Terpenoids from the Soft Coral Stereonephthya bellissima.

A detailed chemical study of the extract from the soft coral Stereonephthya bellissima resulted in the isolation and identification of seven new sesquiterpenoids, bellissinanes A-G (1-7), along with four new diterpenes (8-11). Bellissinane A (1) is the third reported nardosinane-type sesquiterpene bearing a 6/5/6 tricyclic system. Bellissinanes C and D (3, 4) contain a phenylethylamine fragment, which is relatively unusual in marine organisms. Bellissinanes E-G (5-7) belong to the rare class of nornardosinane sesquiterpenoids. Structurally uncommon octahydro-1H-indenyl-type and prenyleudesmane-type skeletons were characterized for herpetopanone B (8) and bellissimain A (9), respectively. Bellissinane E (5) exhibited in vivo angiogenesis-promoting activity.

Elaborating the Crystal Water of Prussian Blue for Outstanding Performance of Sodium Ion Batteries.

Prussian blue (PB) is one of the main cathode materials with industrial prospects for the sodium ion battery. The structural stability of PB materials is directly associated with the presence of crystal water within the open 3D framework. However, there remains a lack of consensus regarding whether all forms of crystal water have detrimental effects on the structural stability of the PB materials. Currently, it is widely accepted that interstitial water is the stability troublemaker, whereas the role of coordination water remains elusive. In this work, the dynamic evolution of PB structures is investigated during the crystal water (in all forms) removal process through a variety of online monitoring techniques. It can be inferred that the PB-130 °C retains trace coordination water (1.3%) and original structural integrity, whereas PB-180 °C eliminates almost all of crystal water (∼12.1%, including both interstitial and coordinated water), but inevitably suffers from structural collapse. This is mainly because the coordinated water within the PB material plays a crucial role in maintaining structural stability via forming the -N≡C-FeLS-C≡N- conjugate bridge. Consequently, PB-130 °C with trace coordination water delivers superior reversible capacity (113.6 mAh g-1), high rate capability (charge to >80% capacity in 3 min), and long cycling stability (only 0.012% fading per cycle), demonstrating its promising prospect in practical applications.

Pseudoceranoids A-J, Sesquiterpene-Based Meroterpenoids with Cytotoxicity from the Sponge Pseudoceratina purpurea.

Pseudoceranoid A (1), a rare merosesquiterpene featuring a rearranged 4,9-friedodrimane-type core with a crotonolactone moiety, two new rearranged 4,9-friedodrimane-type sesquiterpene cyclopentanones (2 and 3), and three new rearranged 4,9-friedodrimane-type sesquiterpene hydroquinones (4-6), along with two new drimane-type sesquiterpene derivatives (7 and 8), as well as two new 4,9-friedodrimane-type sesquiterpene quinones (9 and 10), were isolated from the South China Sea sponge Pseudoceratina purpurea. The structures of compounds were established by analysis of spectroscopic data, as well as by single-crystal X-ray diffraction, DP4+ probability analyses, and calculated electronic circular dichroism. Compound 4 showed weak cytotoxicity against K562, H69AR, and MDAMB-231 cell lines with IC50 values of 3.01, 7.74, and 9.82 µM, respectively. Compound 5 exhibited cytotoxicity against the H69AR cell line with an IC50 value of 2.85 µM.

Embedding oxophilic rare-earth single atom in platinum nanoclusters for efficient hydrogen electro-oxidation.

Designing Pt-based electrocatalysts with high catalytic activity and CO tolerance is challenging but extremely desirable for alkaline hydrogen oxidation reaction. Herein we report the design of a series of single-atom lanthanide (La, Ce, Pr, Nd, and Lu)-embedded ultrasmall Pt nanoclusters for efficient alkaline hydrogen electro-oxidation catalysis based on vapor filling and spatially confined reduction/growth of metal species. Mechanism studies reveal that oxophilic single-atom lanthanide species in Pt nanoclusters can serve as the Lewis acid site for selective OH- adsorption and regulate the binding strength of intermediates on Pt sites, which promotes the kinetics of hydrogen oxidation and CO oxidation by accelerating the combination of OH- and *H/*CO in kinetics and thermodynamics, endowing the electrocatalyst with up to 14.3-times higher mass activity than commercial Pt/C and enhanced CO tolerance. This work may shed light on the design of metal nanocluster-based electrocatalysts for energy conversion.

A Static Tin-Manganese Battery with 30000-Cycle Lifespan Based on Stabilized Mn3+/Mn2+ Redox Chemistry.

High-potential Mn3+/Mn2+ redox couple (>1.3 V vs SHE) in a static battery system is rarely reported due to the shuttle and disproportionation of Mn3+ in aqueous solutions. Herein, based on reversible stripping/plating of the Sn anode and stabilized Mn2+/Mn3+ redox couple in the cathode, an aqueous Sn-Mn full battery is established in acidic electrolytes. Sn anode exhibits high deposition efficiency, low polarization, and excellent stability in acidic electrolytes. With the help of H+ and a complexing agent, a reversible conversion between Mn2+ and Mn3+ ions takes place on the graphite surface. Pyrophosphate ligand is initially employed to form a protective layer through a complexation process with Sn4+ on the electrode surface, effectively preventing Mn3+ from disproportionation and hindering the uncontrollable diffusion of Mn3+ to electrolytes. Benefiting from the rational design, the full battery delivers satisfied electrochemical performance including a large capacity (0.45 mAh cm-2 at 5 mA cm-2), high discharge plateau voltage (>1.6 V), excellent rate capability (58% retention from 5 to 30 mA cm-2), and superior cycling stability (no decay after 30 000 cycles). The battery design strategy realizes a robustly stable Mn3+/Mn2+ redox reaction, which broadens research into ultrafast acidic battery systems.

N-doped engineering of a high-voltage LiNi0.5Mn1.5O4 cathode with superior cycling capability for wide temperature lithium-ion batteries.

Spinel LiNi0.5Mn1.5O4 (LNMO) is one potential cathode candidate for next-generation high energy-density lithium-ion batteries (LIBs). However, serious capacity decay from its poor structural stability, especially at high operating temperatures, shadows its application prospects. In this work, N-doped LNMO (LNMON) was synthesized by a facile co-precipitation method and multistep calcination, exhibiting a unique yolk-shell architecture. Concurrently, N dopants are introduced into a LNMO lattice, endowing LNMON with a more stable structure via stronger Ni-N/Mn-N bindings. Benefiting from the synergistic effect of the yolk-shell structure and N-doped engineering, the obtained LNMON cathode exhibits an impressive rate and the state-of-the-art cycling capability, delivering a high capacity of 103 mA h g-1 at 25 °C after 8000 cycles. Even at a high operating temperature of 60 °C, the capacity retention remains at 92% after 1000 cycles. The discovery of N dopants in improving the cycling capability of LNMO in our case offers a prospective approach to enable 5 V LNMO cathode materials with excellent cycling capability.

Polycyclic Aromatic Hydrocarbons as a New Class of Promising Cathode Materials for Aluminum-Ion Batteries.

As an emerging post-lithium battery technology, aluminum ion batteries (AIBs) have the advantages of large Al reserves and high safety, and have great potential to be applied to power grid energy storage. But current graphite cathode materials are limited in charge storage capacity due to the formation of stage-4 graphite-intercalated compounds (GICs) in the fully charged state. Herein, we propose a new type of cathode materials for AIBs, namely polycyclic aromatic hydrocarbons (PAHs), which resemble graphite in terms of the large conjugated π bond, but do not form GICs in the charge process. Quantum chemistry calculations show that PAHs can bind AlCl4 - through the interaction between the conjugated π bond in the PAHs and AlCl4 - , forming on-plane interactions. The theoretical specific capacity of PAHs is negatively correlated with the number of benzene rings in the PAHs. Then, under the guidance of theoretical calculations, anthracene, a three-ring PAH, was evaluated as a cathode material for AIBs. Electrochemical measurements show that anthracene has a high specific capacity of 157 mAh g-1 (at 100 mA g-1 ) and still maintains a specific capacity of 130 mAh g-1 after 800 cycles. This work provides a feasible "theory guides practice" research model for the development of energy storage materials, and also provides a new class of promising cathode materials for AIBs.

Factors Affecting College Students' Continuous Intention to Use Online Course Platform.

In recent years, online learning model has become the mainstream in higher education. The cooperation between universities and Internet education platforms provides a good learning environment and abundant online elective courses for college students, but the practical teaching effect is not ideal. Therefore, based on the Universal Theory of Acceptance and Use of Technology (UTAUT), this study introduced the perceived cost and content quality to build a model of college students' continuous intention to use online course platforms, and used structural equation model to study the relationship among the variables. The results showed that effort expectancy and social influence affected continuous intention indirectly via performance expectancy; content quality indirectly affected continuous intention through effort expectancy, performance expectancy and effort expectancy-performance expectancy; perceived cost had a significant negative effect on continuous intention. These research results provide new ideas for the design and development of online course platform.

Template-assisted loading of Fe3O4 nanoparticles inside hollow carbon "rooms" to achieve high volumetric lithium storage.

The design of electrodes with simultaneously high compaction density, developed porosity, and structural stability has always been a challenge so as to meet the demand of high volumetric performance lithium ion storage devices. In this paper, we demonstrate a new compositing method for hollow carbon "room" loading of Fe3O4 nanoparticles (HCR@Fe3O4) with the assistance of Na2CO3 salt crystal templates. The as-obtained HCR@Fe3O4 composites have a massive compaction density (1.79 g cm-3), abundant multimodal pores (1.26 cm3 g-1), and a large content of Fe3O4 (64.2 wt%), which leads to excellent volumetric capacitive performance. More importantly, the unique compositing model not only provides a fast transmission channel for Li+ but also alleviates the mechanical strain efficiently through the cavity between the Fe3O4 nanoparticles and the carbon wall. When evaluated as an anode of lithium ion batteries, the resultant HCR@Fe3O4 electrode exhibits a remarkable volumetric capacity of 2044 mA h cm-3 at 0.2 A g-1 and a stable cycle life of 828 mA h cm-3 after 1000 cycles at 5 A g-1. The assembled HCR@Fe3O4//AC lithium ion hybrid capacitor device exhibits a high energy density of 173 W h L-1 at a power density of 190 W L-1, demonstrating its high-level integrated volumetric density/power density.

Rigid-Flexible Coupling Carbon Skeleton and Potassium-Carbonate-Dominated Solid Electrolyte Interface Achieving Superior Potassium-Ion Storage.

Potassium-ion energy-storage devices are highly attractive in the large-scale energy storage field, but the intercalation of large K ions greatly worsens the stability of electrode structures and solid electrolyte interphase (SEI) films, causing slow reaction dynamics and poor durability. In this Article, inspired by bubble wraps in our life, a bubble-wrap-like carbon sheet (BPCS) with a rigid-flexible coupling porous architecture is fabricated on the microscale, exhibiting strong structural stability and good accommodation for volume expansion. In the meantime, a K2CO3·1.5H2O-dominated SEI is created by an interfacial transfer behavior of carbonate groups. These K2CO3·1.5H2O nanograins not only enhance the stability of the SEI by constructing a stable scaffold but also create more diffusion routes for K ions. On the basis of the above, using the BPCS as the anode of potassium-ion batteries delivers reversible capacities of 463 mAh g-1 at 50 mA g-1 and 195 mAh g-1 at 10 A g-1 with a long cycling life. The assembled BPCS//NPC potassium-ion hybrid capacitor exhibits a high energy density of 167 Wh kg-1 and a superior cycling capability with 80.8% capacity retention over 10 000 cycles with nearly 100% Coulombic efficiency. Even at the higher current density of 10 A g-1, the device could deliver an energy density of 92.9 Wh kg-1 over 5000 cycles at a power density of 9200 W kg-1 with only 0.002% fading per cycle, which can rival lithium-ion hybrid supercapacitors.

Bio-derived yellow porous TiO2: the lithiation induced activation of an oxygen-vacancy dominated TiO2 lattice evoking a large boost in lithium storage performance.

Oxygen deficient TiO2 has attracted extensive attention owning to its narrow bandgap and high electrical conductivity. In this work, novel yellow TiO2 with hierarchically porous architecture is fabricated by a facile pyrolysis method in air via a biomass template. The obtained yellow TiO2 exhibits interesting lithiation induced activation during cycling, which gives rise to a phase change from poorly crystallized TiO2 to an amorphous phase, accompanied by a colour change from yellow to black. In contrast to the intercalation mechanism reported in most of the literature on the TiO2 anode of LIBs, notably, the reversible redox reaction between Ti3+ and metal Ti can be verified in this case, demonstrating the novel conversion reaction mechanism of the TiO2 electrode. Based on this, the yellow porous TiO2 delivers enhanced electrochemical performance as an anode for LIBs with a superior capacity of 480 mA h g-1 at 5 A g-1 and a high capacity of 206 mA h g-1 at 10 A g-1 after 8000 cycles.

Cable-like heterogeneous porous carbon fibers with ultrahigh-rate capability and long cycle life for fast charging lithium-ion storage devices.

In this paper, we propose a space-confined foaming approach to fabricate cable-like heterogeneous porous carbon fibers (Si-CPCFs) containing an inner graphitized carbon "conductor" and an outer Si-doping amorphous carbon "shield". Benefiting from the fast Li+ intercalation and high conductivity of the "inner conductor", and the rich pseudocapacitance of the "outer shield", the Si-CPCFs exhibit an ultrahigh-rate capability and cycling performance, leading to a high capacity of 132 mA h g-1 even at an ultra-high current density of 100 A g-1 after 10 000 cycles. The assembled lithium ion hybrid supercapacitors (LIHCs) also deliver a superior energy density of 50 W h kg-1 at an ultra-high power density of 113 kW kg-1, really achieving both a high energy density and power density of LIHCs. The success of the cable-like heterogeneous porous carbon architecture proposes a new direction to circumvent the discrepancy in kinetics and capacity mismatch, and also attracts more attention to heterogeneous nanostructures with multiple functions.

Bioinspired Mineralization under Freezing Conditions: An Approach to Fabricate Porous Carbons with Complicated Architecture and Superior K+ Storage Performance.

Bioinspired mineralization is a powerful method for designing and preparing nanomaterials. In this work, we developed a bioinspired mineralization approach under freezing conditions and fabricated methyl cellulose (MC)/NaHCO3 flake precursors with a sophisticated hierarchical structure. Based on this, amazing wing-like porous carbon sheets (WPCSs) assembled by numerous interconnected hollow carbon bubbles were obtained after carbonization and removal of inorganic crystals, which are seldom obtained by other artificial methods. Benefiting from their open framework, large surface area, and enlarged interlayer spacing of graphitized nanocrystallites, the obtained WPCSs exhibited an obvious boost in potassium storage performance. As an anode of potassium-ion batteries, they showed high reversible capacities of 347 mAh g-1 at 50 mA g-1 and 122 mAh g-1 at 20 A g-1 and relatively stable cyclability for 3000 cycles. The assembled WPCS//WPCS potassium-ion hybrid supercapacitor delivered a high energy density of 108 Wh kg-1 at a power density of 280 W kg-1. Given the cost effectiveness and green process, the modified bioinspired mineralization under freezing conditions would provide a facile and green way for exploring porous carbons with controlled structures and rich multifunction.

Marine-Biomass-Derived Porous Carbon Sheets with a Tunable N-Doping Content for Superior Sodium-Ion Storage.

Synthesis of the electrode materials of sodium-ion storage devices from sustainable precursors via green methods is highly desirable. In this work, we fabricated a unique N, O dual-doped biocarbon nanosheet with hierarchical porosity by direct pyrolysis of low-cost cuttlebones and simple air oxidation activation (AOA) technique. With prolonging AOA time, thickness of the carbon sheets could be reduced controllably (from 35 to 5 nm), which may lead to tunable preparation of carbon nanosheets with a certain thickness. Besides, an unexpected increase in N-doping amount from 7.5 to 13.9 atom % was observed after AOA, demonstrating the unique role of AOA in tuning the doped heteroatoms of carbon matrix. This was also the first example of increasing N-doping content in carbons by treatment in air. More importantly, by optimizing the thickness of carbon sheets and heteroatom doping via AOA, superior sodium capacity-cycling retention-rate capability combinations were achieved. Specifically, a current state-of-the-art Na+ storage capacity of 640 mAh g-1 was obtained, which was comparable with the lithium-ion storage in carbon materials. Even after charging/discharging at large current densities (2 and 10 A g-1) for 10 000 cycles, the as-obtained samples still retained the capacities of 270 and 138 mAh g-1, respectively, with more than 90% retention. The assembled sodium-ion capacitors also delivered a high integrated energy-power density (36 kW h kg-1 at an ultrahigh power density of 53 000 W kg-1) and good cycling stability (90.5% of capacitance retention after 8000 cycles at 5 A g-1).