2S2/Li2S) into liquid-phase LPSs. Herein, a heterostructure catalyst with flaky WS2-modified TiO2 hollow spheres (WS2-TiO2) is reported, which accelerates the conversion between liquid-phase LPSs and solid-phase Li2S2/Li2S. A Li–S battery with S@WS2-TiO2 cathode exhibits an initial discharge specific capacity of 1091.7 mAh g–1 at 0.3C, outstanding rate capability of 378.7mAh g–1 at 10C, and low capacity decay of 0.0753% per cycle over 800 cycles at 1C. Therefore, this work provides a suitable way to construct heterosturcture catalytic hosts to realize the commercial application of Li–S batteries

High-Performance Cross-Linked Particle-Like LaNiO₃ As a Multifunctional Separator to Significantly Enhance the Redox Kinetics of Lithium–Sulfur Batteries

The “shuttle effect” and slow conversion kinetics of lithium polysulfide severely hinder the practical application of lithium–sulfur (Li–S) batteries. A perovskite functional separator (LaNiO3@PP) was introduced into lithium–sulfur batteries for applications; the lanthanum and nickel elements on the A-site and B-site have been proved to have good adsorption and catalytic effects on LiPSs in previous studies, and constructing the material with such dual active sites can greatly enhance its adsorption capacity for LiPSs. LaNiO3 prepared by the sol–gel method has the characteristics of low raw material cost and a simple synthesis method, which is an important prerequisite for product commercialization. It is found that the impedance of LaNiO3@PP batteries is low, which is favorable for the kinetic process of the batteries. According to the self-discharge experiment, it can be proved that LaNiO3@PP has a good ability to suppress self-discharge, and the capacity loss is only 8.76% after 7 days of resting, because LaNiO3 converts polysulfide to sulfate and the sulfate intermediate to Li2S through further electrochemical reaction during the discharge process, which effectively suppresses the shuttle effect and reduces the loss of active material for LaNiO3@PP with significantly high specific capacity and rate capability as well as stable long-cycle performance. For an area loading of 1.106 mg cm–2, the initial specific capacity at 0.1C is 1320.28 mAh g–1, and the discharge specific capacity of 591.40 mAh g–1 can still be maintained after 300 long cycles at 0.5C. When the area loading reached 4.926 mg cm–2 and the electrolyte-to-activator ratio (E/S) was 8.1 μL mg–1, and the initial capacity at 0.2C was 665.49 mAh g–1, the good electrochemical performance was maintained after 50 cycles. This work provides a new strategy for the preparation of high performance and high stability Li–S battery separator

DataSheet1_Sedimentary Rock Magnetic Response to Holocene Environmental Instability in the Pearl River Delta.docx

Located on the northern coast of the South China Sea, the densely populated Pearl River Delta has experienced the combined effects of sea-level change, monsoon-driven discharge, and especially human activity, since the late Holocene. However, how these factors have regulated the regional environmental and sedimentary evolution remains unclear. To better understand these processes, we conducted a high-resolution rock magnetic investigation of the Holocene sediments of core DS01, drilled in the vicinity of the West River channel in the head area of the Pearl River deltaic plain. The magnetic grain-size proxy of the ARM/κlf ratio (the ratio of anhysteretic remanent magnetization to low-field magnetic susceptibility) indicates a long-term fining trend of the magnetite grain size, which may be a response to an increase in the weathering intensity in the Asian monsoon region during the Holocene. An interval with an enhanced concentration of magnetic minerals (mainly magnetite and hematite) occurred during 7.7–4.8 kyr BP (calendar years before 1950), coinciding with a period of delta progradation. During the marine transgression in the early Holocene, two similar intervals of magnetic enrichment may reflect regional hydrodynamic shifts associated with cooling events at ∼9.5–9.3 kyr BP and 8.2 kyr BP. The subsequent 4.2 kyr BP cooling event possibly induced a cold and dry environment in the sediment source area. From ∼800 yr BP onward, there was a major increase in the sedimentary magnetic mineral content, likely in response to intensified agricultural and industrial activities.</p

MOF-Encapsulating Metal–Acid Interfaces for Efficient Catalytic Hydrogenolysis of Biomass-Derived Aromatic Aldehydes

Developing an efficient and selective catalyst for C–O hydrogenolysis of biomass-derived aromatic aldehydes, such as 5-methylfurfural (MF), 5-hydroxymethylfurfural (HMF), and vanillin (VA), is highly significant for the synthesis of biofuel and fine chemicals. Herein, metal–organic framework (MOF)-encapsulating metal–acid interfaces (Pd@UiO–CH2SO3H, Pd@UiO–PhSO3H) were first reported. Compared with traditionally supported catalysts (Pd/UiO–SO3H, Pd/UiO–NH2), Pd–acid-interface-encapsulated MOFs show much higher activity and selectivity for MF to 2,5-dimethylfuran (DMF), HMF to DMF, and VA to 2-methoxy-4-methylphenol (MMP) reactions. In particular, Pd@UiO–SO3H shows the best catalytic performance with 89.0 and 86.0% DMF yield from MF and HMF and a 99.4% MMP yield from VA based on its suitable hydrophilicity, high hydrogen activation ability, and abundant Pd–SO3H interface active sites. According to the catalytic performance of Pd/UiO–NH2 and the results of an ATR-IR test, the acidic sites on the Pd–acid interface can accelerate the activation of the hydroxyl group for these hydrogenolysis reactions. This work provides an effective design strategy for the preparation of MOF-encapsulating metal–acid interfaces and shows the powerful synergistic effect of hydrogenation and acid catalysis

Dual-Function Perovskite Catalytic Layer for High-Performance Lithium Sulfur Batteries

In order to solve the shuttle effect problem of energy storage devices, especially lithium–sulfur batteries, and achieve the goal of producing safe, reliable, and excellent lithium–sulfur batteries, this study uses lanthanide perovskite materials (LaCoO3) to modify the surface of sulfur electrodes and form an isolated catalytic layer. Through the coordination of chemisorption and catalytic conversion, lithium–sulfur batteries with a dual-function catalytic layer show excellent electrochemical capabilities, including high reversible capacity, excellent rate capacity, good cycle stability, and a long cycle life

<b>New </b>^{<strong>40</strong>}<b>Ar/</b>^{<strong>39</strong>}<b>Ar dating and paleomagnetism of the Pana Formation rocks from the Linzhou basin, Lhasa Block: implications for the India-Asia collision</b>

Our paleomagnetic and 40Ar/39Ar geochronologic investigation herein indicates a paleolatitude of ~31°N for the LB around ~53 Ma. Combined with the revised Late Cretaceous paleolatitude estimates, the LB was inferred at a paleolatitude of ~24°N in the Late Cretaceous and then reached a present-like location at ca. 53 Ma. Incorporating a reasonable estimate (~1000 km) for the northward extension of the Greater India, our paleomagnetic reconstruction of the Neo-Tethyan tectonic realm strongly supports a two-stage collision scenario consisting of the ~55 Ma Arc-India collision followed by the final collision between the India-Arc assemblage and Asia at ~36-31 Ma.</p