Heteroaromatic‐conjugated aromatic molecules have inspired numerous interests in rechargeable batteries like Li‐ion batteries, but were limited by low conductivity and easy dissolution in ...electrolytes. Herein, we immobilize a nitrogen‐rich aromatic molecule tricycloquinazoline (TQ) and CuO4 unit into a two‐dimensional (2D) conductive metal–organic framework (MOF) to unlock their potential for Li+ storage. TQ was identified redox activity with Li+ for the first time. With a synergistic effect of TQ and CuO4 unit, the 2D conductive MOF, named Cu‐HHTQ (HHTQ=2,3,7,8,12,13‐hexahydroxytricycloquinazoline), can facilitate the Li+/e− transport and ensure a resilient electrode, resulting in a high capacity of 657.6 mAh g−1 at 600 mA g−1 with extraordinary high‐rate capability and impressive cyclability. Our findings highlight an efficient strategy of constructing electrode materials for energy storage with combining multiple redox‐active moieties into conductive MOFs.
The 2D conductive metal–organic framework Cu‐HHTQ with multiple redox‐active sites originating from a nitrogen‐rich aromatic molecule tricycloquinazoline (TQ) and a CuO4 unit was designed for Li‐ion batteries with high capacity, extraordinary high‐rate capability and impressive cyclability. TQ was identified as redox‐active with Li+ for the first time.
Sulfurized polyacrylonitrile is suggested to contain S
(n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether ...electrolytes suggest that high solubility of Li
S
(n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g
at 0.2 A g
), 84% active material utilization and high rate (capacity up to 900 mA h g
at 10 A g
). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li
S
(n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.
Improving the low-temperature activity (below 100 °C) and noble-metal efficiency of automotive exhaust catalysts has been a continuous effort to eliminate cold-start emissions, yet great challenges ...remain. Here we report a strategy to activate the low-temperature performance of Pt catalysts on Cu-modified CeO2 supports based on redox-coupled atomic layer deposition. The interfacial reducibility and structure of composite catalysts have been precisely tuned by oxide doping and accurate control of Pt size. Cu-modified CeO2-supported Pt sub-nanoclusters demonstrate a remarkable performance with an onset of CO oxidation reactivity below room temperature, which is one order of magnitude more active than atomically-dispersed Pt catalysts. The Cu-O-Ce site with activated lattice oxygen anchors deposited Pt sub-nanoclusters, leading to a moderate CO adsorption strength at the interface that facilitates the low-temperature CO oxidation performance.Improving low-temperature activity and noble-metal efficiency remains a challenge for next generation exhaust catalysts. Here, the authors achieve the activation of subnanometric Pt on Cu-modified CeO2 for low-temperature CO oxidation with an onset below room temperature.
The low efficiency and fast degradation of devices from ink-jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states ...caused by both anion and cation under-coordinated sites on the quantum dot surface with proper ligands for ink-jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink-jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink-jet printing processing for possible mass production. And the performance from ink-jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry.
Hollow carbon nanostructures have inspired numerous interests in areas such as energy conversion/storage, biomedicine, catalysis, and adsorption. Unfortunately, their synthesis mainly relies on ...template-based routes, which include tedious operating procedures and showed inadequate capability to build complex architectures. Here, by looking into the inner structure of single polymeric nanospheres, we identified the complicated compositional chemistry underneath their uniform shape, and confirmed that nanoparticles themselves stand for an effective and versatile synthetic platform for functional hollow carbon architectures. Using the formation of 3-aminophenol/formaldehyde resin as an example, we were able to tune its growth kinetics by controlling the molecular/environmental variables, forming resin nanospheres with designated styles of inner constitutional inhomogeneity. We confirmed that this intraparticle difference could be well exploited to create a large variety of hollow carbon architectures with desirable structural characters for their applications; for example, high-capacity anode for potassium-ion battery has been demonstrated with the multishelled hollow carbon nanospheres.
Composite Co3O4/TiO2 nanotube arrays (NTs) were fabricated via atomic layer deposition (ALD) of Co3O4 thin film onto well-aligned anodized TiO2 NTs. The microscopic morphology, composition, and ...interfacial plane of the composite structure were characterized by scanning electron microscopy, energy dispersion mapping, X-ray photoelectron spectra, and high-resolution transmission electron microscopy. It was shown that the ultrathin Co3O4 film uniformly coat onto the inner wall of the high aspect ratio (>100:1) TiO2 NTs with film thickness precisely controlled by the number of ALD deposition cycles. The composite structure with ∼4 nm Co3O4 coating revealed optimal photoelectrochemical (PEC) performance in the visible-light range (λ > 420 nm). The photocurrent density reaches as high as 90.4 μA/cm2, which is ∼14 times that of the pristine TiO2 NTs and 3 times that of the impregnation method. The enhanced PEC performance could be attributed to the finely controlled Co3O4 coating layer that enhances the visible-light absorption, maintains large specific surface area to the electrolyte interface, and facilitates the charge transfer.
The detailed lithospheric structure of South China is the basis for the understanding of tectonic processes of eastern China. Specifically, two essential issues in the study of lithospheric structure ...are the thermal and compositional structures, which are usually derived from either geophysical or geochemical observations. However, inversions from single geophysical or geochemical datasets have certain limitations, making it necessary to develop joint inversions of geophysical, geochemical and petrological datasets. In this paper, through thermodynamic simulation and probabilistic inversion, we inverted multiple datasets including topography, geoid height, surface heat flow and surface wave dispersion curves for the 3D lithospheric thermal and compositional structure of South China. The results reveal a thin (< 100 km) and flat LAB beneath the South China Fold System Block and the lower Yangtze Craton. Also, we found that the lithospheric mantle is primarily composed of saturated peridotite, indicating that the ancient refractory lithospheric mantle has been replaced by new materials. The dominant dynamic mechanism for lithospheric thinning in eastern South China may be the flat subduction of ancient Pacific slab, while thermal erosion may have also played a significant role. In contrast, the LAB depth beneath the Sichuan Basin is much thicker (> 200 km), suggesting that the thick and cold craton lithospheric roots are retained. There may exist a discontinuous interface beneath the Sichuan Basin, with the saturated lower layer thicker than the refractory upper layer. As a result, the lithospheric mantle of the Sichuan Basin and surrounding regions is mainly composed of saturated and transitional peridotite.
Hollow nanoporous carbon architectures (HNCs) present significant utilitarian value for a wide variety of applications. Facile and efficient preparation of HNCs has long been pursued but still ...remains challenging. Herein, we for the first time demonstrate that single‐component metal–organic frameworks (MOFs) crystals, rather than the widely reported hybrid ones which necessitate tedious operations for preparation, could enable the facile and versatile syntheses of functional HNCs. By controlling the growth kinetics, the MOFs crystals (STU‐1) are readily engineered into different shapes with designated styles of crystalline inhomogeneity. A subsequent one‐step pyrolysis of these MOFs with intraparticle difference can induce a simultaneous self‐hollowing and carbonization process, thereby producing various functional HNCs including yolk‐shell polyhedrons, hollow microspheres, mesoporous architectures, and superstructures. Superior to the existing methods, this synthetic strategy relies only on the complex nature of single‐component MOFs crystals without involving tedious operations like coating, etching, or ligand exchange, making it convenient, efficient, and easy to scale up. An ultra‐stable Na‐ion battery anode is demonstrated by the HNCs with extraordinary cyclability (93 % capacity retention over 8000 cycles), highlighting a high level of functionality of the HNCs.
It is for the first time found that single‐component MOFs (STU‐1) crystals with inner crystalline inhomogeneity could enable the facile and versatile syntheses of hollow nanoporous carbon architectures (HNCs) through an unexplored spontaneous hollowing mechanism. The obtain HNCs can act as a high‐capacity and ultra‐stable anode for Na‐ion batteries.
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