Interconnected Nanoflake Network Derived from a Natural Resource for High-Performance Lithium-Ion Batteries

Numerous natural resources have a highly interconnected network with developed porous structure, so enabling directional and fast matrix transport. Such structures are appealing for the design of efficient anode materials for lithium-ion batteries, although they can be challenging to prepare. Inspired by nature, a novel synthesis route from biomass is proposed by using readily available auricularia as retractable support and carbon coating precursor to soak up metal salt solution. Using the swelling properties of the auricularia with the complexation of metal ions, a nitrogen-containing MnO@C nanoflake network has been easily synthesized with fast electrochemical reaction dynamics and a superior lithium storage performance. A subsequent carbonization results in the in situ synthesis of MnO nanoparticles throughout the porous carbon flake network. When evaluated as an anode material for lithium-ion batteries, an excellent reversible capacity is achieved of 868 mA h g^–1 at 0.2 A g^–1 over 300 cycles and 668 mA h g^–1 at 1 A g^–1 over 500 cycles, indicating a high tolerance to the volume expansion. The approach investigated opens up new avenues for the design of high performance electrodes with highly cross-linked nanoflake structures, which may have great application prospects

Using Asphaltene Supermolecules Derived from Coal for the Preparation of Efficient Carbon Electrodes for Supercapacitors

Asphaltene supermolecules extracted from coal consist of highly condensed polyaromatic units and peripheral aliphatic chains, which is a natural source with high carbon content. In this study, we demonstrate that the asphaltene can be used as an ideal supermolecular carbon precursor for the fabrication of carbon nanosheets by self-assembly via π–π and hydrogen bonding interactions with a sheet-structure-directing agent of graphene oxide. The overall thickness of the obtained asphaltene based carbon nanosheets can be tuned from 13 ± 3 to 41 ± 5 nm. These carbon nanosheets show an electrical conductivity of ca. 450 S m^–1. When they are used as electrode materials for supercapacitors, the carbon nanosheets demonstrate a specific capacitance of 163 F g^–1 even at a current density of 30 A g^–1 tested in a three-electrode system, due to high electrically conductive networks and short diffusive paths. The maximum specific gravimetric capacitance and surface area-normalized capacitance in two-electrode system are 191 F g^–1 and 43 μF cm^–2, respectively, indicating very high utilization of the available surface area. These results prove that asphaltene is a promising molecular precursor for the preparation of energy materials, further displaying an efficient route for staged conversion of coal that is abundant in nature

Incorporating Sulfur Inside the Pores of Carbons for Advanced Lithium–Sulfur Batteries: An Electrolysis Approach

We have developed an electrolysis approach that allows effective and uniform incorporation of sulfur inside the micropores of carbon nanosheets for advanced lithium–sulfur batteries. The sulfur–carbon hybrid can be prepared with a 70 wt % sulfur loading, in which no nonconductive sulfur agglomerations are formed. Because the incorporated sulfur is electrically connected to the carbon matrix in nature, the hybrid cathode shows excellent electrochemical performance, including a high reversible capacity, good rate capability, and good cycling stability, as compared to one prepared using the popular melt-diffusion method

Enhancing Ethanol Coupling to Produce Higher Alcohols by Tuning H₂ Partial Pressure over a Copper-Hydroxyapatite Catalyst

Catalytic upgrading of ethanol, as a platform molecule from biomass to higher alcohols (C4–12), is a low-carbon route for value-added chemical production. However, the products are generally obtained in low selectivity due to the uncontrollable reactivity of intermediates that cause a complex reaction network. In this study, we show that unsaturated intermediates of aldehydes can be rapidly hydrogenated by surface hydrogen species during the ethanol upgrading process, thereby greatly inhibiting the cyclization reaction of aldehydes. Specifically, the product distributions on the Cu-hydroxyapatite (Cu-HAP) catalyst shift stepwise to higher alcohols from aromatic oxygenates with the partial pressure of hydrogen increasing from 0 to 95 kPa. Kinetic measurements and in situ ethanol infrared results indicated that the intermediates during this process are acetaldehyde and 2-butenal. Combined with physical structure and chemical state analysis of the catalyst, we found that Cu sites catalyze the hydrogenation of the CC bond of 2-butenal under a hydrogen atmosphere. The C–C coupling of ethanol to higher alcohols over Cu-HAP follows the Guerbet mechanism. In comparison, on bare HAP, n-butanol is formed as a primary product even though little amount of acetaldehyde was detected, indicating that ethanol proceeds mainly in a direct coupling process to yield higher alcohols. This study introduces an efficient ethanol valorization approach that is enabled by subtle control of the intermediate conversion over the Cu-HAP catalyst by the hydrogen partial pressure

Additional file 1 of Added value of CE-CT radiomics to predict high Ki-67 expression in hepatocellular carcinoma

Additional file 1: Supplement Figure 1. CE-CT imaging features of HCC. A, non-rim APHE; B, non-peripheral washout and enhancing complete capsule; C, corona enhancement; D, nodule-in-nodule architecture; E, mosaic architecture; F, scar sign; G, tumor rupture; H, PVTT; I, peritumoral satellite. Supplement Table 1. Cohen’s kappa value of CT imaging features. Supplement Figure 2. The names and weights of radiomics features associated with the Ki-67 expression in training se

Diaminohexane-Assisted Preparation of Coral-like, Poly(benzoxazine)-Based Porous Carbons for Electrochemical Energy Storage

The assembly of commercial silica colloids in the presence of 1,6-diaminohexane and their subsequent encapsulation by poly­(benzoxazine) have been used to produce coral-like porous carbons. The pyrolysis of the polymer followed by the removal of the silica produces a carbon with a continuous skeleton that contains spherical medium-size pores as “reservoirs” with a structure similar to a bunch of grapes. The total volume and the diameter of the “reservoir” pores are tunable. The coral-like morphology and the pore structure of the carbons make them suitable for use as electrode materials for supercapacitors and lithium-ion batteries. As supercapacitor electrodes, they exhibit excellent long-term cycle stability (almost no capacitance fading after 20 000 cycles at a current density of 1 A g^–1) and good rate capability with capacitance retention of 88% (from 0.1 A g^–1 to 5 A g^–1). Meanwhile, as a matrix for the encapsulation of SnO₂ nanoparticles for Li-ion storage, the electrodes also show a high specific capacity and good cycling stability, i.e., 900 mA h g^–1 after 50 charge–discharge cycles. The good electrochemical performance of such carbons shows that they are promising candidate electrode materials for electrochemical energy storage

Thin Porous Alumina Sheets as Supports for Stabilizing Gold Nanoparticles

Thin porous alumina sheets have been synthesized using a lysine-assisted hydrothermal approach resulting in an extraordinary catalyst support that can stabilize Au nanoparticles at annealing temperatures up to 900 °C. Remarkably, the unique architecture of such an alumina with thin sheets (average thickness ∼15 nm and length 680 nm) and rough surface is beneficial to prevent gold nanoparticles from sintering. HRTEM observations clearly showed that the epitaxial growth between Au nanoparticles and alumina support was due to strong interfacial interactions, further explaining the high sinter-stability of the obtained Au/Al₂O₃ catalyst. Consequently, despite calcination at 700 °C, the catalyst maintains its gold nanoparticles of size predominantly 2 ± 0.8 nm. Surprisingly, catalyst annealed at 900 °C retained the highly dispersed small gold nanoparticles. It was also observed that a few gold particles (6–25 nm) were encapsulated by an alumina layer (thickness less than 1 nm) to minimize the surface energy, revealing a surface restructuring of the gold/support interface. As a typical and size-dependent reaction, CO oxidation is used to evaluate the performance of Au/Al₂O₃ catalysts. The results obtained demonstrated Au/Al₂O₃ catalyst calcined at 700 °C exhibited excellent activity with a complete CO conversion at ∼30 °C (<i>T</i>_100% = 30 °C), and even after calcination at 900 °C, the catalyst still achieved its <i>T</i>_50% at 158 °C. In sharp contrast, Au catalyst prepared using conventional alumina support shows almost no activity under the same preparation and catalytic test conditions

Monolithic Carbons with Tailored Crystallinity and Porous Structure as Lithium-Ion Anodes for Fundamental Understanding Their Rate Performance and Cycle Stability

A series of hierarchically multimodal (micro-, meso-/macro-) porous carbon monoliths with tunable crystallinity and architecture have been designedly prepared through a simple and effective gelation through a dual phase separation process and subsequent pyrolysis. Because of the magnificent structural characteristics, such as highly interconnected three-dimensional (3D) crystalline carbon framework with hierarchical pore channels, which ensure a fast electron transfer network and lithium-ion transport, the carbon anodes exhibit a good cycle performance and rate capability in lithium-ion cells. Importantly, a correlation between the electrochemical performances and their structural features of crystalline and textural parameters has been established for the first time, which may be of valid for better understanding of their rate performance and cycle stability