Novel composite separators containing metal–organic‐framework (MOF) particles and poly(vinyl alcohol) are fabricated by the electrospinning process. The MOF particles containing opened metal sites ...can spontaneously adsorb anions while allowing effective transport of lithium ions in the electrolyte, leading to dramatically improved lithium‐ion transference number tLi+ (up to 0.79) and lithium‐ion conductivity. Meanwhile, the incorporation of the MOF particles alleviates the decomposition of the electrolyte, enhances the electrode reaction kinetics, and reduces the interface resistance between the electrolyte and the electrodes. Implementation of such composite separators in conventional lithium‐ion batteries leads to significantly improved rate capability and cycling durability, offering a new prospective toward high‐performance lithium‐ion batteries.
An electrospun composite separator comprising metal–organic frameworks with open metal sites (OMSs) is developed for high‐rate lithium‐ion batteries, where the OMSs can efficiently immobilize anions in the electrolyte and afford highly mobile lithium ions. This work opens up new opportunities for functional separators aiming at regulating ion transport in the electrolyte and achieving a high rate capability of batteries.
As a novel class of dynamic and non‐covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible ...changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide‐ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bioimaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplinary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology.
Functional supramolecular polymers not only display unique structures and specific functions, but also have the ability to undergo reversible changes of structure, morphology, and function in response to various external stimuli. In this Review, the representative achievements in the design and synthesis of functional supramolecular polymers are summarized, along with their use in a wide range of applications in the biomedical field.
Electrical energy storage plays an increasingly important role in modern society. Current energy storage methods are highly dependent on lithium-ion energy storage devices, and the expanded use of ...these technologies is likely to affect existing lithium reserves. The abundance of sodium makes Na-ion-based devices very attractive as an alternative, sustainable energy storage system. However, electrodes based on transition-metal oxides often show slow kinetics and poor cycling stability, limiting their use as Na-ion-based energy storage devices. The present paper details a new direction for electrode architectures for Na-ion storage. Using a simple hydrothermal process, we synthesized interpenetrating porous networks consisting of layer-structured V(2)O(5) nanowires and carbon nanotubes (CNTs). This type of architecture provides facile sodium insertion/extraction and fast electron transfer, enabling the fabrication of high-performance Na-ion pseudocapacitors with an organic electrolyte. Hybrid asymmetric capacitors incorporating the V(2)O(5)/CNT nanowire composites as the anode operated at a maximum voltage of 2.8 V and delivered a maximum energy of ∼40 Wh kg(-1), which is comparable to Li-ion-based asymmetric capacitors. The availability of capacitive storage based on Na-ion systems is an attractive, cost-effective alternative to Li-ion systems.
High‐performance asymmetric super‐capacitors containing thick‐film electrodes (over 100 μm thick) made of CNT/V2O5 nanowire composite are designed. The excellent conductivity, high specific ...capacitance, and a large voltage window of the CNT/V2O5 nanocomposite enable the fabrication of devices with high energy and high power densities. Moreover, the resulting devices exhibit excellent cycling stability. This supercapacitor approach may be attractive for a wide range of device applications.
Building nanocomposite architectures based on nanocarbon materials (such as carbon nanotubes and graphene nanosheets) and metal‐oxide nanoparticles is of great interests for electrochemical energy ...storage. Here, an ionic‐liquid‐assisted strategy is presented to mediate the in situ growth of TiO2 nanocrystals with controlled size on carbon nanotubes and graphene, and also reduce the modified carbon supports to recover the graphitic structure simultaneously. The as‐prepared nanocomposites exhibit a highly porous and robust structure with intimate coupling between TiO2 nanocrystals and carbon supports, which offers facile ion and electron transport pathway as well as high mechanical stability. When evaluated as electrode materials for lithium‐ion batteries, the nanocomposites manifest high specific capacity, long cycling lifetime, and excellent rate capability, showing their promising application in high‐performance energy storage devices.
A one‐step ionic‐liquid (IL)‐assisted approach is developed to fabricate TiO2–carbon nanocomposites for battery anodes. The IL mediates the uniform growth of TiO2 nanocrystals with controlled size on nanocarbons with intimate contact and in situ reduces the modified carbon supports to recover the graphitic structure. This leads to nanocomposites with high specific capacity, long cycling lifetime, and excellent rate capability.
Limited by the size of microelectronics, as well as the space of electrical vehicles, there are tremendous demands for lithium-ion batteries with high volumetric energy densities. Current lithium-ion ...batteries, however, adopt graphite-based anodes with low tap density and gravimetric capacity, resulting in poor volumetric performance metric. Here, by encapsulating nanoparticles of metallic tin in mechanically robust graphene tubes, we show tin anodes with high volumetric and gravimetric capacities, high rate performance, and long cycling life. Pairing with a commercial cathode material LiNi
Mn
Co
O
, full cells exhibit a gravimetric and volumetric energy density of 590 W h Kg
and 1,252 W h L
, respectively, the latter of which doubles that of the cell based on graphite anodes. This work provides an effective route towards lithium-ion batteries with high energy density for a broad range of applications.
The application of graphene for electrochemical energy storage has received tremendous attention; however, challenges remain in synthesis and other aspects. Here we report the synthesis of ...high-quality, nitrogen-doped, mesoporous graphene particles through chemical vapor deposition with magnesium-oxide particles as the catalyst and template. Such particles possess excellent structural and electrochemical stability, electronic and ionic conductivity, enabling their use as high-performance anodes with high reversible capacity, outstanding rate performance (e.g., 1,138 mA h g
at 0.2 C or 440 mA h g
at 60 C with a mass loading of 1 mg cm
), and excellent cycling stability (e.g., >99% capacity retention for 500 cycles at 2 C with a mass loading of 1 mg cm
). Interestingly, thick electrodes could be fabricated with high areal capacity and current density (e.g., 6.1 mA h cm
at 0.9 mA cm
), providing an intriguing class of materials for lithium-ion batteries with high energy and power performance.
Abstract
The sluggish electrochemical kinetics of sulfur species has impeded the wide adoption of lithium-sulfur battery, which is one of the most promising candidates for next-generation energy ...storage system. Here, we present the electronic and geometric structures of all possible sulfur species and construct an electronic energy diagram to unveil their reaction pathways in batteries, as well as the molecular origin of their sluggish kinetics. By decoupling the contradictory requirements of accelerating charging and discharging processes, we select two pseudocapacitive oxides as electron-ion source and drain to enable the efficient transport of electron/Li
+
to and from sulfur intermediates respectively. After incorporating dual oxides, the electrochemical kinetics of sulfur cathode is significantly accelerated. This strategy, which couples a fast-electrochemical reaction with a spontaneous chemical reaction to bypass a slow-electrochemical reaction pathway, offers a solution to accelerate an electrochemical reaction, providing new perspectives for the development of high-energy battery systems.
Supercapacitors have high power densities, high efficiencies, and long cycling lifetimes; however, to enable their wider use, their energy densities must be significantly improved. The design and ...synthesis of improved carbon materials with better capacitance, rate performance, and cycling stability has emerged as the main theme of supercapacitor research. Herein, we report a facile synthetic method to prepare nitrogen-rich carbon particles based on a continuous aerosol- spraying process. The method yields particles that have high surface areas, a uniform microporous structure, and are highly N-doped, resulting in a synergism that enables the construction of supercapacitors with high energy and power density for use in both aqueous and commercial organic electrolytes. Furthermore, we have used density functional theory calculations to show that the improved performance is due to the enhanced wettability and ion adsorption interactions at the carbon/electrolyte interface that result from nitrogen doping. These findings provide new insights into the role of heteroatom doping in the capacitance enhancement of carbon materials; in addition, our method offers an efficient route for large-scale production of doped carbon.
Life relies on numerous biochemical processes working synergistically and correctly. Certain substances disrupt these processes, inducing living organism into an abnormal state termed intoxication. ...Managing intoxication usually requires interventions, which is referred as detoxification. Decades of development on detoxification reveals the potential of enzymes as ideal therapeutics and antidotes, because their high substrate specificity and catalytic efficiency are essential for clearing intoxicating substances without adverse effects. However, intrinsic shortcomings of enzymes including low stability and high immunogenicity are major hurdles, which could be overcome by delivering enzymes with specially designed nanocarriers. Extensive investigations on protein delivery indicate three types of enzyme-nanocarrier architectures that show more promise than others for systemic detoxification, including liposome-wrapped enzymes, polymer–enzyme conjugates, and polymer-encapsulated enzymes. This review highlights recent advances in these nano-architectures and discusses their applications in systemic detoxifications. Therapeutic potential of various enzymes as well as associated challenges in achieving effective delivery of therapeutic enzymes will also be discussed.
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