Polyoxometalates (POMs) are a series of molecular metal oxide clusters, which span the two domains of solutes and solid metal oxides. The unique characters of POMs in structure, geometry, and ...adjustable redox properties have attracted widespread attention in functional material synthesis, catalysis, electronic devices, and electrochemical energy storage and conversion. This review is focused on the links between the intrinsic charge carrier behaviors of POMs from a chemistry‐oriented view and their recent ground‐breaking developments in related areas. First, the advantageous charge transfer behaviors of POMs in molecular‐level electronic devices are summarized. Solar‐driven, thermal‐driven, and electrochemical‐driven charge carrier behaviors of POMs in energy generation, conversion and storage systems are also discussed. Finally, present challenges and fundamental insights are discussed as to the advanced design of functional systems based upon POM building blocks for their possible emerging application areas.
The links between the intrinsic charge‐carrier behaviors of polyoxometalates (POMs) from a chemistry‐oriented view are discussed and their recent ground‐breaking developments in related areas, including molecular‐level electronic devices, solar‐driven, thermally driven, and electrochemically driven energy generation, conversion, and storage systems are reviewed. Finally, present challenges and the fundamental insights for advanced design and self‐assembly of POM building blocks are also discussed.
An composite comprising amorphous carbon nitride (ACN) and zinc oxide is derived from ZIF‐8 by pyrolysis. The composite is a promising anode material for sodium‐ion batteries. The nitrogen content of ...the ACN composite is as high as 20.4 %, and the bonding state of nitrogen is mostly pyridinic, as determined by X‐ray photoelectron spectroscopy (XPS). The composite exhibits an excellent Na+ storage performance with a reversible capacity of 430 mA h g−1 and 146 mA h g−1 at current densities of 83 mA g−1 and 8.33 A g−1, respectively. A specific capacity of 175 mA h g−1 was maintained after 2000 cycles at 1.67 A g−1, with only 0.016 % capacity degradation per cycle. Moreover, an accelerating rate calorimetry (ARC) test demonstrates the excellent thermal stability of the composite, with a low self heating rate and high onset temperature (210 °C). These results shows its promise as a candidate material for high‐capacity, high‐rate anodes for sodium‐ion batteries.
Yes we ACN: A composite of amorphous carbon nitride (ACN) and zinc oxide is a promising anode material for sodium‐ion batteries. The composite exhibits excellent cycling stability, rate capability, and thermal stability. The performance is a combination of the sodium ion intercalation chemistry afforded by the carbon nitride and the structural stability imparted by the zinc oxide.
As an important edible traditional Chinese medicine, Codonopsis pilosula has good immunomodulation effects. This study focuses on C. pilosula oligosaccharides (CPO), which are the sweetness ...components of C. pilosula. CPO were obtained through systematic separation and purification (the yield is 14.3%), and the effect of CPO on the immunological activities of immunocompromised mice induced by cyclophosphamide (CTX) was evaluated. The results showed that CPO could increase immune organ indices, phagocytic index and immunoglobulin contents, stimulate the proliferation of splenic lymphocytes (coordinating with ConA and LPS), enhance the earlap swelling of the DTH reaction, promote the production of NO and cytokines (IL-2 and IFN-γ) and upregulate the expression of the corresponding mRNA. In addition, CPO upregulated the protein expression of phosphorylated p38, phosphorylated ERK1/2 and phosphorylated JNK, which indicated that CPO might exert immunomodulatory effects through the MAPK signaling pathway. These findings indicated that CPO are important immunomodulatory components in C. pilosula and could be developed as immunomodulators in medicine or functional food areas.
The quasi-solid-state electrolytes (QSSEs) with an inorganic skeleton, a solid–liquid composite material combining their respective merits, exhibit high ionic conductivity and mechanical strength. ...However, most quasi-solid electrolytes prepared by immobilizing ionic liquid (IL) or organic liquid electrolyte in inorganic scaffold generally have poor interface compatibility and low lithium ion migration number, which limits its application. Herein, we design and prepare a ZIF-8-based QSSE (ZIF-8 QSSE) in which the ZIF-8 has a special cage structure and interaction with the guest electrolyte to form a composite electrolyte with good ionic conductivity about 1.05 × 10–4 S cm–1 and a higher lithium-ion transference number of about 0.52. With the ZIF-8 QSSE, a protype lithium battery coupled with LiCoO2 cathode shows good electrochemical performances with an initial discharge capacity of 135 mAh g–1 at 50 mA g–1 and a remaining capacity of 119 mAh g–1 after 100 cycles, only 0.119% capacity degradation per cycle. It is worth noting that the ZIF-8-based QSSEs have good thermal stability up to 350 °C that does not show thermal runaway, which is significantly higher than that of a conventional organic liquid battery system.
An electron conductive matrix, or collector, facilitates electron transport in an electrochemical device. It is stationary and does not change during the entire operation once it is built. The ...interface of this matrix and an electrode is constructed at a 2D level at the micro‐scale, and naturally limits the breadth and depth of electrochemical reactions. Herein, the idea of an enhanced electrode coupled with a conducting molecule that can extend interfacial reactions is first introduced. With a spatialized interspace, this electrode can change the present understanding of the electrode process and opens up a new realm of electrode‐based reaction chemistry. A lithium–sulfur (Li–S) battery is used as the target for implementing the enhanced electrode owing to the complex multi‐electron reaction. Through the interaction of π–π stacking between graphite‐based carbon and iron (II) phthalocyanine (FePc), soluble FePc can be decorated on the surface of an electrode that has the capability of transporting electrons. The scanning tunneling microscope break junction characterization and density functional theory indicate that FePc has a strong molecular electronic conductivity. The reactants obtain electrons more easily from the conducting molecule than from the collector directly. As a result, the performance of the corresponding Li–S battery considerably improves.
An enhanced electrode via decoration of a special electron conductive molecule (FePc) on a conductive matrix surface is reported that allows extended interfacial reactions. The electron transport path from electrode to electrolyte is then stretched into the body phase rather than limited to the interface, thus spatializing the interface into the interspace. This technique is expected to significantly improve the performance of lithium‐sulfur batteries.
Metallic sodium is considered the most likely anode material to replace metallic lithium owing to its high theoretical capacity, abundant reserves, and low cost. However, the uneven deposition and ...agglomerate deposition of Na often result in low coulombic efficiency and inferior lifetime during cycling. Here, by phosphorizing treatment, a sodiophilic phosphorized copper mesh (PCM) has been achieved as the metallic sodium-host current collector for the first time; then through
in situ
electrochemical reaction construct, sodiophilic Na-Cu-P composite layer, which has a fast electronic/ionic conductivity and strong adsorption ability with sodium, thereby greatly mitigating electrodeposition overpotential for improving Na plating/stripping behaviors. Meanwhile, the cross-linked mesh skeleton significantly diminishes the local current density, thus achieving highly reversible Na plating/stripping behavior with dendrite-free and "dead Na"-free. Consequently, the PCM electrode can maintain a high coulombic efficiency (∼99.96%) over 1000 cycles at 5 mA cm
−2
and exhibit an ultra-low electrodeposition overpotential from 0.5 mA cm
−2
to 10 mA cm
−2
in a half-cell. Similarly, the symmetrical cell displays superior cycling stability with low overpotential. Furthermore, the PCM@Na anode delivers excellent cycling/rate performance when paired with Prussian blue (PB) cathode in full-cell.
Herein, we successfully introduce a sodiophilic Na-Cu-P composites
via in situ
alloying reaction, which can greatly mitigate the tip/growth/nucleation overpotential during Na deposition, thereby to realize a stable Na plating/stripping behaviors.
Through a facile impregnation and pyrolysis treatment, a nitrogen-doped carbon nanoflake array rich in uniform and abount Co quantum dots (CoQD) on 3D glass fibers can been successfully prepared, ...which possess the superior lithophilicity and conductivity. Thus, the small nucleation barrier and evenly/rapidly Li deposition could be achieved.
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•GFLA anode is prepared via a two-step method and as the Li-host for the first time.•CoQD@NC nanoflakes can effectively improve the lithiophilicity and conductivity.•GFLA anode performs small nucleation barrier and evenly/rapidly Li deposition.•GFLA anode exhibits superior performance in half/symmetrical/full-cell.
Nonconducting textile materials will be the skeleton of electrode for flexible battery in growing widespread applications in portable and wearable electronics, a fiber-based lithium anode is facing more challenges and has more important sense. Herein, a glass fiber was employed as supporting skeleton on which the nitrogen-doped carbon nanoflake array has been modified first to form a conductive layer, then the cobalt quantum dots were embedded in the layer to establish lithophilic sites, finally, a unique glass-fiber-based lithium anode (GFLA) has been achieved. Furthermore, the cross-linked fiber framework not only dramatically lessen the local current density, but the richer cavity also greatly alleviates the volume expansion problem. Thus, the GFLA electrode demonstrated a highly reversible and stable long-term cycling behavior with nondendritic. As expected, the GFLA electrode exhibits a high CE (∼98.64%) at 0.5 mA cm−2 upon 1480 h in half-cell and a durable cycling with a small voltage hysteresis (20 mV) for 470 h at 4 mA cm−2/4 mAh cm−2 in symmetrical-cell. Moreover, the GFLA@Li||LiFePO4 full-cell displays a capacity retention rate of up to 90.3% after 400 cycles, while the carbon fiber@Li||LiFePO4 is only 36.4%.
The rechargeable lithium-sulfur battery is regarded as a promising option for electrochemical energy storage systems owing to its high energy density, low cost and environmental friendliness. Further ...development of the Li-S battery, however, is still impeded by capacity decay and kinetic sluggishness caused by the polysulfide shuttle and electrode/electrolyte interface issues. Herein, a new type of metal-organic-framework-derived sulfur host containing cobalt and N-doped graphitic carbon (Co-N-GC) was synthesized and reported, in which the catalyzing for S redox, entrapping of polysulfides and an ideal electronic matrix were successfully achieved synchronously, leading to a significant improvement in the Li-S performance. The large surface area and uniform dispersion of cobalt nanoparticles within the N-doped graphitic carbon matrix contributed to a distinct enhancement in the specific capacity, rate performance and cycle stability for Li-S batteries. As a result of this multi-functional arrangement, cathodes with a high sulfur loading of 70 wt% could operate at 1C for over 500 cycles with nearly 100% coulombic efficiency and exhibited an outstanding high-rate response of up to 5C, suggesting that the SatCo-N-GC electrode was markedly improved by the proposed strategy, demonstrating its great potential for use in low-cost and high-energy Li-S batteries.
